Few fiber glassing questions

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hughhallhh56
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Few fiber glassing questions

Post by hughhallhh56 »

Well got busy last week and stripped the canoe and this weekend epoxied on and shaped the outer stems. Other than a light sanding with some finer sandpaper I am ready to glass the canoe. As I was finishing one of the stems I got to thinking about how to handle the stems when fiber glassing. I watched a youtube video and the person just extended the cloth past the stems a few inches. When the epoxy hardened he trimmed it and put on a 4 inch bow strip. In another case the person folded the cloth over as he finished the stems creating two layers. Not being too experienced in fiber glassing, what is it easy way?

Next question is on whether to put on an epoxy coat before fiber glassing or just lay the cloth and put on the epoxy.

Thanks
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Cruiser
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Re: Few fiber glassing questions

Post by Cruiser »

Hi Hugh,

Everything I have read says not to try to fold over the glass at the stems ... if I remember correctly Ted is quite adamant about that in the book. Adding a 4" piece of tape seems acceptable practice.

As far as precoating with epoxy... that is going to likely generate some discussion. We have builders who swear by both methods .... I won't say which you should use, I personally don't precoat, it seems like extra work and just putting the initial epoxy on with the glass seems to work for me.


Brian
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Jim Dodd
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Re: Few fiber glassing questions

Post by Jim Dodd »

And as Brian promised ! Here is some discussion. :thinking

My thoughts, if you built your hull without staples, you beaded and coved the strips, and have no gaps or knots. I'd forget the seal coat ! You will save weight and resin !

This last Fall I helped a friend glass an outstanding hull ! I've been building for years, and have not done as nice a job stripping as friend Bill did ! There was no need for a seal coat.

I build with staples, a few knots, and occasionally a small gap. I seal coat. I always have, and probably always will !

I really hate to see epoxy weep down a staple hole, and leave a crater when it comes time to sand, it's a real pain to fix.
I don't fill staple holes with putty. My trick is to Roll on a seal coat, wait at least hour.
Mix a small 3 oz cup of resin, and with a small foam brush, paint the staple holes.
This double seal coat on the staple holes, seals them, eliminating weep holes.

What ever route you take, good luck !
End of discussion on my part ! :applause

Jim
Keep your paddle wet and your seat dry!
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Cruiser
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Re: Few fiber glassing questions

Post by Cruiser »

That's a really good point Jim, I build without staples and hadn't thought about a seal coat fulfilling that kind pf purpose. I am going to file that away, I have a friend I usually help with glassing, he builds with staples... so this could be a good tip for him, thanks for sharing that.


Brian
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Patricks Dad
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Re: Few fiber glassing questions

Post by Patricks Dad »

No need to try to wrap the cloth around the stems. Just trim along the edge of the outer stem and sand down smooth. Put on a separate strip (or 2) of cloth that is cut on the bias. Don't try to lay glass cut parallel with the weave (it will not wrap nearly as nicely). Glass cut on the bias (45 degree to the weave) will wrap nicely around the stems.

As for pre-coating. I never have. I think you could make an argument that pre-coating will use less epoxy (put on a very thin coat to seal the wood before putting the glass on will use less epoxy than fully saturating the wood when you glass - giving it as much epoxy as it can possibly absorb to ensure a full saturation of the glass).

But if you pre-coat, you really want to wait just the right amount of time before you put on the glass (so it's no longer tacky but still green enough to take the next coat of epoxy with chemical bond). Again, I don't see a strong argument for pre-coating.

enjoy your build
Randy Pfeifer
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hughhallhh56
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Re: Few fiber glassing questions

Post by hughhallhh56 »

Thanks for the input.

Stapleless construction. Bead and cove. No knots and no cracks (well at least I filled the few I had). So no precoat it will be. I'll trim the cloth at the stems and use a bias wrap later. Hope to do this weekend. Temperature is cool (15C - 59F) but I have a heated shop which is nice so I can set the temp to 70.
Rabbit
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Re: Few fiber glassing questions

Post by Rabbit »

certainly a dry layup is easier. most people here when they talk about pre-coating are talking about a seal coat that is allowed to dry. my epoxy manufacturer is a bit different. they specifically state that their product is most effective with wet on wet application. the first coat contains a timber treatment which both protects the timber and makes the epoxy thinner for better penetration. the glass is laid down on top while the coat is still wet and the wet out coat of untreated epoxy is applied. when you are doing this as a one man operation on a full sized canoe hull, this is a pain in the butt and it's hard not to get any wrinkles, but it is doable. i did a dry layup on the inside hull and i didn't see much difference.
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Jim Dodd
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Re: Few fiber glassing questions

Post by Jim Dodd »

Rabbit
I'm glad you brought up "You're Epoxy Manufacturer" !
I don't think the RAKA products, that I use recommend doing this.

I watched a video of this being done, "North West Canoe", but it depends on the Epoxy brand !

I'm sure I would destroy the weave trying to move the cloth around in the sticky resin, I use.

Jim
Keep your paddle wet and your seat dry!
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Denis
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Re: Few fiber glassing questions

Post by Denis »

No real need to precoat, adds an extra step. Just be sure to have enough time to do the wetout in one stage. If you have a mixer that is a big help and if you have two persons applying you should be able to get it done in a few hours. It is a pain to clean up the leakthrough in the staple holes inside after but it is doable with a sharp paint scraper that has been rounded to take off the sharp edges. Check Canoecraft for more info on that process.

The four inch piece you are planning on adding should be cut on the 45 degree bias then it will wrap around the outer stem neatly. If your outer stem edges are going to remain squared off you may have trouble getting the cloth to lay flat.

Denis
alick burt
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Re: Few fiber glassing questions

Post by alick burt »

I don't usually precoat but I tried it once just to see if there was any benefit.
The conclusion I came to was
1.that I wasted time (I had to let it dry and sand before proceeding with lay up).
2.I used more resin by the time I had finished.
I know it works for some but I can't see the benefits if there are any! I use UK epoxy and I have done both stapled and non stapled builds.
Cheers :wink
Alick.
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