Is West Marine 105/205 waterproof or resistant?

[CaneCutter79]

I've got some 105/205 epoxy resin mix that I'm applying to a crack in my hull. Since it's on the very bottom of the hull, I'm wondering if I need to go to the expense of applying gelcoat when only fish will see it? :lol:

The container says "great water resistance". It does not imply waterproof however.........most epoxy products like JB Weld, Bondo, Evercoat, etc. clearly say "waterproof".

The repair is a really small area and not a hole repair, only infilling a crack with 105/205 mix with filler and applying extra resin over the top of the filler as added thickness.

 

[ondarvr]

Re: Is West Marine 105/205 waterproof or resistant?

Nothing is really waterproof, there are only varying degrees of water resistance, but yes this epoxy would be considered waterproof.

As for the crack in the hull, just filling it may not be the way to fix it, and putting more epoxy over the surface won't do much. If it was an actual crack or similar damage any repair should include glass for it to last very long.

 

[CaneCutter79]

Re: Is West Marine 105/205 waterproof or resistant?

Yes I applied a generous 3 layers of fine woven glass from West Marine as well as the "peanut butter" filler mix as directed by West Mariner's instructions.

This stuff is awesome! But you have to keep the pot stirred while applying or it will start smoking and harden on you before you can finish using it all. Learned that the hard way.


I have enough glass and resin mix with filler mix that I'll eat my own shorts if it cracks again. Lol!

 

[CaneCutter79]

Re: Is West Marine 105/205 waterproof or resistant?

So as far as I can tell, gel coat is an epoxy resin but includes color/flake mixed in and it's exact chemical formual mix is a bit thinner than resin and slightly different. It can be thinned to allow spraying or applied with a putty knife and then sanded.

Either way, I think the 105/205 mix will be waterproof as long as the boat is not sitting in a dock, in the water 24/7 and 365. I average a 4-6hr time on the water on weekends and then it's put on the trailer to dry till the next weekend.

I just wanted to make sure the water exposure would not deteriorate the epoxy rapidly and that gel coat was not a "sealer" per say. Gel coat from what I have found is a thinner and slower curring epoxy resin that has color either premixed (white) or allows color to be mixed in.


I've learned a lot about fiberglass repair in this process and found it surprisingly easier than I had expected. It's a lot of fun! Stressfull....but can be fun. (and expensive)

SO Glad this particular forum has so much info readily available about basic fiberglass repair!

 

[glenn property of pam]

Re: Is West Marine 105/205 waterproof or resistant?

i have a small tin of gel coat i bought a while back i think the gel, color agent and mek cost about $25 total and i have used it on many places to cover up my nicks, scratches, extra holes. before that i use to use the epoxy stick which goes on well but after a few months goes from a white to a yellow and starts to crumble. Im not sure how long the gel will be good for in the can but ive fixed 20 plus nicks in the gelcoat and once wet sanded it real hard to see it. I believe they even do smaller kits. One experiment i did on a deep scratch (not structual) was to mix cabasol with gel coat (gel coat is real runny and a pain to apply upside down) then after it was set and sanded i coated with gel coat and its been there over a year and still looks the same as the day it was done (nearly invisable).

 

[CaneCutter79]

Re: Is West Marine 105/205 waterproof or resistant?

Yep, I used "cabasol" by West Marine to make my "peanut butter" mix.

I'm going to keep a close eye on the epoxy for the next few trips out. Just to ensure it's holding correctly, holds up on finish, etc. If it shows any signs of "yellowing" or drying, I'll sand it down to good stuff, re-apply and then gel coat over.

Yeah, a small container of gel coat is cheap enough to use but when the wife is complaining about every little dime I sink into an already "repair-prone" older boat with a newly rebuilt motor, I try to save where I can.

I'll may gel coat it anyway in a few weeks after it's fully curred. Just to be extra safe. Plus I can fill in a few scratches myself.

 

[ondarvr]

Re: Is West Marine 105/205 waterproof or resistant?

Epoxy and gel coat are two totally different products with very different chemistry. You shouldn't use gel coat over epoxy, the bond isn't all that good.

Epoxy is far more water resistant than gel coat, so water isn't going to have much of an effect on it.

 

[glenn property of pam]

Re: Is West Marine 105/205 waterproof or resistant?

Epoxy and gel coat are two totally different products with very different chemistry. You shouldn't use gel coat over epoxy, the bond isn't all that good.

Epoxy is far more water resistant than gel coat, so water isn't going to have much of an effect on it.

thats a good point as the repair was made with epoxy that sticks to poly but doesnt work the other way around. so what is the epoxy equivalent of gel coat or is it just colored epoxy?

 

[jbcurt00]

Re: Is West Marine 105/205 waterproof or resistant?

I know it's the bottom of the hull, but do you need to protect it from UV? I suspect that's part of the reason the epoxy stick changes color, crumbles & fails, its not UV stable......