Page 1 of 2

8-Harness Satin Weave

Posted: Thu Mar 23, 2006 5:11 pm
by jem
I like to experiment with different thickness of fiberglass and different weave.

My latest adventure was using 8-Harness Satin Weave from U.S. Composites. Scroll down about 1/2 on this page:

It's 9-ounce cloth but I wanted some extra stiffness on the bottom panel of my new canoe. It's very tightly woven but the weave pattern makes it pretty easy to work with. I used on a mostly flat panel. It conforms very nicely but it a PAIN to wet out.

I used a foam roller to apply the resin. Took several passes of going over all the spots to get all the air out and to fully wet the weave. I would not recommend using this cloth is large sections especially of you're working in warm temperatures and need to move quickly. I tried using my grooved roller but had limited results. It was easier just to work the foam roller over the "dry" spots.

It's a very nice looking cloth when cured. Hardly any weave to fill in so that's a plus.

I'd probably use it again but not for a quick lay up.

Posted: Thu Mar 23, 2006 8:46 pm
by Oldsparkey
I like and have faith in the 3.25 tight woven glass but it is a pain to work with and especially to wet out with a foam roller, it takes some doing to get it right and you are using some glass almost three times that, I can understand the problems you had.

Look at the happy side, the bottom of your boat, for better terminology, should be bullet proof.


Posted: Fri Mar 24, 2006 11:20 am
by jem
I have some of the 6-ounce tight weave from RAKA...similar to the 3.25 cloth you use except a heavier thread.

The 6-ounce tight weave has a little bit of a paper-like feel to it. It's pretty stiff. When I use it I have a hard time getting it to wrap around antything more than 30 degrees (internal...or 150 external) or so.

The 8-harness is different. It'll conform to corners well. The biggest problem I had was getting it to wet out and release the air bubbles. The grooved roller didn't do much because the air bubble that got trapped were pretty small.

I did get a higher glass-to-resin ratio out of it. Used just a little bit more resin than I would have using standard weave 6-ounce. But the finished product is much smoother so I'll save the resin I'd have to use for weave fill.

I think if I used a thinner resin (or perhaps warmed up the resin I used) the process might have gone better. I might order some more in the future.

Posted: Fri Mar 24, 2006 1:15 pm
by Oldsparkey
I have diluted the epoxy with a small amount of acetone when saturating the wood prior to putting on the glass.

My thought is ......... Why not mix some acetone in the resin when wetting out the glass this would make the resin thinner, especially for the first coat to get it down on the boat...... Just an idea that I have NOT tried.

Might have to try it on a storage box (wanigan) , something besides a boat.


Posted: Sat Mar 25, 2006 9:15 pm
by Kayak Jack
You guys are better craftsmen than I. My attempt to use a tight weave glass resulted in (at first) a nice job. When I came back an hour later, I was (horrified would be a kind word) torqued off.

I'd laid it on the inside of a canoe, and it did not like being asked to conform to the curves inside a boat. So, it crept around and caused wrinkles all over the bottom of the boat. I was successful in eliminating only a few of them as the epoxy was pretty stiff by that time. I now have a tractionized floor on the canoe.

I'll stick with a looser weave that is more amenable to doing what I ask it to do without throwing a snit fit or even a whimper. I would not recommend a tight weave glass for a beginner, or for a klutz like me.

Posted: Mon Mar 27, 2006 12:00 am
by CC TX
Being a beginner, and not knowing the difference, I had bought some 4 oz. cloth that is very stiff. To make matters even worse, it came folded, and was creased badly. I used it inside and out on the hull. Pictures 53 and 54 shows the creases very well. I bought more of this same cloth; however, I requested this order for the cloth to be rolled. Even though it is stiff, I have gotten use to it, and I like it now.

Some time ago I had thinned epoxy with acetone. It takes very little acetone to make the epoxy thin. It also slows the cure time considerably.

I expect that everyone develops their own techniques; this is some of the things that I have done to make the stiff cloth easier to work with:

When the temperature is below about 70 F, I warm the resin and hardener to around 105 F to 110 F. It makes the epoxy thin, and much easier to work with. Epoxy is very temperature sensitive; if the shop temperature is too cool, the warm epoxy will cool down very fast and get thick; however, if the shop is too warm, it will start setting up and melt your cup. If it starts setting up, it will not wet out the glass. I expect that this will also vary depending on the brand of epoxy and speed of hardener.

I usually apply a thin layer of epoxy to the surface, and then lay the cloth on top of the wet epoxy. I then press the glass down into the epoxy. The glass will almost be completly wet out. I then brush on a light coat of epoxy on top, and squeege any excess off. I get a much higher glass to resin ratio this way. The glass also tends to stay down a liitle better.

If I have an edge of glass that won't stay down, I tape the edge down with plastic electrical tape. It is very surprising that it will stick to the glass even though it is wet with epoxy. After the epoxy sets up, the tape is easy to remove.

Posted: Mon Mar 27, 2006 12:35 am
by lncc63
Sorry guys but I have to ask: Isn't it bad to thin the epoxy with acetone? Does the acetone end up evaporating or does it get integrated into the epoxy?

Just my 2-cents on the glass weave: I can imagine it being difficult to make heavy glass curve around edges. Since we do not have any other option but 6 oz plain woven glass, I've been using 3 layers of it in place of the a specified 12 oz biax. My point here is that it is probably a lot easier to bend several layers of a lighter cloth than to bend a single layer of a cloth of equivalent weight. Any pros and cons to doing it this way?

Posted: Mon Mar 27, 2006 1:11 am
by CC TX
lncc63 wrote:Sorry guys but I have to ask: Isn't it bad to thin the epoxy with acetone? Does the acetone end up evaporating or does it get integrated into the epoxy?
Yes, according to SystemThree, it is bad to thin epoxy for fiberglassing or gluing. However; the epoxy can be thinned for other purposes such as a base for varnish or painting. The thinner will make it easier to brush on. Some epoxy manufacturers recommend laquer thinner to thin with and not acetone.

Posted: Mon Mar 27, 2006 10:17 am
by Kayak Jack
My first three stitch & glue boats were from kits. They furnished a looser weave cloth, frankly I can't remember what weight or weave.

What I DO remember is that (1) it conformed nicely wherever I tried to put it, and (2) my boats were exceedingly strong.

From my personal point of view, I see no need for a lightweight, tight weave cloth. I definitely do see need for a looser weave cloth. Just my point of view.

Posted: Mon Mar 27, 2006 10:31 am
by Oldsparkey
If memory serves me correctly, six ounce glass came with the kits.