Fiberglas patch

Westie · Posted: Sun Apr 10, 2016 8:48 pm Post subject: Fiberglas patch

Hi there,
I pulled out my tomcat and banged my hull against the trailer causing a 1/4" deep scrap. I'm looking for advice on how best to repair. I have ablative bottom paint. Thanks in advance.

thataway · Posted: Sun Apr 10, 2016 10:21 pm Post subject:

If it is all beneath the waterline (where the bottom paint is), Take a small grinder and clean up the margins, and bottom of the gouge. (great place for the Dremel Tool). Get some MarineTex epoxy. I keep a small container of the gray and white. Fill in this area slightly proud of the surface. Let it harden, and take a small detail sander, or by hand, and sand it smooth, put some of the bottom paint (may be a good time to do this all around the water line--since that is where it tends to degrade first)

If it is above the water line, then a different repair. You want to fill that area, with mill fibers and polyester resin. Fair it smooth, and then apply gel coat, to match.
I like to have a 20 mil layer of gel coat. Certainly you can build it up with several coats, or apply that much to start with. Choice of application with a Preval sprayer or brush on. For a small amount, I tend to use a brush or plastic spatula. You want the gel coat to be "Fresh". Spectrum color seems to still make a small repair kit for the C Dory. If not, white gel coat, tinted with a very small amount of yellow and brown to match. Again the Dremel tool to clean out the gouge.

For 1/4" deep and wide gouge, no cloth is necessary. If you prefer, and have some cloth, you can lay in some random fibers along the axis of the gouge.

Marco Flamingo · Posted: Sun Apr 10, 2016 10:38 pm Post subject:

Polyester fillers like MarineTex and Bondo go through a hardening phase that is called "cheese." For a period of about 5 minutes (depending on temp and amount of hardener) they have a cheddar cheese-like consistency. That's when to use a "cheese grater" type of wood rasp. Easily cleans up an ugly, bumpy mess of filler and with a little finesse you can go directly to hand sanding. Miss that stage and you've made yourself 3 times as much work.

Mark

Westie · Posted: Sun Apr 10, 2016 11:45 pm Post subject:

Thanks! its the very bottom of the keel so it should be pretty easy to repair.

thataway · Posted: Mon Apr 11, 2016 12:16 pm Post subject:

Westie · Posted: Mon Apr 11, 2016 12:54 pm Post subject:

Thanks - since I have a small scrap on the keel, will the Marine Tex Marine Tex Rapid Set by the right product?

http://www.amazon.com/Marine-Tex-Rapid-Set-2-Ounce/dp/B000Y8A06C/ref=sr_1_3?ie=UTF8&qid=1460393503&sr=8-3&keywords=marine+tex+black

There is a putty but I'm thinking that is for larger structural damage repair.

thataway · Posted: Mon Apr 11, 2016 3:10 pm Post subject:

I don't consider Marine Tex for any structural repair. It is a filler. For structural repairs, one needs to use fiberglass materials--usually tape,fibers, or matt. Marine Tex is not often the best item for structural repair.

I have not used the 'rapid set". Reading the reviews, it seems to fine, although there were a couple of people disappointed, where they thought it would be harder like JB weld.

I would give the rapid set a try.