I'm having trouble covering some plywood with fiberglass cloth. The problem
is that I want to be able to see the wood under the cloth, but the cloth
just doesn't seem to want to get "transparent". I've covered plywood before
using this method, including a wooden kayak, and it usually comes out great.
I've been able to sheath the foredeck of the boat successfully, and the
fiberglass "disappears" into the epoxy resin, but for some reason all of a
sudden I'm having problems. It gets about 90% transparent, but stays a
little milky. I've made sure that I lay the cloth onto a wet piece of
plywood, and that I force more epoxy into the weave, but still it looks only
partially transparent. Ideas?

Thanks,
Bill L.

On Tue, 29 May 2007 00:05:37 GMT, "William Longyard"
wrote:

I'm having trouble covering some plywood with fiberglass cloth. The problem
is that I want to be able to see the wood under the cloth, but the cloth
just doesn't seem to want to get "transparent". I've covered plywood before
using this method, including a wooden kayak, and it usually comes out great.
I've been able to sheath the foredeck of the boat successfully, and the
fiberglass "disappears" into the epoxy resin, but for some reason all of a
sudden I'm having problems. It gets about 90% transparent, but stays a
little milky. I've made sure that I lay the cloth onto a wet piece of
plywood, and that I force more epoxy into the weave, but still it looks only
partially transparent. Ideas?

Thanks,
Bill L.

Off the top guesses:
fiberglass prepared for polyester resin
or
humid day.
??

Brian W

Hi Brian,
It's not humidity, so maybe the wrong cloth? I'll look into that.

Thanks,
Bill Longyard

"Brian Whatcott" wrote in message
news
On Tue, 29 May 2007 00:05:37 GMT, "William Longyard"
wrote:

I'm having trouble covering some plywood with fiberglass cloth. The
problem
is that I want to be able to see the wood under the cloth, but the cloth
just doesn't seem to want to get "transparent". I've covered plywood
before
using this method, including a wooden kayak, and it usually comes out
great.
I've been able to sheath the foredeck of the boat successfully, and the
fiberglass "disappears" into the epoxy resin, but for some reason all of a
sudden I'm having problems. It gets about 90% transparent, but stays a
little milky. I've made sure that I lay the cloth onto a wet piece of
plywood, and that I force more epoxy into the weave, but still it looks
only
partially transparent. Ideas?

Thanks,
Bill L.

Off the top guesses:
fiberglass prepared for polyester resin
or
humid day.
??

Brian W

William Longyard wrote:

Hi Brian,
It's not humidity, so maybe the wrong cloth? I'll look into that.

I'm with Brian, check the glass.

Try a piece on some scrap. See what happens.

Lew

On Tue, 29 May 2007 00:05:37 GMT, "William Longyard"
wrote:

I'm having trouble covering some plywood with fiberglass cloth. The problem
is that I want to be able to see the wood under the cloth, but the cloth
just doesn't seem to want to get "transparent". I've covered plywood before
using this method, including a wooden kayak, and it usually comes out great.
I've been able to sheath the foredeck of the boat successfully, and the
fiberglass "disappears" into the epoxy resin, but for some reason all of a
sudden I'm having problems. It gets about 90% transparent, but stays a
little milky. I've made sure that I lay the cloth onto a wet piece of
plywood, and that I force more epoxy into the weave, but still it looks only
partially transparent. Ideas?

Thanks,
Bill L.


If you using epoxy and the cloth doesn't disappear then it is likely
that you have cloth made for use with polyester.

Bruce in Bangkok
(brucepaigeatgmaildotcom)

--
Posted via a free Usenet account from http://www.teranews.com

Glass heavier than 6-8 oz. will not go clear in epoxy. If you need a
heavier layup for structural reasons, a clear finish is out.
Glass cloth has a 'sizing' treatment that is sometimes specific to a
particular type of resin. Ask your vendor if that glass is intended for use
with epoxy.

"William Longyard" wrote in message
link.net...
I'm having trouble covering some plywood with fiberglass cloth. The
problem
is that I want to be able to see the wood under the cloth, but the cloth
just doesn't seem to want to get "transparent". I've covered plywood
before
using this method, including a wooden kayak, and it usually comes out
great.
I've been able to sheath the foredeck of the boat successfully, and the
fiberglass "disappears" into the epoxy resin, but for some reason all of a
sudden I'm having problems. It gets about 90% transparent, but stays a
little milky. I've made sure that I lay the cloth onto a wet piece of
plywood, and that I force more epoxy into the weave, but still it looks
only
partially transparent. Ideas?

Thanks,
Bill L.

"Jim Conlin" writes:

Glass heavier than 6-8 oz. will not go clear in epoxy. If you need a
heavier layup for structural reasons, a clear finish is out.
Glass cloth has a 'sizing' treatment that is sometimes specific to a
particular type of resin. Ask your vendor if that glass is intended for use
with epoxy.

I don't know what 6-8 oz is in real units but here is a 21 year
old boat that has some 360 g/sqm of UDWR glass in epoxy on each
side of the Western Red Cedar. Looks OK to me but your mileage
may vary.

http://hem.bredband.net/b262106/Boat/juguete.html
and
http://hem.bredband.net/b262106/Boat/build.html

I think the OP's problem is contaminated glass.

--
Martin Schöön "Problems worthy of attack
show their worth by hitting back."
Piet Hein

360 g/m^2 is about 10.6 oz/yd^2. You did well with it. Nice work.
I agree that the more probable problem is contamination /sizing.

"Martin Schöön" wrote in message
...
"Jim Conlin" writes:

Glass heavier than 6-8 oz. will not go clear in epoxy. If you need a
heavier layup for structural reasons, a clear finish is out.
Glass cloth has a 'sizing' treatment that is sometimes specific to a
particular type of resin. Ask your vendor if that glass is intended for
use
with epoxy.

I don't know what 6-8 oz is in real units but here is a 21 year
old boat that has some 360 g/sqm of UDWR glass in epoxy on each
side of the Western Red Cedar. Looks OK to me but your mileage
may vary.

http://hem.bredband.net/b262106/Boat/juguete.html
and
http://hem.bredband.net/b262106/Boat/build.html

I think the OP's problem is contaminated glass.

--
Martin Schöön "Problems worthy of attack
show their worth by hitting back."
Piet Hein

William Longyard wrote:
I'm having trouble covering some plywood with fiberglass cloth. The problem
is that I want to be able to see the wood under the cloth, but the cloth
just doesn't seem to want to get "transparent". I've covered plywood before
using this method, including a wooden kayak, and it usually comes out great.
I've been able to sheath the foredeck of the boat successfully, and the
fiberglass "disappears" into the epoxy resin, but for some reason all of a
sudden I'm having problems. It gets about 90% transparent, but stays a
little milky. I've made sure that I lay the cloth onto a wet piece of
plywood, and that I force more epoxy into the weave, but still it looks only
partially transparent. Ideas?

Thanks,
Bill L.


How can you tell if it is prepared for polyester or not? Make up a
sample and try to rip if off the substrate?
I ran into an adhesion problem a while ago and I'm now wondering if the
glass I got was prepared for polyester and I didn't know it. After
laminating two layers of 6 oz fabric on my cockpit sole, I was able to
tear the epoxy up with me hands. I was also able to rip the two layers
of glass apart. Maybe this is what happened. Hmm..

""Martin Schöön"" wrote in message
...
"Jim Conlin" writes:

Glass heavier than 6-8 oz. will not go clear in epoxy.



I don't know what 6-8 oz is in real units but here is a 21 year
old boat that has some 360 g/sqm of UDWR glass in epoxy on each
side of the Western Red Cedar. Looks OK to me but your mileage
may vary.

I think the OP's problem is contaminated glass.

--
Martin Schöön

33 g/sg m is about 1 oz.
Hence 360g/sqm is about 11 oz cloth.

Peter HK