Fiberglass is too expensive for my IMP, can I use epoxy and varnish to show the wood?

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Cconrad
Posts: 4
Joined: Sun Dec 27, 2020 7:02 pm

Fiberglass is too expensive for my IMP, can I use epoxy and varnish to show the wood?

Post by Cconrad »

Building my first boat, trying to control the costs and would like to show off the woodwork. Fiberglass is so expensive, $400 just for a small row boat seems very expensive to me. Can I seal it with clear epoxy and then varnish? Will that provide the protection needed along with the look?

Which Epoxy Sealer is the correct one for this type of sealing and varnish?

JimmY
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Joined: Sat Jul 30, 2016 11:08 am
Location: Brighton, MI

Re: Fiberglass is too expensive for my IMP, can I use epoxy and varnish to show the wood?

Post by JimmY »

The fiberglass is mostly for abrasion resistance, unless this design call for glass reinforcing at the seams. The Glen L site shows the kits for the IMP at about $300. Out of that price, the epoxy is about $200. Either way, you will need to encapsulate the entire boat with epoxy, so the cost of the cloth is relatively small compared to the epoxy.

If you use a 4 oz. weight cloth, or even a little heavier, the glass will disappear in the epoxy. I recommend the System 3 Silver Tip epoxy for glassing and encapsulating. It is a no blush formula, so you can apply the next coat within 24 hours without sanding. It is a little more expensive though.

Any epoxy that will be exposed to the sun, or water, will need to be protected with paint or varnish. Some varnishes have issues curing over epoxy, so do your research. If you go with the System 3 epoxy, they have a line of WR-LPU that is easy to apply and will hold up well on a boat that is not kept in the water 24/7 (it is a top coat, not a bottom coat). If you plan to keep you boat in the water, you will need a marine bottom coat paint.

When you get into anything rated for "marine" use, the price goes up.
-Jim
Nothing says poor craftsmanship like wrinkles in your duct tape!

Cconrad
Posts: 4
Joined: Sun Dec 27, 2020 7:02 pm

Re: Fiberglass is too expensive for my IMP, can I use epoxy and varnish to show the wood?

Post by Cconrad »

Jim, thank you. It is all starting to make sense now, bit by bit.
Last edited by Cconrad on Mon Dec 28, 2020 4:44 pm, edited 1 time in total.

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Ibrew2be
Posts: 176
Joined: Sat Aug 03, 2013 4:52 pm
Location: Cincinnati, OH

Re: Fiberglass is too expensive for my IMP, can I use epoxy and varnish to show the wood?

Post by Ibrew2be »

What Jim says is right, on the IMP, the fiber glass is for abrasion resistance. The design does not call for reinforcing the seams with glass. You will want to encapsulate the boat with epoxy to seal the wood.

When I built my IMP, I glassed the bottom and about 2 inches up the sides, but no further. That's an approach you could use to minimize the amount of glass you need to buy while still protecting the most vulnerable part of the hull. Similarly, I painted the bottom and that same 2 inches up the side. The rest of the boat is finished bright (i.e. epoxy and varnish only). I used Glen-L Poxy-Shield for my epoxy, and it has the benefit of being somewhat less costly than System Three Silver Tip (which is a great product, BTW). Poxy-Shield is prone to amine blush, but that was easy to deal with. Once the epoxy had cured, it simply required wiping the surface down with a detergent solution to get rid of the blush. The paint I used was System Three WR-LPU that Jim mentions. I liked WR-LPU and plan to use it again.

I didn't have any difficulty varnishing over the epoxy, but other builders have had problems with the varnish not hardening. I think the reason I didn't have similar headaches is because it turned out to be a long time (a month or more) between the time I applied the epoxy and when I did the varnishing.

Barry
Barry Shantz

Imp built and launched.

Slowly building Ken Bassett's Rascal

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