Best way to repair this fiberglass damage?

[FishFinder]

There is an approx. 3" gouge in the bow of my boat (picture attached), it's about 1/4" deep. I tapped the hull around this gouge, everything seems solid. Yard wants $450 to fix, I'd like to do it myself, but haven't done this before. How would you fix this gouge? Any product recommendations (have already been told West Systems epoxy filler is good??) Maybe you know of a good tutorial on the web to help me? Sorry this is the best picture I have now.

Thanks.

[hotdogs]

West makes a really nice paper guide on dong fiberglass repair that you can get on their website for a little more than the cost of postage. It's not online, but it's nevertheless a nice reference. I got mine a few months ago and was able to read it fairly quickly and learned a lot. You might give that a try, see if you feel comfortable, and go from there.

[CalebD]

Wow. SailingDawg must be on his boat or something or he would have given his ABYC standard answer by now.
I think his suggestion would be something like this:
- grind and bevel the surface to a 12:1 surface incline (for a gouge 1/4" deep that would be a 3" bevel at 12:1)
- fill your beveled repair area with West System epoxy (thickened with some colloidal silica) AND glass mat. Build up layers of cloth until you reach the level of the surface,
- fair the repair (by sanding) after taping it off
- apply gel-coat or paint over the repair

The West System how-to manual IS online at their website: Fiberglass Boat Repair and Restoration

It should only cost you about $100 in materials but it will take quite a bit of time and learning.

[scottyt]

the west repairs are online, and lots of others, just google fiberglass hull repair.

that damage is about 4 to 8 hours of repair with 24 hours of curing time spread out between 1 hour repair times. honestly 450 is not bag unless they are just going to fill it. if they are going to grind it out and build it back up, then it miight be worth having them do it.

i would not do just a fill repair on it, i would at least grind it out half the depth and taper the repair out of 1.5 to 2 inches. this would also let you see if it did more than you think as you grind it out.

all in all the material would be less than 50 weither you grind it all out or fill it

[sailingdog]

Do you know how thick the fiberglass there is??? If it is fairly thick and the gouge doesn't go more than a small bit of the way through it, you might be able to get away with filling the gouge with thickened epoxy...like MarineTex.

However, I would personally recommend:

• washing the area with a good detergent, like TSP,
• then de-waxing/de-greasing the hull with something like Interlux Fiberglass Prep Wash 202, and
• then grinding/sanding the area around the gouge to a 12:1 bevel... and
• then re-building the area with several layers of fiberglass cloth and epoxy resin.

Once this area has been built back up, you can fair it with thickened epoxy and sand it to match the original contours and then gelcoat it.

LOL... just saw CalebD's post... Yeah, he's right.. I was checking e-mail, not Sailnet.

BTW, cloth is far better than mat for this kind of repair, IMHO, since cloth is generally stronger than CSM is.

[FishFinder]

Originally Posted by scottyt

honestly 450 is not bag unless they are just going to fill it. if they are going to grind it out and build it back up, then it miight be worth having them do it.

The yard was going to: "Grind back to clean glass. Fill with West System Epoxy. Fair. Colormatch gelcoat." 4 hours quoted. So looks to me like they were just going to fill?

The fiberglass is pretty thick up there but I don't know exactly how thick unfortunately.

The Marine-tex option, this sounds easier and if I understand how this works, I wouldn't have to grind out as far. Is there some reason marine-tex would be less desirable here versus doing the big grind out/build up?

[sailingdog]

It would effectively just be filling the damaged area, but not really restoring the strength to the area the way grinding and laminating new fiberglass would. The strength of fiberglass is primarily in the glass fibers.

Originally Posted by FishFinder

The Marine-tex option, this sounds easier and if I understand how this works, I wouldn't have to grind out as far. Is there some reason marine-tex would be less desirable here versus doing the big grind out/build up?

[seabreeze_97]

Marine Tex is a heavy duty structural epoxy. The white stuff has a compressive strength of 8,700 psi and an adhesion shear strength of 2,300 psi. How much stronger do you need it to be?

[FishFinder]

Thanks guys, great info I learned a lot today. I think I'm going to go with the filling option this time, probably take Dog's suggestion for Marine-Tex. My slip neighbor (former fiberglass boatbuilder) looked at the damage back in October and he said this was more of a cosmetic issue than structural, so I'm not worried about strength too much here. Although it sounds like Marine-Tex will add some strength to the repair ...

I also want to minimize the amount of grinding because my amateur attempts to match gelcoat probably won't hide the repair very well

[sailingfool]

I would not use MarineTex as I would would worry that differences in expansion rates and shrinkage would result in cracks developing. Expoxy filler would be better, glass would be best.

the real issue with this repair is whether you will mind a bright white spot on the bow of your boat...what you would really pay the yard $450 for is their expertise in matching the gelcoat so the repair is hard to see, say from 10 feet away. Do it your self and you are likely to have a bright white spot on your bow for the rest of your ownership. If you are Ok with that, go for it, this would seem to be a cosmetic repair.