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questions about hull wear (bottom)...
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Author:  cyrano138 [ Thu Nov 23, 2006 3:26 pm ]
Post subject:  questions about hull wear (bottom)...
The bottom of my hulls (1987 hobie16) have worn through to the fiberglass mat--i can see the resin-coated mat, but as far as i could tell, it hasn't worn into the actual fibers of the mat. I spent an hour reading through all the old posts on this forum and in the repair forum and have come away with just about as much conflicting advice as possible. Some people say don't worry about it, some say fix it, some say polyester resin, some say epoxy, some say paint, some say gel-coat...it just goes on like that.

So if you don't mind going over this again, here are my questions:

--do i need to fix it?

--what is the white outer-layer on the hulls now? is it polyester or epoxy, or is it even fiberglass? i'm asking because i need to know if i can lay resin over top of it.

--what resin was used when the boat was originally built? i mean the stuff in the mat that is showing through (the fiberglass part of the fiberglass-foam sandwich), polyester or epoxy?

--as i've said before on here, i repair surfboards and work extensively with polyester resin, but i'm willing to use epoxy. So which one should i use?

--is it okay to turn the boat over and just let it rest on the tramp frame?

--how deep does the wear have to be to neccessitate cloth (instead of just using resin)?

--do i really have to put anything over the resin once the fiberglass work is done? i really don't care how the boat looks, i just want to make sure it's solid.

thanks for all your help and responses!
Author:  Tobbera [ Fri Nov 24, 2006 6:04 am ]
Post subject: 
AFAIK the boat is built of polyster. The white coat is gelcoat. Thats basicly polyster resin with colour. Epoxy will bond good to both polyster and epoxy. Polyster just bonds to polyester. I really dont know wich is prefeered. If you are used to polyster, I think I would go for that.
Author:  John Eaton [ Fri Nov 24, 2006 7:33 am ]
Post subject: 
Quote:
--do i need to fix it?


Fibers aren't showing? No

Quote:
--what is the white outer-layer on the hulls now? is it polyester or epoxy, or is it even fiberglass? i'm asking because i need to know if i can lay resin over top of it.


It's called gel-coat. I 99% sure (at least the original gel-coat) is polyester resin based.

Quote:
--what resin was used when the boat was originally built? i mean the stuff in the mat that is showing through (the fiberglass part of the fiberglass-foam sandwich), polyester or epoxy?


As Tobbera stated, polyester

Quote:
--as i've said before on here, i repair surfboards and work extensively with polyester resin, but i'm willing to use epoxy. So which one should i use?


Gel coat will go better over polyester than over epoxy, and as you probably know you can pigment the polyester. I'd use epoxy. I THINK it will last longer than polyester. The small West Systems packs are about $25.

Quote:
--is it okay to turn the boat over and just let it rest on the tramp frame?


Yes, put some blocks at the corners, front and rear, so the mast base and main traveller car don't get bunged up.

Quote:
--how deep does the wear have to be to neccessitate cloth (instead of just using resin)?


IMO, if the cloth fibers were worn or exposed.

Quote:
--do i really have to put anything over the resin once the fiberglass work is done? i really don't care how the boat looks, i just want to make sure it's solid.


Ahh!!! No, you don't have to cover it. And, if you don't care how the boat looks just go sailing. If it's not down to the fiber (and even if it was) the boat is still structurally solid. If there are some deep gouges or scratches and you want to fair it up, go for it.

If your not going to restore to original finish polyester OR epoxy. If you are, polyester then gelcoat.
Author:  Sail Revolution [ Sun Nov 26, 2006 3:09 am ]
Post subject:  polyester
Search my other posts re hull repair/fiberglass/epoxy. You should always use what the boat was built of (Polyester) for general repairs. And for bonding, use epoxy. That's the short of it.
Gel will oftentimes not cure over epoxy!!! It turns to a goooooey mess. It happens when there are free amines in the surface of the epoxy, which is quite common. Moist environment, off ratio mixing, etc. (google "amine blush" I'm sure you'll find something)
I'm not sure why people like to use Epoxy for hull laminate repairs. Could someone explain it to me? Epoxy is at least double the price of polyester, and you would never notice the structural benefits for the repairs that we are doing--unless your bonding. Is it the nice pump?
It's nice to keep the substrate consistant, so that there are no surprises down the line if you were to do another repair.
The best way to fix your boat is to go out to your local boat store or fiberglass shop and pick up some polyester resin, a little cloth (just in case), some gelcoat (pigment?), catalyst, and acetone. It will probably cost $25. To cure the gel pick up a product called PVA (Another $4). It basically turns into a plastic film over the gelcoat, which occludes O2 so the gel can dry. Oh yea, get some sand paper and rubber gloves too. Now you're up to $35. Look up fiberglass repair, I'm sure there are some good websites out there. Basically, fill the holes/damage with cloth and resin. Fair. Layer with gelcoat. Fair. Buff. Sail. And, with all that stuff you bought, you have an emergency repair kit ready to go to the lake.
Hope this helps.
Author:  cyrano138 [ Sun Nov 26, 2006 7:43 am ]
Post subject: 
thanks for all the info, everyone. fortunately, i'm familiar with fiberglass repair so i don't need to look anything else up. just one last question, though, what weight cloth should i use? i have a lot of 10 oz. lying around because that's what i use for my surfboard work, but i have no idea if i shouldn't use something heavier for my hulls?

at any rate, i think i'm going to take the boat out a few times before i mess around with it. i bought the damned thing three weeks ago and haven't been able to get out on the water yet...mainly it's been a problem of transportation, so i'm going to wal-mart today to order a hitch for my 4-cylinder honda civic and hope for the best.
Author:  Sail Revolution [ Sun Nov 26, 2006 1:02 pm ]
Post subject: 
10 OZ will work fine. And since you know the drill with surfboard repair, it should be easy for you. The gelcoat is a bit tricky, it won't harden without taking away o2, but that's it. Gelcoat is very forgiving once you get it down. Which coast do you surf on?
Author:  cyrano138 [ Sun Nov 26, 2006 1:32 pm ]
Post subject: 
is it true that the gel coat is just regular polyester resin with pigment in it? the last time i re-glassed my board, i used pigment and didn't have any trouble curing it, and i didn't do anything special to take away the o2.

i surf on both coasts, usually in the winter i stick to the gulf coast since we get pretty decent waves here with the cold fronts, and in the summer i surf wherever the swells are. here's a picture of me on florence this summer, if memory serves. this was taken south of melbourne. the board i'm surfing here is the one i restored and my favorite rider.

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