Epoxy Resin/Fiberglass Tape: Milky Areas?
 

Just finished applying about 40 feet of 1" fiberglass tape to a surf ski's
(long, skinny sit-on-top kayak...) hull/deck seam using West System epoxy resin.

99" of it went as expected, but I've got a few areas (2" max) where the
resin/tape is milky white. In the longest area, it was uniform from one edge
of the tape to the other. In the smaller areas it doesn't extend the full
width of the tape.

I guess I'm going to grind it off once it's cured and try another layer,
but the suspected cause will determine how I go about applying subsequent
layers.

Water weeping from the seam? Contaminated tape?

Something else?
--
PeteCresswell

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

(PeteCresswell) wrote:

Water weeping from the seam?

That's possible, as it would turn uncured epoxy milky.

Contaminated tape?

Possible, but unlikely unless it was laying around or you cut it on an
unclean surface.

Something else?

Air bubbles. Squeegeeing too hard can drive micro-fine air bubbles into
the resin. Your technique will dictate whether that's even a possible
cause.

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

If the apllication of a little more resin can saturate the glass and its
bond with the substrate, you can salvage the job without removing the glass.
Test with a wet rag of acetone to see whether a liquid can flow through the
applied glass and saturate it./ If so, warm it well with a hair dryer or
heat lamp before brushing on a bit more resin. Warmth makes the resin flow
more easily.
If the acetone rag doesn't saturate the glass, the glass has to be removed.
If it hasn't cured too much, a sharp chisel would be the first tool i'd try.



"(PeteCresswell)" wrote in message
...
Just finished applying about 40 feet of 1" fiberglass tape to a surf ski's
(long, skinny sit-on-top kayak...) hull/deck seam using West System epoxy
resin.

99" of it went as expected, but I've got a few areas (2" max) where the
resin/tape is milky white. In the longest area, it was uniform from one
edge
of the tape to the other. In the smaller areas it doesn't extend the
full
width of the tape.

I guess I'm going to grind it off once it's cured and try another layer,
but the suspected cause will determine how I go about applying subsequent
layers.

Water weeping from the seam? Contaminated tape?

Something else?
--
PeteCresswell

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

Pete,
Sounds like an 'epoxy starved' area, to me. Either not enough epoxy
UNIFORMLY applied to begin with, or an area rolled/squeegeed to hard and the
epoxy pushed away. To avoid this I usually apply in 2 to 3 'steps . . .
a} with raw wood - I put on a coat of unthickened epoxy and let it cure . .
.. then cut parts. b}With repairs or applying cloth to a hull . . . apply a
coat of unthickened epoxy and allow it to 'set' - from just when it looses
it's tackiness, to the 'green' stage.
c}Lay out the cloth/tape . . holding it in place with 'thumb pins' or
masking tape, and apply epoxy mixed with a bit of fumed silica as a
thixotopic agent - more then a little if it will be painted or I don't need
a Clear finish.

Regards,
Ron Magen
Backyard Boatshop

"(PeteCresswell)" wrote in message
...
Just finished applying about 40 feet of 1" fiberglass tape to a surf ski's
(long, skinny sit-on-top kayak...) hull/deck seam using West System epoxy
resin.

99" of it went as expected, but I've got a few areas (2" max) where the
resin/tape is milky white. In the longest area, it was uniform from one
edge
of the tape to the other. In the smaller areas it doesn't extend the
full
width of the tape.

I guess I'm going to grind it off once it's cured and try another layer,
but the suspected cause will determine how I go about applying subsequent
layers.

Water weeping from the seam? Contaminated tape?

Something else?
--
PeteCresswell

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

Per Ron Magen:
Sounds like an 'epoxy starved' area, to me. Either not enough epoxy
UNIFORMLY applied to begin with, or an area rolled/squeegeed to hard and the
epoxy pushed away. To avoid this I usually apply in 2 to 3 'steps . . .
a} with raw wood - I put on a coat of unthickened epoxy and let it cure . .
. then cut parts. b}With repairs or applying cloth to a hull . . . apply a
coat of unthickened epoxy and allow it to 'set' - from just when it looses
it's tackiness, to the 'green' stage.

I guess I could try the following - but it would take a day or two with 12-hour
cure times.....

Can I paint the surface with a thin coat of epoxy, smooth on the cloth, let it
cure, and then squeegee more epoxy over top to completely saturate the cloth?
This would be a nice solution to some situations where the edges of the cloth
want to curl up because of curves in the surface - tack one side down, tack the
other side down, then saturate.
--
PeteCresswell

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

Each time I've had that problem, it's been air under the epoxy. I've ground
it down, BUT don't get the dust from the glass in your clothes unless you're
going to wash and wash and wash them. (Tyvek coveralls?) The "epoxy itch"
does go away in a few days, and it's not fatal, but you really don't want
it.

12 hour cure times don't compute for me. In fact, I don't even let the
first coat lose its tackiness. I think it's just to satisfy the tendency of
the wood to leach epoxy out of the joint/tape. Once the underlayment is
saturated, it's ready for the glass. (I guess if the first coat is tacky,
it will be harder to reposition the tape, but sometimes that's an advantage.
Messy, but you are wearing latex gloves?)

One trick I use on bare wood is to play the heat gun* over the wood just
before applying the epoxy. The air in the wood will then contract and pull
the epoxy down into the pores. If the wood is colder than the cure
temperature of the epoxy (it's exothermic, remember) then small bubbles will
form and try to rise thru the epoxy, discoloring it (white) and making
craters.

* Black & Decker, about $20, don't char the wood -- also good for heat
shrink tubing and paint stripping

Roger

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

"(PeteCresswell)" wrote in message
...
Per Ron Magen:
Sounds like an 'epoxy starved' area, to me. Either not enough epoxy
UNIFORMLY applied to begin with, or an area rolled/squeegeed to hard and
the
epoxy pushed away. To avoid this I usually apply in 2 to 3 'steps . . .
a} with raw wood - I put on a coat of unthickened epoxy and let it cure .
.
. then cut parts. b}With repairs or applying cloth to a hull . . . apply a
coat of unthickened epoxy and allow it to 'set' - from just when it looses
it's tackiness, to the 'green' stage.

I guess I could try the following - but it would take a day or two with
12-hour
cure times.....

Can I paint the surface with a thin coat of epoxy, smooth on the cloth,
let it
cure, and then squeegee more epoxy over top to completely saturate the
cloth?
This would be a nice solution to some situations where the edges of the
cloth
want to curl up because of curves in the surface - tack one side down,
tack the
other side down, then saturate.
--
PeteCresswell

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

Pete . . .
'read' between the line . . .

"(PeteCresswell)" wrote in message
...
Per Ron Magen:
Sounds like an 'epoxy starved' area, to me.
SNIP

I guess I could try the following - but it would take a day or two with
12-hour
cure times.....
Not really -

Can I paint the surface with a thin coat of epoxy, smooth on the cloth,
let it
cure, . . .
NO - Neine - Nict . . . Do NOT let it cure before adding the 'fill coat'
or you will have the SAME problem {Did I mention you are going to HAVE
to cut out and feather the 'starved' parts}

and then squeegee more epoxy over top to completely saturate the cloth?
This would be a nice solution to some situations where the edges of the
cloth
want to curl up because of curves in the surface - tack one side down,
tack the
other side down, then saturate.

Try . . . 'paint' ENTIRE surface with unthickened epoxy{then let set, or
'heat accelerate' till tackiness gone, or immediately proceed on 'wet'
epoxy - your choice}, then UNROLL the glass tape into the epoxy. Use a stiff
disposable 'chip' brush to DAB it into the epoxy and use pins where it
starts to slip - pinning it in place as you go. Mix up another batch of
epoxy - unthickened, or slightly thickened - and dab it or GENTLY brush it
on to saturate the cloth WITHOUT getting runs, 'curtaining', or sags in the
cloth.

Either way, a few hours should do it - unless your ambient is around 40
degrees F.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

--
PeteCresswell

Epoxy Resin/Fiberglass Tape: Milky Areas?
 

@#@

Milky white indicates an area that has contamination mild acids etc will do
this. Just cut the piece out clean with acetone and redo, no big deal.

Ray
"(PeteCresswell)" wrote in message
...
Just finished applying about 40 feet of 1" fiberglass tape to a surf ski's
(long, skinny sit-on-top kayak...) hull/deck seam using West System epoxy
resin.

99" of it went as expected, but I've got a few areas (2" max) where the
resin/tape is milky white. In the longest area, it was uniform from one
edge
of the tape to the other. In the smaller areas it doesn't extend the
full
width of the tape.

I guess I'm going to grind it off once it's cured and try another layer,
but the suspected cause will determine how I go about applying subsequent
layers.

Water weeping from the seam? Contaminated tape?

Something else?
--
PeteCresswell