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Chipped Coaming.

Posted: Sat Dec 22, 2018 1:38 am
by TRH446
My 2003 Big Kahuna has about 3 inches chipped off outer back edge. As much as half an inch broken off. I want to build it up with fiberglass. Should I use Epoxy Resin of Polyester Resin?

Has anyone done this?

Re: Chipped Coaming.

Posted: Sat Dec 29, 2018 5:55 pm
by yuen
I worked with epoxy and fiberglass ned on coaming of older K1 from 98 and it worked. Work outside because of the smells. Good luck!

Re: Chipped Coaming.

Posted: Sat Dec 29, 2018 7:18 pm
by TRH446
That's epoxy resin (2 parts mixed 1 to 1), right? Not the polyester resin (comes in one large container & you add a few drops of "Hardener" and mix) right?

Thinking about running fiberglass cloth all the way around as reinforcement. Is that a good idea?

2003 vintage. Coaming seems kinda brittle. Adding a lamination of glass with cloth would strengthen, but also make thicker.

Waiting for warmer weather. Cures quicker.

Re: Chipped Coaming.

Posted: Sun Dec 30, 2018 7:41 pm
by yuen
I had the epoxy resin with hardener here in Germany.

https://www.ebay.de/itm/46-39-Kg-R-G-28 ... 2366781108


Quiet difficult to measure, use some cheap injection thing without needle from the farmacy.

Used one which started to harden at 30 or 40 minutes. Thats possible to work with.

I put glass around the coaming from the inside and outside, one layer. And under the "lip". Adds weight but also stability. Those coaming are no longer made, so better protect them. After that you can polish it with sand paper and paint it with some black water resistant colour.

Good luck!

Re: Chipped Coaming.

Posted: Mon Dec 31, 2018 12:05 am
by TRH446
Thanks for the info. I'll be working outside, so I need warmer temperatures for quicker curing. I've used polyester resin with & without cloth on old planked wooden decks & on plywood hulls. Polyester is much less expensive. Not as strong.

Feathercraft site says: "large fibreglass coaming ... is no longer made. If a coaming has broken, best to do a repair with an epoxy or fibreglass."

And epoxy definitely affords better adhesion. Though more expensive. And can't finish epoxy with gelcoat.

I think you can actually put color/dye directly in the resin.

Looking at using something like this:

https://www.amazon.com/dp/B00HR8517A/re ... 19e6f8bfdd

And I think your method of sandwiching the original Coaming with cloth & resin is the way to go.

Finished Coaming would be stronger than the original.

Re: Chipped Coaming.

Posted: Sat Feb 02, 2019 5:30 pm
by george
I used to have a boat constructed of fiberglass over plywood. I had to make repairs from time to time.. Epoxy was by far the better choice. Easier to work, much stronger and less brittle.

Epoxy can be messy to work with and once cured it is pretty tough so it requires a lot of strong sanding to smooth out.

A trick for making smooth surfaces is to use micro balloons. Add them to an epoxy mix base and it smooths out easily and can be applied with a putty knife. Once dry, it sands easily to a smooth and level surface.