John,

The numbers you quote are (again) for a repair done under ideal
conditions.

Please use whatever materials you choose to do the repairs on YOUR boat.
I/we have a reputation to maintain and can not afford to work on the
cheap.

In four plus decades of doing boat repair (I did not start with
plastic), I have had some experience that I care to share so that other
might benefit. As stated below, the epoxy is going to be something like
5~7% of the job cost. - I still don't know why you pay more than the
retail price for epoxy. Try going to Boat/West they will have adeal for
you.

I have had to clean up after too many mix failures with poly and have
never had one with epoxy run from a pump set. We even used to mix poly
on a balanace, and we still had a crash set. I have had to repair
numerous bond failures (never my own) in poly assemblies (as described
prior).

I assign no supernatural powers to epoxy. I mearly state that it is a
much better material for the DYI owner repair.

My own personal sloop is the first of its class (hull#1). It is
twenty-four years old. It is still competitive and I am expecting it to
be my last boat.

The repairs the out friend Michiel is outlining are about 5mh/ft2 and he
could lose a lot of that if he has a mix or bond failure. I don't like
to give work away.

Matt Colie

John M wrote:
Matt:
Some figures taken from West Epoxy web site where they did tests on bonding
strength of epoxy and polyester.
Tensile strength of original glass 26,198 PSI
Tensile strength of poly repair 18,460 PSI
Tensile of epoxy repair 21,404 PSI
Therefore polyester has a strength 13% less than epoxy at a cost of about
500% more.

"Matt Colie" wrote in message
...

John,

Any part, piece -whatever of any racing yacht can fail at any time, I
mentioned "Tomahawk" because I knew some of the cast involved and it was a
polyester bond that failed in this case and caused the loss of the vessel.


The way many boats are built today anything can fall off.


I agree that there is no substitute for proper practice.

My problem with polyester is simple, the bond strength is poor. If you
can do it all as a wet assembly, that is fine, but if you need to put
pieces together - polyester can be problems. I have done whole boats with
poly and vinylester (which is another animal). I completely agree that it
has its place. Most of them are in a mold.


See the beginning paragraph 13% difference.


If a guy is going to work under less than ideal conditions and do small
patches (less than a mold section), I always that they look at the
additional cost of epoxy. If you could get p or vest resin that had nice
little measuring pumps and was as well behaved, I still would be hard
pressed to advise it for repairs.


Polyester isn't that fussy but I use a Nalge dispenser and never had a
problem.



At the prices I pay 5 gallons (the smallest we buy) of poly is about
85$us, vinyl is about 140$us and 250$us for gallon mix - includes harder
of epoxy. The way any job works, labor is the big cost and the labor to
use gallons of resin is a big number.

The only problem with epoxy for repairs that require cosmetic surfacing is
taht you have to do a intermediate coat of vinyl to bond the polyester
gelcoat to the epoxy. Gelcoat will just fall right out of an epoxy
patch - given half a chance - it will has been know to do the same to a
poly repair but vinylester is good enough to bond the two.

And - when it come to the failures of super-lights - I don't even count
them as real. Like the ICAA boat that folded and sank off San Diego.
There is a reason why the shipwrights that I knew as a child worked the
way that they did. I have come to understand that all the wouldful new
analysis stuff like FEA, CFD and such are nice, but the people that have
been out there better not use it to determine what the sea can do.

Matt Colie


My main problem with epoxy is the people who think it's the holy grail,
I think anyone who
recommends epoxy to repair a deck on a 25 year old 20 foot boat has either
too much money or has been reading too many newsgroups.
I would think that the boat that started this discussion could be repaired
at minimum cost and be as strong as the good side of the deck. No more is
needed.
John


John M wrote:

Matt:
Actually I don't do repairs on cars.
You mention Tomahawk and her "polyester patch job" how about the other
five boats that lost their masts or the eight that were damaged or for
that matter the 96 that dropped out. All polyester patches?
There are many boats built down to a price that will have parts falling
off. But think off all the plain old polyester and glass boats that have
been around the world with little or no problems.
Which brings to mind a British catamaran whose name escapes me at
present, that was built for a round the world record attempt in 1999 or
2000. Built of prepreg epoxy, carbon fiber all the latest high tech. On
its first test run in weather that wasn't to bad its bows fell off. I
won't blame the epoxy or carbon fiber.
My point is epoxy and polyester have their place but nothing replaces
proper building practices.
With prices of epoxy at $74 a gallon and polyester at $105 for 5 gallons
it's hard to believe there is only a $200 difference in a $5000 job.
John



"Matt Colie" wrote in message
...


John,

Do you do body repairs with window screen and plastic filler?
You can make it look just as good as steel?

If you would go to sea in a boat patched with polyester, be my guest.
One of the famous ones in the book is "Tomahawk". She sank during a
Bayview Mackinac in the mid 80's. That was a polyester patch job.

A clients mast came down when it buckled at the spreaders because the
tabbing for the anchor for the lower came away from the hull side.

I helped recover a sloop that lost its steering because one of the
turning blocks came adrift.

Those last two were both bond failures of parts installed at teh builders
yard.

We are set up for resin infusion in several versions (skrimp, spike and
texp2) but none are well suited to most non-molded assemblies (that most
repairs).

Epoxy is used in repairs for two reasons, it has cohesive and adhesive
bond properties that far exceed that of poly or vinylesters. We
specialize in fixing things - once. Our clients only talk to us if they
want a first class job. We clould save the client 1or 200$ on a 5k$ job
by using cheap materials. We use only epoxy.

You can do what you want, but some of are not interested in doing it ont
he cheap - cheap is the price of low value.

Matt Colie

John M wrote:


Just wondering do you guys that use epoxy for everything also use
titanium for auto body repairs after all it's better than steel. It
seems rather silly to repair a polyester and glass boat which is old
with epoxy and the latest high tech fabrics. Why not try resin infusion
too
John
"Jim Conlin" wrote in message
...



I figure it'd be somewhat over $10/ft^2.
Core-cell $4-
maybe 4 laminations of:
12 oz. knitted Glass $10/yd = $.80/ft^2/ply
epoxy $70/gal = $.60/ft^2/ply

paint $1/ft^2
plus abrasives, peel ply, fillers, vacuum bag consumables


"DSK" wrote in message
.net...



Lew Hodgett wrote:



You haven't priced materials lately, have you?

Think OIL.


Actually, I have- am buying materials for a carbon fiber
rowing dinghy. But I think you grossly (very grossly)
overestimated the cost & amount of materials needed for
replacing core on a 20' deck.

It's not going to be free, that's not what I'm saying.

DSK

Michiel,
Discussion is always valuable. As I often remark (to clients that find
the proposal that they have just received to be overwhelming), thinking
is the cheapest and most valuable thing to do.

In the time this discussion has ben on the wire, I have contracted to do
a very similar job. I will gladdly write a quote for this job if you
are in 1hr striking range from the highway exit nearest Detroit River
Light. I do, however, have confidence that the assmebled quote will be
more than you were expecting.

Good Luck with the job, keep us informed.

Matt Colie

Michiel wrote:

Hehe, I had no idea this would set off such a discussion! This is
great stuff.. lots of input. Thanks!

Too bad I can't make you guys fix the boat for me.. I think it would
already be done!

Michiel


On Tue, 29 Nov 2005 21:06:57 -0500, "John M" wrote:


Matt:
Some figures taken from West Epoxy web site where they did tests on bonding
strength of epoxy and polyester.
Tensile strength of original glass 26,198 PSI
Tensile strength of poly repair 18,460 PSI
Tensile of epoxy repair 21,404 PSI
Therefore polyester has a strength 13% less than epoxy at a cost of about
500% more.

"Matt Colie" wrote in message
...

John,

Any part, piece -whatever of any racing yacht can fail at any time, I
mentioned "Tomahawk" because I knew some of the cast involved and it was a
polyester bond that failed in this case and caused the loss of the vessel.

The way many boats are built today anything can fall off.


I agree that there is no substitute for proper practice.

My problem with polyester is simple, the bond strength is poor. If you
can do it all as a wet assembly, that is fine, but if you need to put
pieces together - polyester can be problems. I have done whole boats with
poly and vinylester (which is another animal). I completely agree that it
has its place. Most of them are in a mold.

See the beginning paragraph 13% difference.


If a guy is going to work under less than ideal conditions and do small
patches (less than a mold section), I always that they look at the
additional cost of epoxy. If you could get p or vest resin that had nice
little measuring pumps and was as well behaved, I still would be hard
pressed to advise it for repairs.

Polyester isn't that fussy but I use a Nalge dispenser and never had a
problem.



At the prices I pay 5 gallons (the smallest we buy) of poly is about
85$us, vinyl is about 140$us and 250$us for gallon mix - includes harder
of epoxy. The way any job works, labor is the big cost and the labor to
use gallons of resin is a big number.

The only problem with epoxy for repairs that require cosmetic surfacing is
taht you have to do a intermediate coat of vinyl to bond the polyester
gelcoat to the epoxy. Gelcoat will just fall right out of an epoxy
patch - given half a chance - it will has been know to do the same to a
poly repair but vinylester is good enough to bond the two.

And - when it come to the failures of super-lights - I don't even count
them as real. Like the ICAA boat that folded and sank off San Diego.
There is a reason why the shipwrights that I knew as a child worked the
way that they did. I have come to understand that all the wouldful new
analysis stuff like FEA, CFD and such are nice, but the people that have
been out there better not use it to determine what the sea can do.

Matt Colie


My main problem with epoxy is the people who think it's the holy grail,
I think anyone who
recommends epoxy to repair a deck on a 25 year old 20 foot boat has either
too much money or has been reading too many newsgroups.
I would think that the boat that started this discussion could be repaired
at minimum cost and be as strong as the good side of the deck. No more is
needed.
John


John M wrote:

Matt:
Actually I don't do repairs on cars.
You mention Tomahawk and her "polyester patch job" how about the other
five boats that lost their masts or the eight that were damaged or for
that matter the 96 that dropped out. All polyester patches?
There are many boats built down to a price that will have parts falling
off. But think off all the plain old polyester and glass boats that have
been around the world with little or no problems.
Which brings to mind a British catamaran whose name escapes me at
present, that was built for a round the world record attempt in 1999 or
2000. Built of prepreg epoxy, carbon fiber all the latest high tech. On
its first test run in weather that wasn't to bad its bows fell off. I
won't blame the epoxy or carbon fiber.
My point is epoxy and polyester have their place but nothing replaces
proper building practices.
With prices of epoxy at $74 a gallon and polyester at $105 for 5 gallons
it's hard to believe there is only a $200 difference in a $5000 job.
John



"Matt Colie" wrote in message
...


John,

Do you do body repairs with window screen and plastic filler?
You can make it look just as good as steel?

If you would go to sea in a boat patched with polyester, be my guest.
One of the famous ones in the book is "Tomahawk". She sank during a
Bayview Mackinac in the mid 80's. That was a polyester patch job.

A clients mast came down when it buckled at the spreaders because the
tabbing for the anchor for the lower came away from the hull side.

I helped recover a sloop that lost its steering because one of the
turning blocks came adrift.

Those last two were both bond failures of parts installed at teh builders
yard.

We are set up for resin infusion in several versions (skrimp, spike and
texp2) but none are well suited to most non-molded assemblies (that most
repairs).

Epoxy is used in repairs for two reasons, it has cohesive and adhesive
bond properties that far exceed that of poly or vinylesters. We
specialize in fixing things - once. Our clients only talk to us if they
want a first class job. We clould save the client 1or 200$ on a 5k$ job
by using cheap materials. We use only epoxy.

You can do what you want, but some of are not interested in doing it ont
he cheap - cheap is the price of low value.

Matt Colie

John M wrote:


Just wondering do you guys that use epoxy for everything also use
titanium for auto body repairs after all it's better than steel. It
seems rather silly to repair a polyester and glass boat which is old
with epoxy and the latest high tech fabrics. Why not try resin infusion
too
John
"Jim Conlin" wrote in message
...



I figure it'd be somewhat over $10/ft^2.
Core-cell $4-
maybe 4 laminations of:
12 oz. knitted Glass $10/yd = $.80/ft^2/ply
epoxy $70/gal = $.60/ft^2/ply

paint $1/ft^2
plus abrasives, peel ply, fillers, vacuum bag consumables


"DSK" wrote in message
h.net...



Lew Hodgett wrote:



You haven't priced materials lately, have you?

Think OIL.


Actually, I have- am buying materials for a carbon fiber
rowing dinghy. But I think you grossly (very grossly)
overestimated the cost & amount of materials needed for
replacing core on a 20' deck.

It's not going to be free, that's not what I'm saying.

DSK

John M wrote:

Matt:
Some figures taken from West Epoxy web site where they did tests on bonding
strength of epoxy and polyester.
Tensile strength of original glass 26,198 PSI
Tensile strength of poly repair 18,460 PSI
Tensile of epoxy repair 21,404 PSI
Therefore polyester has a strength 13% less than epoxy at a cost of about
500% more.

"Matt Colie" wrote in message
...

John,

Any part, piece -whatever of any racing yacht can fail at any time, I
mentioned "Tomahawk" because I knew some of the cast involved and it was a
polyester bond that failed in this case and caused the loss of the vessel.


The way many boats are built today anything can fall off.


I agree that there is no substitute for proper practice.

My problem with polyester is simple, the bond strength is poor. If you
can do it all as a wet assembly, that is fine, but if you need to put
pieces together - polyester can be problems. I have done whole boats with
poly and vinylester (which is another animal). I completely agree that it
has its place. Most of them are in a mold.


See the beginning paragraph 13% difference.


If a guy is going to work under less than ideal conditions and do small
patches (less than a mold section), I always that they look at the
additional cost of epoxy. If you could get p or vest resin that had nice
little measuring pumps and was as well behaved, I still would be hard
pressed to advise it for repairs.


Polyester isn't that fussy but I use a Nalge dispenser and never had a
problem.



At the prices I pay 5 gallons (the smallest we buy) of poly is about
85$us, vinyl is about 140$us and 250$us for gallon mix - includes harder
of epoxy. The way any job works, labor is the big cost and the labor to
use gallons of resin is a big number.

The only problem with epoxy for repairs that require cosmetic surfacing is
taht you have to do a intermediate coat of vinyl to bond the polyester
gelcoat to the epoxy. Gelcoat will just fall right out of an epoxy
patch - given half a chance - it will has been know to do the same to a
poly repair but vinylester is good enough to bond the two.

And - when it come to the failures of super-lights - I don't even count
them as real. Like the ICAA boat that folded and sank off San Diego.
There is a reason why the shipwrights that I knew as a child worked the
way that they did. I have come to understand that all the wouldful new
analysis stuff like FEA, CFD and such are nice, but the people that have
been out there better not use it to determine what the sea can do.

Matt Colie


My main problem with epoxy is the people who think it's the holy grail,
I think anyone who
recommends epoxy to repair a deck on a 25 year old 20 foot boat has either
too much money or has been reading too many newsgroups.
I would think that the boat that started this discussion could be repaired
at minimum cost and be as strong as the good side of the deck. No more is
needed.
John


John M wrote:

Matt:
Actually I don't do repairs on cars.
You mention Tomahawk and her "polyester patch job" how about the other
five boats that lost their masts or the eight that were damaged or for
that matter the 96 that dropped out. All polyester patches?
There are many boats built down to a price that will have parts falling
off. But think off all the plain old polyester and glass boats that have
been around the world with little or no problems.
Which brings to mind a British catamaran whose name escapes me at
present, that was built for a round the world record attempt in 1999 or
2000. Built of prepreg epoxy, carbon fiber all the latest high tech. On
its first test run in weather that wasn't to bad its bows fell off. I
won't blame the epoxy or carbon fiber.
My point is epoxy and polyester have their place but nothing replaces
proper building practices.
With prices of epoxy at $74 a gallon and polyester at $105 for 5 gallons
it's hard to believe there is only a $200 difference in a $5000 job.
John



"Matt Colie" wrote in message
...


John,

Do you do body repairs with window screen and plastic filler?
You can make it look just as good as steel?

If you would go to sea in a boat patched with polyester, be my guest.
One of the famous ones in the book is "Tomahawk". She sank during a
Bayview Mackinac in the mid 80's. That was a polyester patch job.

A clients mast came down when it buckled at the spreaders because the
tabbing for the anchor for the lower came away from the hull side.

I helped recover a sloop that lost its steering because one of the
turning blocks came adrift.

Those last two were both bond failures of parts installed at teh builders
yard.

We are set up for resin infusion in several versions (skrimp, spike and
texp2) but none are well suited to most non-molded assemblies (that most
repairs).

Epoxy is used in repairs for two reasons, it has cohesive and adhesive
bond properties that far exceed that of poly or vinylesters. We
specialize in fixing things - once. Our clients only talk to us if they
want a first class job. We clould save the client 1or 200$ on a 5k$ job
by using cheap materials. We use only epoxy.

You can do what you want, but some of are not interested in doing it ont
he cheap - cheap is the price of low value.

Matt Colie

John M wrote:


Just wondering do you guys that use epoxy for everything also use
titanium for auto body repairs after all it's better than steel. It
seems rather silly to repair a polyester and glass boat which is old
with epoxy and the latest high tech fabrics. Why not try resin infusion
too
John
"Jim Conlin" wrote in message
...



I figure it'd be somewhat over $10/ft^2.
Core-cell $4-
maybe 4 laminations of:
12 oz. knitted Glass $10/yd = $.80/ft^2/ply
epoxy $70/gal = $.60/ft^2/ply

paint $1/ft^2
plus abrasives, peel ply, fillers, vacuum bag consumables


"DSK" wrote in message
.net...



Lew Hodgett wrote:



You haven't priced materials lately, have you?

Think OIL.


Actually, I have- am buying materials for a carbon fiber
rowing dinghy. But I think you grossly (very grossly)
overestimated the cost & amount of materials needed for
replacing core on a 20' deck.

It's not going to be free, that's not what I'm saying.

DSK







All this puts me in mind of patching an old goatskin water bladder
with a piece of new leather.

Also, cost benefit analysis, proper surface preparation, who knows what?

All ties in with chemical bond curing. How about contact cement or
other "primer" over old poly, followed by more poly / glass?

Terry K

Terry
Please note I never said the epoxy repair would not be stronger than the
same in polyester. Lets take this to the extreme and say epoxy is 100 times
stronger and many think this is the case. Why on a 25 year old boat would
anybody want one side to be 100 times stronger than the original deck. I
think I did mention proper workmanship counts which precludes contact
cement.
No doubt Matts repair will be stronger and probably prettier than mine but
strong enough is strong enough.
John

"
All this puts me in mind of patching an old goatskin water bladder with a
piece of new leather.

Also, cost benefit analysis, proper surface preparation, who knows what?

All ties in with chemical bond curing. How about contact cement or other
"primer" over old poly, followed by more poly / glass?

Terry K

Terry K said

All this puts me in mind of patching an old goatskin water
bladder with a piece of new leather.

Also, cost benefit analysis, proper surface preparation, who
knows what?

All ties in with chemical bond curing. How about contact cement
or other "primer" over old poly, followed by more poly / glass?


John M wrote:
Terry
Please note I never said the epoxy repair would not be stronger than the
same in polyester. Lets take this to the extreme and say epoxy is 100 times
stronger and many think this is the case. Why on a 25 year old boat would
anybody want one side to be 100 times stronger than the original deck. I
think I did mention proper workmanship counts which precludes contact
cement.
No doubt Matts repair will be stronger and probably prettier than mine but
strong enough is strong enough.
John


My sentiment, too. With whom are you in dispute?

I am interested in knowing if there might be a primer of some sort
that might improve the mere 13,000 lb(whatever!) per sq inch bond of
poly on poly that is supposedly not sufficient to be trustworthy
when compared to 18,000 (whatever!) epoxy glue.

How did the old guys work up the nerve to trust oakum and white lead
jammed in all those lapstrake planks? Wonder what it's bond strength
was, 10 lbs per sq inch? The nails would each contribute, what, 200
lbs per nail? Could structure and configuration and application have
anything to do with it?

My HR28 seemed quite happy with the approx 9:1 taper, one sided, one
splot, external conical wad patch over a removed 1.5" thru hull
hole, with one layer of glass inside just for worries sake, as per
the Gougeon brothers advice. Of course, the HR was about 1/4" thick
solid glass, and some will say, built like a brick tank to begin
with. (Cobham armour, anyone?)

Neither welded titanium nor epoxy could have performed better in any
imaginable circumstace. After the boat was destroyed by arson and
nearby glass burned and melted, the patch was still unnoticable,
still trustworthy, still about 5 bucks cheaper, still gelcoatable,
if one wanted to gelcoat under bottom paint. Another gold plating
option unexcercised.

I can not see where using a thinner epoxy splot would actually save
any appreciable weight, either. Of course, new construction maxi
racers, engineered all to hell for every imagined marginal advantage
doesn't exactly reccommend itself either, after what seems to happen
to aramid and carbon fibre racing boats exposed to one inch higher
or one knot faster waves and winds than designed up against.

This epoxy thing seems like a sickness, mania, or sales hype to me.

My whacko buddy was rabid about Mission brand speakers being
unarguably, vastly superior while arguing in his commonly
bewildered, strangely motivated state. My test equipment was
irrelevant in that it did not appreciate subjective, sensible colour
of sound, and phase, or something. I simply maintained that the
possible .00001% undetectable "improvement" over my old EPIs was
irrelevant to the application, cost benefit wise, considering the
way premium prices. He went incohate, popped his wads! Too much
meth? Stock in the company? Or, just innocent testosterone?

I would really like to believe, but no epistle has arrived, as yet,
and the light required to see such epistle remains dark.

As far as the material for replacement core is concerned, balsa is
primarily spacer. It's strength really isn't appreciable. Old
plywood scraps is as good or stronger, if a little heavier, if kept
dry. Small pieces, isolated by plasic dams is adequate, at least.

Terry K