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Fiberglass Layup

Posted by ozarkdrifter 
Re: Fiberglass Layup
February 19, 2020 03:43PM
"Kevlar is expensive too. It doesn't break but when you sledge hammer smack a rock"

I thought that too, then I took 2 boats on a trip with a friend rowing one of them. Class III easy stuff. Some how he managed to bash every rock on the river? He cracked the bottom in 3 places. 3/4 inch Plascore with heavy 16 ounce biaxial Kevlar and 2 layers of 10 Oz plain weaver. I still can't figure it out.

If it would have been 3/8 plywood with light glass, he might have sunk the thing. I have floated that section 30 times and never put a dent in the boat.
Re: Fiberglass Layup
February 21, 2020 02:03PM
I live in Easton PA and once Labor Day is gone I have the river to myself in this section. The west branch of the Delaware is becoming difficult to find launching access. It seems that the Rednecks you mention have worn out their welcome with land owners along the river.
Re: Fiberglass Layup
February 22, 2020 03:50PM
Easton, that brought back something I have not thought of in over 50 years. One time my father took me up to Easton where we launched and motored up the river a few miles. Camped for 2 days, fishing etc, then ran back down river to the truck. We had an 18 foot Old Town canvas canoe with a 2 X 6 mounted on the back for an outrigger mount for a 3 HP Johnson outboard. At one point the water was fast enough we came to a crawl.

A high school friend's family had a river front second home a few miles up river from French Town on the Jersey side. We had lots of fun there skiing, the water was always like glass since their place was up river from a dam.

Most of the time our Deleware outings were down at Upper Black Eddy.

The river out here stay busy till Late Oct.
Re: Fiberglass Layup
February 23, 2020 12:57PM
Thought of something this moroning. What Larry said is correct--smooth it up a bit and add another layer of fabric over top.

But don't add that extra glass now. Wait until it's on the boat, and already bent to shape. If you glass it again now you can still work with it. But it will be harder to bend--because of that extra glass.
Re: Fiberglass Layup
February 24, 2020 01:05PM
I learned to water ski a couple of pools up from Frenchtown, Lumberville, PA. Canoeing the upper Delaware is tranquil. Until recently I used a 17' Oldtown discovery (tripper). I tied a Kayak but once in a Buffalo I was sold. If I build another I'll get rid of most of the Rocker. Yesterday I saw an aluminum 17' Drift boat come through Easton. They must be after Walleye or Muskee. Then a tiller driven jet zipped through.

I agree not to Glass further until the boat is all formed. I had thought that it was already but if not wait until it is.
Re: Fiberglass Layup
February 24, 2020 04:19PM
I only patched the cut out bubbles with a "cut to fit" patch. Haven't done the second full layer. Already have the bottom attached, no issues bending to shape. Will drop in the second layer for the interior when the boat gets flipped over. Currently been busy and no progress in a few weeks. Hope to remedy in first half of March. Hunting season over, fishing not good yet, rains every day and cold. I think March may be a month designed for building....
Re: Fiberglass Layup
April 21, 2021 06:16PM
Working on a boat for the first time. I am working with mohogany on the bottom due to current plywood prices. Curious what everyone’s process is when putting multiple layers of fiberglass on the bottom panel. I was planning on doing a coat of epoxy on the plywood and letting that soak in. Then putting my first layer of glass down when the epoxy gets tacky. After this all dries should I put another coat of epoxy on top of my first layer of fiberglass before I put my next layer of fiberglass on? Or should I just put the fiberglass on dry and work epoxy on from the top? Just curious what your thoughts are. Appreciate any input.
Re: Fiberglass Layup
April 21, 2021 06:31PM
RE> "After this all dries should I put another coat of epoxy on top of my first layer of fiberglass before I put my next layer of fiberglass on? Or should I just put the fiberglass on dry and work epoxy on from the top? Just curious what your thoughts are. Appreciate any input."

There is an element of style and preference here. Many people do just what you say in the second part (put glass down dry and work the resin into it). I prefer to always wet out first and then stretch glass on top of the wet resin. It helps to have 4 hands to work that way but it isn't required.

I also prefer to do any layup start to finish all in one go. But it isn't required. You can quit early. Perhaps because you are running out of time. If so it's important to wash the hardened layer with acetone and a rag. Sand lightly and then go again. Do you wet out first or lay the glass down dry? That is a preference you can only come to by trying both.

I always wet out first. Then put down glass. Then finish wetting out, usually by pouring resin into a puddle in the middle and stroking it out to the edges with a 10" drywall trowel.

Some fabrics are easy to wet out. Some bi-axial (not all but some) are harder to wet out. When that's happening you'll want to wet out first. Pushing resin into a dry layer that does not easily wet is not much fun.
Re: Fiberglass Layup
August 29, 2021 09:36PM
I like the idea of using a biaxial layer for added strength but I thought the angle of the weave, say 45x45, provides the additional strength. If this is correct wouldn't it be okay to work with a lower weight biaxial cloth?

Nothing assumed here. I have never worked with biaxial and I do not know how the floors/bottoms of these drift boat hulls are usually laid up. I'm asking questions to learn.
Re: Fiberglass Layup
August 29, 2021 09:42PM
The RAKA website shows Dynel and Xynole in the fiberglass section. The one comment I felt compelled to add to this discussion is that RAKA states/claims Xynole should not be used for strength in Stitch and Glue applications for strength. See this url for the comment:


Can anyone comment on use of the this or Dynel?
Re: Fiberglass Layup
August 29, 2021 10:47PM
So Xynole is polester. I've not used it so I cannot say from experience but what RAKA says does not make sense to me. They say it has good abrasion and impact resistance but because it stretches it does not add stiffness, so do not use for stitch and glue.

However, stitch and glue over a plywood core gets its stiffness from the plywood. The glass layer provides abrasion resistance, and prevents moisture from penetrating to the plywood core.

Back in the 1980s there was a one man show called TechOn that sold a two part epoxy laminating resin and various fabrics. That guy was particularly a fan of polypropelene fabric. It had a tendency to soak up more resin than glass but it was amazing. You could bend it over flat and run your thumb over the crease and it would not break or crack. His particular brand of epoxy (he's long gone now) was particulary flexible. Polypropelene fabric combined with his resin made an amazingly durable layup that worked well over plywood.

The following link shows materials names matched to trade names. Stitch and glue boats are the best, most long-term durable boats for home boat builders.

I built the first stitch and glue drift boats in the early 1980s. That was so long ago the term stitch and glue didn't even exist. I called them "ribless boats."
Stitch and glue and welded aluminum make the best DIY boats.

I've built so many wood/glass composites I'm bored with it and am now doing something new, just to stay interested. I'm scewing and bolting 3/8" marine plywood together over foam gaskets and thick thick thick beads of marine grade slow-setting caulk. I like this idea. If something breaks I can take it off and replace it. But it is an experiment at this point.

For those who ARE NOT yet bored with stitch and glue it is the way to go--at least if you are not an aluminum welder. I'm interested in aluminum too now. You can think of it as funny looking plywood that you weld at the edges instead of glue, and get good long-term durable DIY results. Close to a half a dozen of my customers have built my designs as aluminum now. I wish I'd learned more about a long time ago.

In the stitch and glue context you can spend a lot of time trying to second guess every step and every material choice. If you use a regular glass fabric from some place like RAKA you'll do jut fine. Fancier layups are undoubtedly better. But how much better?

Here's a useful link matching fabric types to trade names and manufacturers.
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