Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's book .
.. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE, or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the instructions on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL strength -
that depends on the repair you did on the core. When 'mat' is mentioned, it
indicates that there is some substantial thickness involved. Also, the last
layer should be cloth. {followed by a couple of coats of Gelcoat or some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

On my first boat (a stitch and glue dinghy), I carefully read both the
Gougeon Brothers and System Three's directions and put the small tape down
first with the larger on top. I did not put on sufficient fairing compound,
so when I sanded, the wider tape was quickly cut down by the ridge at the
selvedge edge of the narrower layer. Since then I've been putting the
narrow tape on top. I really don't think it matters much.

Roger

http://home.insightbb.com/~derbyrm

"Ron Magen" wrote in message
news:t0Fmg.515$uo.477@trnddc07...
Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's book
.
. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE, or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the instructions
on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL strength -
that depends on the repair you did on the core. When 'mat' is mentioned,
it
indicates that there is some substantial thickness involved. Also, the
last
layer should be cloth. {followed by a couple of coats of Gelcoat or some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Yes, I have read both West System books and Don Casey's book very
carefully. That's why I discover the difference between their two
approaches. Otherwise, I might not even notice the difference.

I don't know which West System literature that you are referring to
because I cannot find the examples that you have mentioned in the West
System books that I have. The one that I read the most often is called
"Fiberglass Boat Repair & Maintenance" (around 86 pages) (June 2004
Edition). They use the "largest one first / smallest one last"
approach consistantly through out the whole literature. Examples:
- To stiffen the floor and stringers (p. 17 18, and 20)
- To repair hull from the outside (p. 25 and 27)
- To re-attach outer skin to the deck from above (p. 33)
- To re-attach outer skin to the transom from outside (p. 37)
- To lay up a new outer skin to the transom from outside (p. 38)

That's just the opposition to the approach that I see in Don Casey's
book.

I figure that either approach is probably fine.

Jay Chan

Ron Magen wrote:
Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's book .
. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE, or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the instructions on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL strength -
that depends on the repair you did on the core. When 'mat' is mentioned, it
indicates that there is some substantial thickness involved. Also, the last
layer should be cloth. {followed by a couple of coats of Gelcoat or some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

You mean your copy of West System book also says to put the largest
piece last. This is odd because this is the opposite of what I read in
the June-2004 edition of West System literature called "Fiberglass Boat
Repair & Maintenance". I have a feeling that they might have changed
their approach within the last couple years -- not sure.

As what your experience showed, we may encounter a small problem if we
put the largest piece last. We can sand away some of the largest piece
of fiberglass cloth if we don't put enough fairing compound to protect
the fiberglass cloth, and may reduce the strength of the largest
fiberglass cloth. On the other hand, if we put the smallest piece
last, we will only sand away the edge of the fiberglass cloth. I guess
that may be the reason why West System suggest putting the smallest
piece last. I guess I will stick with the approach that West System
has suggested.

Anyway, as what you have said, this probably doesn't matter much.
Either approach will be fine if we put enough fairing compound to
protect the fiberglass cloth.

Thanks for sharing your experience.

Jay Chan

derbyrm wrote:
On my first boat (a stitch and glue dinghy), I carefully read both the
Gougeon Brothers and System Three's directions and put the small tape down
first with the larger on top. I did not put on sufficient fairing compound,
so when I sanded, the wider tape was quickly cut down by the ridge at the
selvedge edge of the narrower layer. Since then I've been putting the
narrow tape on top. I really don't think it matters much.

Roger

http://home.insightbb.com/~derbyrm

"Ron Magen" wrote in message
news:t0Fmg.515$uo.477@trnddc07...
Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's book
.
. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE, or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the instructions
on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL strength -
that depends on the repair you did on the core. When 'mat' is mentioned,
it
indicates that there is some substantial thickness involved. Also, the
last
layer should be cloth. {followed by a couple of coats of Gelcoat or some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

If you go from the smallest piece first you have a chance of trapping
concentric rings or squares of bubbles in the laminate. Sam

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

It's been some time since I read it, and I was paying attention to the
joining of plywood sheets along the edges, not patching a fiberglass hull.
What I read was "Gougeon Brothers on Boat Construction," and I watched their
video a couple of times.

That said, I still don't think it makes any structural difference.
Cosmetic? Yes, probably.

Roger

http://home.insightbb.com/~derbyrm

wrote in message
oups.com...
You mean your copy of West System book also says to put the largest
piece last. This is odd because this is the opposite of what I read in
the June-2004 edition of West System literature called "Fiberglass Boat
Repair & Maintenance". I have a feeling that they might have changed
their approach within the last couple years -- not sure.

As what your experience showed, we may encounter a small problem if we
put the largest piece last. We can sand away some of the largest piece
of fiberglass cloth if we don't put enough fairing compound to protect
the fiberglass cloth, and may reduce the strength of the largest
fiberglass cloth. On the other hand, if we put the smallest piece
last, we will only sand away the edge of the fiberglass cloth. I guess
that may be the reason why West System suggest putting the smallest
piece last. I guess I will stick with the approach that West System
has suggested.

Anyway, as what you have said, this probably doesn't matter much.
Either approach will be fine if we put enough fairing compound to
protect the fiberglass cloth.

Thanks for sharing your experience.

Jay Chan

derbyrm wrote:
On my first boat (a stitch and glue dinghy), I carefully read both the
Gougeon Brothers and System Three's directions and put the small tape
down
first with the larger on top. I did not put on sufficient fairing
compound,
so when I sanded, the wider tape was quickly cut down by the ridge at the
selvedge edge of the narrower layer. Since then I've been putting the
narrow tape on top. I really don't think it matters much.

Roger

http://home.insightbb.com/~derbyrm

"Ron Magen" wrote in message
news:t0Fmg.515$uo.477@trnddc07...
Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's
book
.
. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE,
or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the
instructions
on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers
of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the
strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL
strength -
that depends on the repair you did on the core. When 'mat' is
mentioned,
it
indicates that there is some substantial thickness involved. Also, the
last
layer should be cloth. {followed by a couple of coats of Gelcoat or
some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered
edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

There's a simple fix for the smallest-piece-first method and the use of
fairing compound ...stop letting the tape cure in between applications of
tape. In other words, if you put the tape on wet-on-wet, then you don't
need to scrape, sand, fill with fairing compound, etcetera in between layers
just so you can properly taper the edges on the previous layer. The
"Gougeon Brothers on Boat Construction" book describes this technique, and
also recommends pre-wetting the fiberglass tape prior to installation. I
find that in the majority of installations, that pre-wetting and
installation of glass wet-on-wet can be done, and only once in awhile is
there reason to take a different approach. Here's my pre-wetting box:

http://www.glacierboats.com/tongass/...3-1336_img.jpg

I've built seams with as many as 3 layers of glass with the wet-on-wet
pre-wetting method. I lay down the widest tape in the box seen above, wet
it out with just barely enough epoxy to wet it out properly, then lay down
the medium width tape on top of it and wet it out, then the narrowest tape
on top of that and wet it out. If you keep trying to use 'barely enough'
epoxy and let it absorb into the glass tape at it's own rate (don't rush
it), then you'll get an optimal layup right in the pre-wetting box. Roll it
up, carry it to the boat, and unroll it along the seem and massage/stroke it
into place with gloved hands, narrowest-width tape against the fillet. The
outer layers of glass naturally press the inner layers smooths and liquid
epoxy will naturally fill the edge transition areas and what not. Done.
Scrape/sand/fair the outer tape when the whole stack has cured.

Brian D


wrote in message
oups.com...
You mean your copy of West System book also says to put the largest
piece last. This is odd because this is the opposite of what I read in
the June-2004 edition of West System literature called "Fiberglass Boat
Repair & Maintenance". I have a feeling that they might have changed
their approach within the last couple years -- not sure.

As what your experience showed, we may encounter a small problem if we
put the largest piece last. We can sand away some of the largest piece
of fiberglass cloth if we don't put enough fairing compound to protect
the fiberglass cloth, and may reduce the strength of the largest
fiberglass cloth. On the other hand, if we put the smallest piece
last, we will only sand away the edge of the fiberglass cloth. I guess
that may be the reason why West System suggest putting the smallest
piece last. I guess I will stick with the approach that West System
has suggested.

Anyway, as what you have said, this probably doesn't matter much.
Either approach will be fine if we put enough fairing compound to
protect the fiberglass cloth.

Thanks for sharing your experience.

Jay Chan

derbyrm wrote:
On my first boat (a stitch and glue dinghy), I carefully read both the
Gougeon Brothers and System Three's directions and put the small tape
down
first with the larger on top. I did not put on sufficient fairing
compound,
so when I sanded, the wider tape was quickly cut down by the ridge at the
selvedge edge of the narrower layer. Since then I've been putting the
narrow tape on top. I really don't think it matters much.

Roger

http://home.insightbb.com/~derbyrm

"Ron Magen" wrote in message
news:t0Fmg.515$uo.477@trnddc07...
Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's
book
.
. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE,
or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the
instructions
on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers
of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the
strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL
strength -
that depends on the repair you did on the core. When 'mat' is
mentioned,
it
indicates that there is some substantial thickness involved. Also, the
last
layer should be cloth. {followed by a couple of coats of Gelcoat or
some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered
edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

On 2006-06-24 03:26:42 -0400, ray lunder said:

And don't forget to put a sheet of plastic between the core and resin
if you're working next to the core. (the foam reacts with the epoxy
and gasses, leaving voids).

This is rather bad advice. In almost all cases, you WANT THE RESIN AND
PATCH TO BOND TO THE CORE. Putting plastic between the core and the
resin leaves a void too, just not one filled with gasses. Most cores
DO NOT react to Epoxy by dissolving and gassing off... especially if
the core is a good end-grain balsa, which it is on the better boats. If
the core is not bonded to the repaired area, you have effectively
created a section that is pre-delaminated. DUH.

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

On the OP's question, smallest piece first will be stronger
(assuming a good bond). Depends on what you want. You can
also put down more than 3 layers wet-on-wet, I've done five
or six at a time (using slow set resin) and it works just
fine. The prep work is the key.


And don't forget to put a sheet of plastic between the core and resin
if you're working next to the core. (the foam reacts with the epoxy
and gasses, leaving voids).


???

Isn't the point to bond the core to the surface? If you're
getting that much reaction & gas, you're doing something wrong.


dog wrote:
This is rather bad advice. In almost all cases, you WANT THE RESIN AND
PATCH TO BOND TO THE CORE. Putting plastic between the core and the
resin leaves a void too, just not one filled with gasses. Most cores DO
NOT react to Epoxy by dissolving and gassing off... especially if the
core is a good end-grain balsa, which it is on the better boats.

Not tostart an argument, but there are many foams to choose
from and some are lighter & stronger than balsa.

... If the
core is not bonded to the repaired area, you have effectively created a
section that is pre-delaminated.

Yeah, that was kind of what I thought too. But you have to
keep in mind, everybody wants something different.

DSK

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Jay,
I was referring to the Don Casey {hardcover} book. I have no problems with
Gougeon Brothers literature, I just consider them more 'pamphlets'. {They
call them 'manuals'}This is more due to their brevity and physical size
{note the 'punching' so they can be 'filed' in a loose-leaf notebook}.

They do a LOT of work & research. In certain ways they are the pioneers in
the field. However, if you read more of their stuff you will note a lot of
redundancy in the illustrations & text. This is because a lot of 'problems'
have the same 'solution'.

Looking at my comp of 'F'glass Boat Repair . . .' I looks like your looking
at Section 4.2.1 which refers back to Section 3.3. They are talking about
the fiberglass SKIN . . . this is only about 1/8 in thick, at maximum.
{Casey implies about 1in or more} Therefore, if you bevel the edges as shown
there would only be about 1/2 inch, or so, difference between largest &
smallest piece. Follow that with the rest of the outlined technique -
peel-ply, vacuum bagging, {or heavily rolling each layer}, implied
'wet-on-wet' application, etc. - and it really doesn't matter which is put
down first.

What ever you do, allow space for a 'smooth coat' of fairing material, and a
1/32in thick coat of Gelcoat, or paint topcoat to blend in with the rest of
the deck.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
Yes, I have read both West System books and Don Casey's book very
carefully. That's why I discover the difference between their two
approaches. Otherwise, I might not even notice the difference.
SNIP

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Yes, the wet-on-wet method is good and is the method that I intend to
use. But this doesn't seem to have anything to do with
smallest-piece-first, or largest-piece-first. Sound like we should use
wet-on-wet method regardless if we choose smallest-piece-first, or
largest-piece-first. Here, I assume that you are saying this: "Small
piece first or large piece first is not important; the fiberglass tape
will stick well as long as we use wet-on-wet method." Is my
understanding correct?

Thanks for sharing your experience in pre-wetting the fiberglass tapes
before laying them down on the surface. But I guess I will pass on
this one. I don't trust myself not to drip all over the place while I
carry the pre-wetted piece to the boat. Hopefully, other newsgroup
members will find a use of your method. I will stick with laying the
fiberglass cloth dry, blue-taping the fiberglass cloth in place, and
brushing the epoxy on the dry fiberglass cloth.

Thanks.

Jay Chan

Brian D wrote:
There's a simple fix for the smallest-piece-first method and the use of
fairing compound ...stop letting the tape cure in between applications of
tape. In other words, if you put the tape on wet-on-wet, then you don't
need to scrape, sand, fill with fairing compound, etcetera in between layers
just so you can properly taper the edges on the previous layer. The
"Gougeon Brothers on Boat Construction" book describes this technique, and
also recommends pre-wetting the fiberglass tape prior to installation. I
find that in the majority of installations, that pre-wetting and
installation of glass wet-on-wet can be done, and only once in awhile is
there reason to take a different approach. Here's my pre-wetting box:

http://www.glacierboats.com/tongass/...3-1336_img.jpg

I've built seams with as many as 3 layers of glass with the wet-on-wet
pre-wetting method. I lay down the widest tape in the box seen above, wet
it out with just barely enough epoxy to wet it out properly, then lay down
the medium width tape on top of it and wet it out, then the narrowest tape
on top of that and wet it out. If you keep trying to use 'barely enough'
epoxy and let it absorb into the glass tape at it's own rate (don't rush
it), then you'll get an optimal layup right in the pre-wetting box. Roll it
up, carry it to the boat, and unroll it along the seem and massage/stroke it
into place with gloved hands, narrowest-width tape against the fillet. The
outer layers of glass naturally press the inner layers smooths and liquid
epoxy will naturally fill the edge transition areas and what not. Done.
Scrape/sand/fair the outer tape when the whole stack has cured.

Brian D


wrote in message
oups.com...
You mean your copy of West System book also says to put the largest
piece last. This is odd because this is the opposite of what I read in
the June-2004 edition of West System literature called "Fiberglass Boat
Repair & Maintenance". I have a feeling that they might have changed
their approach within the last couple years -- not sure.

As what your experience showed, we may encounter a small problem if we
put the largest piece last. We can sand away some of the largest piece
of fiberglass cloth if we don't put enough fairing compound to protect
the fiberglass cloth, and may reduce the strength of the largest
fiberglass cloth. On the other hand, if we put the smallest piece
last, we will only sand away the edge of the fiberglass cloth. I guess
that may be the reason why West System suggest putting the smallest
piece last. I guess I will stick with the approach that West System
has suggested.

Anyway, as what you have said, this probably doesn't matter much.
Either approach will be fine if we put enough fairing compound to
protect the fiberglass cloth.

Thanks for sharing your experience.

Jay Chan

derbyrm wrote:
On my first boat (a stitch and glue dinghy), I carefully read both the
Gougeon Brothers and System Three's directions and put the small tape
down
first with the larger on top. I did not put on sufficient fairing
compound,
so when I sanded, the wider tape was quickly cut down by the ridge at the
selvedge edge of the narrower layer. Since then I've been putting the
narrow tape on top. I really don't think it matters much.

Roger

http://home.insightbb.com/~derbyrm

"Ron Magen" wrote in message
news:t0Fmg.515$uo.477@trnddc07...
Jay,
I would re-read BOTH the Gudgeon Brothers literature and Don Casey's
book
.
. . carefully.

There are subtle differences between repairing a hole from the OUTSIDE,
or
from the INSIDE. It also depends on whether you are 'laying up' or
'repairing'. It sounds to me that you are looking at the the
instructions
on
pgs. 63 - 67, and the illustrations on pg. 65.

If you will note, the bottom sketch shows the ' . . .alternating layers
of
MAT and CLOTH.}. This is an exaggerated detail of the bevel that is all
around the repair It is a type of 'scarf joint' to give you the
strongest
connection between the 'skin' over the repaired / replaced core and the
remainder of the decking. If you are talking about STRUCTURAL
strength -
that depends on the repair you did on the core. When 'mat' is
mentioned,
it
indicates that there is some substantial thickness involved. Also, the
last
layer should be cloth. {followed by a couple of coats of Gelcoat or
some
other topcoating}

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
I would like to know the right way to lay down layers of fiberglass
clothes over a tapered edge of a fiberglass skin of a deck. Should I
lay down the largest piece first or the smallest piece of fiberglass
cloth first?

The balsa of the cored deck was rotten, and I needed to cut out the
outer skin of the deck (the outer skin was destroyed during the
process), removed the rotten core with good one. When I finally put
good core back in place, I will need to use epoxy and layers of
fiberglass cloths to replace the outerskin of the deck. I am supposed
to grind the edge of the sounding fiberglass skin into a tapered edge,
and then attach the edge of the fiberglass cloths over the tapered
edge
of the surrounding fiberglass skin.

The question is: Should I put the largest piece of fiberglass cloth
first and the smallest piece last like what West System has suggested?
Or should I put the smallest piece first and the largest piece last
like what Don Casey (author of "This Old Boat") has suggested?

I don't care which way "looks" best; all I care is which way can give
me the strongest deck.

Which way is the right way to me?

Thanks in advance for any info.

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

But dripping all over the place is part of the process???? Just try to move
all the expensive tools (planers, belt sanders, etc.) out of the line of
fire.

Roger

http://home.insightbb.com/~derbyrm
wrote in message
oups.com...

snip
I don't trust myself not to drip all over the place while I
carry the pre-wetted piece to the boat.

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

If you are dripping all over the place, then you aren't doing it right. The
glass is supposed to have the weave wetted out, but the weave should still
be quite visible... not dry looking, but dang close. You can apply fill
coats later, after it's cured into the boat. Believe me, the glass has
plenty of epoxy in it when it looks like this. No drips!

Brian


"derbyrm" wrote in message
m...
But dripping all over the place is part of the process???? Just try to
move all the expensive tools (planers, belt sanders, etc.) out of the line
of fire.

Roger

http://home.insightbb.com/~derbyrm
wrote in message
oups.com...

snip
I don't trust myself not to drip all over the place while I
carry the pre-wetted piece to the boat.

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

The following is a RESEND (apparently the picture attachment didn't work
....anybody that wants to see the illustration can email me for it at
briandixon7 AT comcast DOT net)::
-------------------
Wet-on-wet, smallest piece first, results in underlying edges being 'pressed
down' or naturally tapered while wet, and the space near the edges will
naturally fill with liquid epoxy. Since a picture is worth a thousand
words, see the attached image which shows the areas that must be filled in
order to prevent bubbles and to ensure good load transfer from panel to
panel (marked in red.) Wet-on-wet, smallest piece first, takes care of
these areas automatically. If you go largest piece first, you still have to
fair-in (that means scrape, sand, fill, sand.) along the edges ...or should
anyway. I doubt the boat will break either way (grinz.)

Brian D

"Brian D" wrote in message
. ..

If you are dripping all over the place, then you aren't doing it right.
The glass is supposed to have the weave wetted out, but the weave should
still be quite visible... not dry looking, but dang close. You can apply
fill coats later, after it's cured into the boat. Believe me, the glass
has plenty of epoxy in it when it looks like this. No drips!

Brian


"derbyrm" wrote in message
m...
But dripping all over the place is part of the process???? Just try to
move all the expensive tools (planers, belt sanders, etc.) out of the
line of fire.

Roger

http://home.insightbb.com/~derbyrm
wrote in message
oups.com...

snip
I don't trust myself not to drip all over the place while I
carry the pre-wetted piece to the boat.

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Actually, I'm not even using the "off-boat wetted out glass" scheme at the
moment.

All I know is that the epoxy drips end up on many things (like clothing)
that weren't supposed to be wetted. Many come from the epoxy cup where I've
wiped the brush and the stuff has climbed over the edge, run down the side,
and ... Then there's the issue of where to park the swizzle stick and/or
squeegee between uses.

Roger

http://home.insightbb.com/~derbyrm

"Brian D" wrote in message
. ..

If you are dripping all over the place, then you aren't doing it right.
The glass is supposed to have the weave wetted out, but the weave should
still be quite visible... not dry looking, but dang close. You can apply
fill coats later, after it's cured into the boat. Believe me, the glass
has plenty of epoxy in it when it looks like this. No drips!

Brian


"derbyrm" wrote in message
m...
But dripping all over the place is part of the process???? Just try to
move all the expensive tools (planers, belt sanders, etc.) out of the
line of fire.

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

I don't think that I've ever gotten a drip of epoxy falling off a pre-wetted
chunk of fiberglass tape. Of course, by the time I started using that
method, I'd gained enough glassing experience to know how much resin to put
into it, but really ...the glass holds the epoxy quite well. Try it
sometime 'cuz I think you'll like it.

And isn't the concern over a drip here and there a bit like being concerned
about getting wet when you go fishing? Be careful, but don't sweat the
occasional drips and runs. Buy a 3" wide carbide scraper (with handle, and
a knob above the business end) and the SurForm tool with the short handle
and 2" by 1-1/2" (approx) curved cheese-grater on the end and you'll no
longer sweat the little accidents ...they come off easily after curing and
it's easy to leave a smooooth finish behind. Home Despot has these things
for cheap and no epoxy user should be without them. Forget sandpaper for
fixing drips and runs ...bad idea. Relax and enjoy the build.

Enjoy!

Brian D



"derbyrm" wrote in message
m...
Actually, I'm not even using the "off-boat wetted out glass" scheme at the
moment.

All I know is that the epoxy drips end up on many things (like clothing)
that weren't supposed to be wetted. Many come from the epoxy cup where
I've wiped the brush and the stuff has climbed over the edge, run down the
side, and ... Then there's the issue of where to park the swizzle stick
and/or squeegee between uses.

Roger

http://home.insightbb.com/~derbyrm

"Brian D" wrote in message
. ..

If you are dripping all over the place, then you aren't doing it right.
The glass is supposed to have the weave wetted out, but the weave should
still be quite visible... not dry looking, but dang close. You can apply
fill coats later, after it's cured into the boat. Believe me, the glass
has plenty of epoxy in it when it looks like this. No drips!

Brian


"derbyrm" wrote in message
m...
But dripping all over the place is part of the process???? Just try to
move all the expensive tools (planers, belt sanders, etc.) out of the
line of fire.

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

Brian D wrote:
I don't think that I've ever gotten a drip of epoxy falling off a pre-wetted
chunk of fiberglass tape. Of course, by the time I started using that
method, I'd gained enough glassing experience to know how much resin to put
into it, but really ...the glass holds the epoxy quite well. Try it
sometime 'cuz I think you'll like it.


Another good way to pre-wet-out pieces of cloth is to use
PVC sheet. It's commonly sold in varying thickness as
painter's dropcloth. The .5 mil stuff is kinda flimsy but
can be molded around 3-D shapes pretty well, the 3 mil stuff
is pretty strong and I use it for wetting out pre-cut pieces
on a flat bench or floor. It can be re-used almost
infinitely too. Cured epoxy will not stick to it, makes a
great barrier film.

My method is to get a piece of the plastic sheeting that's
at least twice as big as the fiberglass cloth I'm
laminating, lay the cloth into one half of it, then add some
mixed resin. Fold the other half of the sheet over, then
roller it so that the resin gets spread eavenly thru the
cloth and you don't get ick all over your hands or the
roller. You can really get a great resin-glass ratio and
handle the piece without fear of runs or drips.


And isn't the concern over a drip here and there a bit like being concerned
about getting wet when you go fishing? Be careful, but don't sweat the
occasional drips and runs. Buy a 3" wide carbide scraper (with handle, and
a knob above the business end) and the SurForm tool with the short handle
and 2" by 1-1/2" (approx) curved cheese-grater on the end and you'll no
longer sweat the little accidents ...they come off easily after curing and
it's easy to leave a smooooth finish behind. Home Despot has these things
for cheap and no epoxy user should be without them. Forget sandpaper for
fixing drips and runs ...bad idea. Relax and enjoy the build.


Or get a plastic putty knife and scrape up the dripping /
running resin, take it over to your wet-out work area, and
re-use it on the next piece of cloth. Economical and saves
clean-up time.

I've seen a heck of a lot of people working in fiberglass
who seem to bring an unshakeable woodworker's mentality to
the process.... make it thick, then cut it or sand it...
then add some more and sand it off... etc etc. Shucks, the
beauty of molding composites is that you can make it any
shape you want, in less time, and make it *strong*. Get the
material to work for you, not against you.

Not that I'm an expert or anything, but I've made a lot of
stuff out of epoxy resin added to various other materials...
including carbon fiber... over the years.

Fresh Breezes- Doug King

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Some guy posted an article at http://www.duckworksmagazine.com about using
slightly-heavy clear plastic sheeting to fair a boat. If I recall, he put
the glass on the boat, then rolled the sheeting onto it, let it cure and
pulled the sheeting off. The pictures that I saw were marvelous ...glossy
smooth with no imperfections, no boundary marks or lines near edges of
overlapped cloth or at scarfs or anything. Never did give it a try myself
though, but it looked like it worked for him.

I did recently cut off the curved top of a transom to make it flat so I
could run a tuna handline behind the boat (tied to a handline cleat) without
the line rubbing on the transom. It's impossible to get a perfectly
straight cut and all I did to tune it up was to put a thin layer of
microballoon mix + epoxy on it, lay plastic wrap over it, then used a piece
of aluminum angle stock to press the top flat. Came out beautiful. Ready
to fair it in and paint....

Brian D



"DSK" wrote in message
...
Brian D wrote:
I don't think that I've ever gotten a drip of epoxy falling off a
pre-wetted chunk of fiberglass tape. Of course, by the time I started
using that method, I'd gained enough glassing experience to know how much
resin to put into it, but really ...the glass holds the epoxy quite well.
Try it sometime 'cuz I think you'll like it.


Another good way to pre-wet-out pieces of cloth is to use PVC sheet. It's
commonly sold in varying thickness as painter's dropcloth. The .5 mil
stuff is kinda flimsy but can be molded around 3-D shapes pretty well, the
3 mil stuff is pretty strong and I use it for wetting out pre-cut pieces
on a flat bench or floor. It can be re-used almost infinitely too. Cured
epoxy will not stick to it, makes a great barrier film.

My method is to get a piece of the plastic sheeting that's at least twice
as big as the fiberglass cloth I'm laminating, lay the cloth into one half
of it, then add some mixed resin. Fold the other half of the sheet over,
then roller it so that the resin gets spread eavenly thru the cloth and
you don't get ick all over your hands or the roller. You can really get a
great resin-glass ratio and handle the piece without fear of runs or
drips.


And isn't the concern over a drip here and there a bit like being
concerned about getting wet when you go fishing? Be careful, but don't
sweat the occasional drips and runs. Buy a 3" wide carbide scraper (with
handle, and a knob above the business end) and the SurForm tool with the
short handle and 2" by 1-1/2" (approx) curved cheese-grater on the end
and you'll no longer sweat the little accidents ...they come off easily
after curing and it's easy to leave a smooooth finish behind. Home
Despot has these things for cheap and no epoxy user should be without
them. Forget sandpaper for fixing drips and runs ...bad idea. Relax and
enjoy the build.


Or get a plastic putty knife and scrape up the dripping / running resin,
take it over to your wet-out work area, and re-use it on the next piece of
cloth. Economical and saves clean-up time.

I've seen a heck of a lot of people working in fiberglass who seem to
bring an unshakeable woodworker's mentality to the process.... make it
thick, then cut it or sand it... then add some more and sand it off... etc
etc. Shucks, the beauty of molding composites is that you can make it any
shape you want, in less time, and make it *strong*. Get the material to
work for you, not against you.

Not that I'm an expert or anything, but I've made a lot of stuff out of
epoxy resin added to various other materials... including carbon fiber...
over the years.

Fresh Breezes- Doug King

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Thanks for the advice especially about leaving enough space for a layer
of fairing compounding.

Jay Chan

Ron Magen wrote:
Jay,
I was referring to the Don Casey {hardcover} book. I have no problems with
Gougeon Brothers literature, I just consider them more 'pamphlets'. {They
call them 'manuals'}This is more due to their brevity and physical size
{note the 'punching' so they can be 'filed' in a loose-leaf notebook}.

They do a LOT of work & research. In certain ways they are the pioneers in
the field. However, if you read more of their stuff you will note a lot of
redundancy in the illustrations & text. This is because a lot of 'problems'
have the same 'solution'.

Looking at my comp of 'F'glass Boat Repair . . .' I looks like your looking
at Section 4.2.1 which refers back to Section 3.3. They are talking about
the fiberglass SKIN . . . this is only about 1/8 in thick, at maximum.
{Casey implies about 1in or more} Therefore, if you bevel the edges as shown
there would only be about 1/2 inch, or so, difference between largest &
smallest piece. Follow that with the rest of the outlined technique -
peel-ply, vacuum bagging, {or heavily rolling each layer}, implied
'wet-on-wet' application, etc. - and it really doesn't matter which is put
down first.

What ever you do, allow space for a 'smooth coat' of fairing material, and a
1/32in thick coat of Gelcoat, or paint topcoat to blend in with the rest of
the deck.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote in message
ups.com...
Yes, I have read both West System books and Don Casey's book very
carefully. That's why I discover the difference between their two
approaches. Otherwise, I might not even notice the difference.
SNIP

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

I've tried it and it does some nice things, but I've also found several ways
to screw up.

It is mandatory that all air bubbles be gotten out before the epoxy sets up.

If the plastic is folded by the salesperson, it will remember and you'll
have creases (long narrow bubbles). Mutter and fuss until they find a
cardboard tube to roll it on and carry it carefully so it doesn't fold.
(Easier said than done.) Store the plastic carefully.

If there's any outgassing from the wood, it will create a bubble. Best to
first seal the wood with a thin coat of epoxy and sand out the bubbles, but
sometimes the outgassing pinhole acts as if you've tapped a geyser. Hot to
cold works best.

Then there's the frustration of trying to chase each bubble that you notice
to the edge of the plastic.

The epoxy seems to like the sheet plastic better than the fiberglass. If
you miss a bubble, you'll have a crater with the fiberglass at the bottom.
(Small bubbles don't seem to pull the fiberglass away from the wood.) If
you don't get back to it within the three day window for chemical bonding,
then you have to sand the inside of the crater (or drill it out) so the
patch will adhere.

I like it best for fillets. Cut the plastic sheet shorter than the length
of the corner. Roll the fillet with something spherical, or maybe the end
of your roller. You can chase the bubbles the short distance up the side of
the fillet easily. The result is a well faired join.

Between folding and cutting down to size I only get a limited number of
reuses for the plastic.

Roger

http://home.insightbb.com/~derbyrm

"Brian D" wrote in message
. ..

Some guy posted an article at http://www.duckworksmagazine.com about using
slightly-heavy clear plastic sheeting to fair a boat. If I recall, he put
the glass on the boat, then rolled the sheeting onto it, let it cure and
pulled the sheeting off. The pictures that I saw were marvelous ...glossy
smooth with no imperfections, no boundary marks or lines near edges of
overlapped cloth or at scarfs or anything. Never did give it a try myself
though, but it looked like it worked for him.

I did recently cut off the curved top of a transom to make it flat so I
could run a tuna handline behind the boat (tied to a handline cleat)
without the line rubbing on the transom. It's impossible to get a
perfectly straight cut and all I did to tune it up was to put a thin layer
of microballoon mix + epoxy on it, lay plastic wrap over it, then used a
piece of aluminum angle stock to press the top flat. Came out beautiful.
Ready to fair it in and paint....

Brian D



"DSK" wrote in message
...
Brian D wrote:
I don't think that I've ever gotten a drip of epoxy falling off a
pre-wetted chunk of fiberglass tape. Of course, by the time I started
using that method, I'd gained enough glassing experience to know how
much resin to put into it, but really ...the glass holds the epoxy quite
well. Try it sometime 'cuz I think you'll like it.


Another good way to pre-wet-out pieces of cloth is to use PVC sheet. It's
commonly sold in varying thickness as painter's dropcloth. The .5 mil
stuff is kinda flimsy but can be molded around 3-D shapes pretty well,
the 3 mil stuff is pretty strong and I use it for wetting out pre-cut
pieces on a flat bench or floor. It can be re-used almost infinitely too.
Cured epoxy will not stick to it, makes a great barrier film.

My method is to get a piece of the plastic sheeting that's at least twice
as big as the fiberglass cloth I'm laminating, lay the cloth into one
half of it, then add some mixed resin. Fold the other half of the sheet
over, then roller it so that the resin gets spread eavenly thru the cloth
and you don't get ick all over your hands or the roller. You can really
get a great resin-glass ratio and handle the piece without fear of runs
or drips.


And isn't the concern over a drip here and there a bit like being
concerned about getting wet when you go fishing? Be careful, but don't
sweat the occasional drips and runs. Buy a 3" wide carbide scraper
(with handle, and a knob above the business end) and the SurForm tool
with the short handle and 2" by 1-1/2" (approx) curved cheese-grater on
the end and you'll no longer sweat the little accidents ...they come off
easily after curing and it's easy to leave a smooooth finish behind.
Home Despot has these things for cheap and no epoxy user should be
without them. Forget sandpaper for fixing drips and runs ...bad idea.
Relax and enjoy the build.


Or get a plastic putty knife and scrape up the dripping / running resin,
take it over to your wet-out work area, and re-use it on the next piece
of cloth. Economical and saves clean-up time.

I've seen a heck of a lot of people working in fiberglass who seem to
bring an unshakeable woodworker's mentality to the process.... make it
thick, then cut it or sand it... then add some more and sand it off...
etc etc. Shucks, the beauty of molding composites is that you can make it
any shape you want, in less time, and make it *strong*. Get the material
to work for you, not against you.

Not that I'm an expert or anything, but I've made a lot of stuff out of
epoxy resin added to various other materials... including carbon fiber...
over the years.

Fresh Breezes- Doug King

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

In general,

In hand laid structures, edges and seams should be buried.
(the deeper the better)

The components (layers) are weakest in peal loads - at the edges.
So a smaller layer on top of a larger one might be expected to peal off?

All that takes is breaking an edge loose and letting it work for a while.



YMMV

Richard

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

(corrected to bottom posting to preserve teh thread)

If you go from the smallest piece first you have a chance of trapping
concentric rings or squares of bubbles in the laminate. Sam


wrote:

Can you explain a bit more on your observation of this problem? I
don't quite follow you.

Thanks.

Jay Chan


You need to try it to see for yourself.

Bubbles are bad.

The are air spaces inside the laminate.

Not good for dimensional stability - or strength :(

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

DSK and Brian gave me a weird idea...

Those white plastic shrink-on covers on the new boats..

I wonder if that stuff would be stiff enough to lay-up a glass hull?
Strong back and transom and shrink wrapped hull form?


Might be a cheap way to lay up a hull?

Richard

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

You mean like using a boat as a male form and the shrink wrap plastic as a
mold release? Boats have been used as male forms before, but I can't say
that I've seen anybody using plastic as a mold release. Generally, the
lay-up needs to be flexible or in more than one part however, else you may
not get it off the form. Mold release or not. Be sure to take pix!

Brian D


"cavelamb" wrote in message
k.net...
DSK and Brian gave me a weird idea...

Those white plastic shrink-on covers on the new boats..

I wonder if that stuff would be stiff enough to lay-up a glass hull?
Strong back and transom and shrink wrapped hull form?


Might be a cheap way to lay up a hull?

Richard

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

cavelamb wrote:
(corrected to bottom posting to preserve teh thread)

If you go from the smallest piece first you have a chance of trapping
concentric rings or squares of bubbles in the laminate. Sam


wrote:

Can you explain a bit more on your observation of this problem? I
don't quite follow you.

Thanks.

Jay Chan


You need to try it to see for yourself.

Bubbles are bad.

The are air spaces inside the laminate.

Not good for dimensional stability - or strength :(

But why putting the smallest piece first will increase the chance of
having air bubbles inside the laminate?

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

For strength, there needs to be a high ratio of glass to epoxy, thus one
squeegies (sp?) out as much resin as possible. If the selved edge of the
narrow piece creates a step that wasn't sanded down, the wider layer of
glass will bridge the step and the space under the bridge will be filled
with air. That's why the plastic sheet overlay is so effective.

Roger

http://home.insightbb.com/~derbyrm

wrote in message
ups.com...
cavelamb wrote:
(corrected to bottom posting to preserve teh thread)

If you go from the smallest piece first you have a chance of trapping
concentric rings or squares of bubbles in the laminate. Sam


wrote:

Can you explain a bit more on your observation of this problem? I
don't quite follow you.

Thanks.

Jay Chan


You need to try it to see for yourself.

Bubbles are bad.

The are air spaces inside the laminate.

Not good for dimensional stability - or strength :(

But why putting the smallest piece first will increase the chance of
having air bubbles inside the laminate?

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

Makes sense, but note that the gap can also be filled with thickened epoxy
mixes. If you are being religious about it, you'd use glass microfibers
plus silica (to make the mix nonsagging.) If you are going with the
wet-on-wet approach, then the outer layers of glass tend to press down those
selvage edges and what's not entirely pressed down will typically fill with
epoxy anyway ...and you can spot and fill bubbles (syringe) after curing as
well. But if allowing each layer of tape to cure prior to applying the
next, then the thing to do is to use a carbide scraper (plus light sanding)
to taper the selvage edge nicely AND fill the remaining 'gap' (as you call
it) with thickened epoxy. Most people will just use phenolic microballoon
or glass microsphere mixes for this, but like I said, if you were entirely
anal about it, you'd use glass minifibers and silica to fill the gap with
something that has a bit more tensile strength. But IMHO, using glass
minifibers and silica would be ENTIRELY unnecessary. If the structure is
weak enough to gain from such techniques, then you've already blown it and
should re-think your engineering anyway.

Brian D


"derbyrm" wrote in message
m...
For strength, there needs to be a high ratio of glass to epoxy, thus one
squeegies (sp?) out as much resin as possible. If the selved edge of the
narrow piece creates a step that wasn't sanded down, the wider layer of
glass will bridge the step and the space under the bridge will be filled
with air. That's why the plastic sheet overlay is so effective.

Roger

http://home.insightbb.com/~derbyrm

wrote in message
ups.com...
cavelamb wrote:
(corrected to bottom posting to preserve teh thread)

If you go from the smallest piece first you have a chance of trapping
concentric rings or squares of bubbles in the laminate. Sam


wrote:

Can you explain a bit more on your observation of this problem? I
don't quite follow you.

Thanks.

Jay Chan


You need to try it to see for yourself.

Bubbles are bad.

The are air spaces inside the laminate.

Not good for dimensional stability - or strength :(

But why putting the smallest piece first will increase the chance of
having air bubbles inside the laminate?

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

I screwed up on my first boat with the wide over narrow, wet on wet. Now I
use the plastic overlay and avoid almost all the effort you describe while
still getting a high glass/epoxy ratio for taped joins. It doesn't really
matter which goes on first anymore.

Roger

http://home.insightbb.com/~derbyrm

"Brian D" wrote in message
. ..
Makes sense, but note that the gap can also be filled with thickened epoxy
mixes. If you are being religious about it, you'd use glass microfibers
plus silica (to make the mix nonsagging.) If you are going with the
wet-on-wet approach, then the outer layers of glass tend to press down
those selvage edges and what's not entirely pressed down will typically
fill with epoxy anyway ...and you can spot and fill bubbles (syringe)
after curing as well. But if allowing each layer of tape to cure prior to
applying the next, then the thing to do is to use a carbide scraper (plus
light sanding) to taper the selvage edge nicely AND fill the remaining
'gap' (as you call it) with thickened epoxy. Most people will just use
phenolic microballoon or glass microsphere mixes for this, but like I
said, if you were entirely anal about it, you'd use glass minifibers and
silica to fill the gap with something that has a bit more tensile
strength. But IMHO, using glass minifibers and silica would be ENTIRELY
unnecessary. If the structure is weak enough to gain from such
techniques, then you've already blown it and should re-think your
engineering anyway.

Brian D


"derbyrm" wrote in message
m...
For strength, there needs to be a high ratio of glass to epoxy, thus one
squeegies (sp?) out as much resin as possible. If the selved edge of the
narrow piece creates a step that wasn't sanded down, the wider layer of
glass will bridge the step and the space under the bridge will be filled
with air. That's why the plastic sheet overlay is so effective.

Roger

http://home.insightbb.com/~derbyrm

wrote in message
ups.com...
cavelamb wrote:
(corrected to bottom posting to preserve teh thread)

If you go from the smallest piece first you have a chance of trapping
concentric rings or squares of bubbles in the laminate. Sam


wrote:

Can you explain a bit more on your observation of this problem? I
don't quite follow you.

Thanks.

Jay Chan


You need to try it to see for yourself.

Bubbles are bad.

The are air spaces inside the laminate.

Not good for dimensional stability - or strength :(

But why putting the smallest piece first will increase the chance of
having air bubbles inside the laminate?

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

I'll have to try the plastic overlay approach sometime... it sounds
interesting.

Brian


"derbyrm" wrote in message
m...
I screwed up on my first boat with the wide over narrow, wet on wet. Now I
use the plastic overlay and avoid almost all the effort you describe while
still getting a high glass/epoxy ratio for taped joins. It doesn't really
matter which goes on first anymore.

Roger

http://home.insightbb.com/~derbyrm

"Brian D" wrote in message
. ..
Makes sense, but note that the gap can also be filled with thickened
epoxy mixes. If you are being religious about it, you'd use glass
microfibers plus silica (to make the mix nonsagging.) If you are going
with the wet-on-wet approach, then the outer layers of glass tend to
press down those selvage edges and what's not entirely pressed down will
typically fill with epoxy anyway ...and you can spot and fill bubbles
(syringe) after curing as well. But if allowing each layer of tape to
cure prior to applying the next, then the thing to do is to use a carbide
scraper (plus light sanding) to taper the selvage edge nicely AND fill
the remaining 'gap' (as you call it) with thickened epoxy. Most people
will just use phenolic microballoon or glass microsphere mixes for this,
but like I said, if you were entirely anal about it, you'd use glass
minifibers and silica to fill the gap with something that has a bit more
tensile strength. But IMHO, using glass minifibers and silica would be
ENTIRELY unnecessary. If the structure is weak enough to gain from such
techniques, then you've already blown it and should re-think your
engineering anyway.

Brian D


"derbyrm" wrote in message
m...
For strength, there needs to be a high ratio of glass to epoxy, thus one
squeegies (sp?) out as much resin as possible. If the selved edge of
the narrow piece creates a step that wasn't sanded down, the wider layer
of glass will bridge the step and the space under the bridge will be
filled with air. That's why the plastic sheet overlay is so effective.

Roger

http://home.insightbb.com/~derbyrm

wrote in message
ups.com...
cavelamb wrote:
(corrected to bottom posting to preserve teh thread)

If you go from the smallest piece first you have a chance of
trapping
concentric rings or squares of bubbles in the laminate. Sam


wrote:

Can you explain a bit more on your observation of this problem? I
don't quite follow you.

Thanks.

Jay Chan


You need to try it to see for yourself.

Bubbles are bad.

The are air spaces inside the laminate.

Not good for dimensional stability - or strength :(

But why putting the smallest piece first will increase the chance of
having air bubbles inside the laminate?

Jay Chan

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

dog wrote:
This is rather bad advice. In almost all cases, you WANT THE RESIN AND
PATCH TO BOND TO THE CORE. Putting plastic between the core and the
resin leaves a void too, just not one filled with gasses. Most cores
DO NOT react to Epoxy by dissolving and gassing off... especially if
the core is a good end-grain balsa, which it is on the better boats.

Not tostart an argument, but there are many foams to choose from and
some are lighter & stronger than balsa.

... If the core is not bonded to the repaired area, you have
effectively created a section that is pre-delaminated.

Yeah, that was kind of what I thought too. But you have to keep in
mind, everybody wants something different.

DSK

Yes, there are many foams to choose from, but few have the same
characteristics that make end-grain balsa such a good core material.
Few of the foams bond and wick epoxy resin as well as end-grain balsa.
Few of the foams have the compressive and sheer strength and resistance
that end-grain balsa has. Few of the foams have the high temperature
resistance to softening and deforming that balsa has. To date, nothing
that I have seen is better than a good end-grain balsa for most
applications. There are a few high-tech honeycomb materials that are
almost as good, but they're generally far more expensive and difficult
to work with than end-grain balsa.

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

dog wrote:
Yes, there are many foams to choose from, but few have the same
characteristics that make end-grain balsa such a good core material.
Few of the foams bond and wick epoxy resin as well as end-grain balsa.

Are you looking for bond strength / peel resistance? Some
foams are better in this regard.


Few of the foams have the compressive and sheer strength and resistance
that end-grain balsa has.

Now that's just plain wrong, it is very easy to find foam
that is better in these characteristics. The question is,
can you find better foam that is still lighter, and also
doesn't cost a lot more?

Look into the specs on foam in the 20# and up range.


... Few of the foams have the high temperature
resistance to softening and deforming that balsa has.

Considering the temp characteristics of epoxy, I don't think
this makes much difference. OTOH it is possible to use
fire-retardant foams... balsa is wood after all, and will burn.


... To date, nothing
that I have seen is better than a good end-grain balsa for most
applications.

That statement leads me to wonder how far you've looked.

... There are a few high-tech honeycomb materials that are
almost as good, but they're generally far more expensive and difficult
to work with than end-grain balsa.

It's true that balsa is relatively inexpensive and easy to
work with. I like it... but for my ownpersonal super boat
project, I picked a type of foam that a friend used in
airplane kits. Has some drawbacks, but I have no doubt that
it will be lighter and stronger than balsa... and it won't
ever ever ever rot.

Fresh Breezes- Doug King

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

Brian D wrote:
You mean like using a boat as a male form and the shrink wrap plastic as a
mold release? Boats have been used as male forms before, but I can't say
that I've seen anybody using plastic as a mold release.

Done it myself. Works like a champ as long as the hull
doesn't have any re-curve that locks the new la-up to the
old hull.

.... Generally, the
lay-up needs to be flexible or in more than one part however, else you may
not get it off the form. Mold release or not.

Bingo!

... Be sure to take pix!


And post links to them here. It always makes the day a
little better to see what other people are up to.

DSK

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

dog wrote:

Yes, there are many foams to choose from, but few have the same
characteristics that make end-grain balsa such a good core material.
Few of the foams bond and wick epoxy resin as well as end-grain balsa.

What a crock of crap.

The only time someone uses balsa as a core material on a boat is
because they don't know any better or can't afford anything else.

Lew

Largest Piece Or Smallest Piece First When Laying Fiberglass Cloth Over a Tapered Edge?
 

What Lew said.

"Lew Hodgett" wrote in message
ink.net...
dog wrote:

Yes, there are many foams to choose from, but few have the same
characteristics that make end-grain balsa such a good core material.
Few of the foams bond and wick epoxy resin as well as end-grain balsa.

What a crock of crap.

The only time someone uses balsa as a core material on a boat is
because they don't know any better or can't afford anything else.

Lew

Largest Piece Or Smallest Piece First When Laying FiberglassCloth Over a Tapered Edge?
 

Jim Conlin wrote:
What Lew said.


What I like is the tactful way he says it

DSK