Fiberglass Gurus I have a question

[flattie]

I have done lots some glass work last year I did a total re- do of the floor and bulkheads. So Im not afraid of this little project. Just looking for another set of eyes to look at it
Im about to glass up the gas tank holes in my boat. But before I start I need to mask off the cockpit of the boat to keep most of the grinding dust out. I have cut out some light weight foam core and glued it in from the back side as you can see then I will have to take the grinder and feather out the glass and then I can start my glass work. Would anyone do this diffrent?
http://www.***boat.com/image_center/data/500/DSC04809.JPG
http://www.***boat.com/image_center/data/500/medium/DSC04807.JPG Also how far would you feather it out? Also Resin Epoxy ect?

[McIntyrelocal]

lay some plastic down on the inside and glass a srtip is on the bottom side of the holes.

[Sangster]

Nothing wrong with doing it that way... Although I would also remove the foam core when done and place a layer or two to the underside of the patched area...

[McIntyrelocal]

and i would grind around the line of the exhisting cap down for a couple of layers of mat so when you do your finish body work the holes wont show up when the paint shrinks back.

[flattie]

What about resin or epoxy?

[McIntyrelocal]

What about resin or epoxy?
what about it?

[flattie]

what would you use?

[McIntyrelocal]

id glass it from the bottom let that set up then go to the top feather the hole out a little layup however many layers of glass it takes to fill all the way up not all at ounce and grind smooth and do your finish work with bondo.then primer it block it and paint it. resins and epoxies work good to fiil the holes but they dont bond well to exhisting glass especially really thin areas they would probably crack out from my experiences and from what ive been told is thats when your doing fiberglass when your done you want as little resin left as possible the strength is in the glass not the resin its always worked great with everything ive done capped a few boats and done other major glass work. hope that helps

[Lefty]

Resin or Epoxy? My thinking on this would be to use what the boat was made out of. You want you repair to have the same properties as the rest of the boat. That way they give and stress at the same rate. I know this is not a regular place for cracks to occur, but that would be my reasoning. I also would build it from the bottom out. I would back the inside with wax paper after putting my inside layers on. Let that set up nice and hard and then go do the outside.

[jimsplace]

If the light weight foam backing is what I think it is,
before you place any resin on it, test it. (resin on excess piece of foam)
Polyester resin and I assume vynelester resin will dissolve it. Epoxy resin can be used directly on the light weight foam OK. A plastic sheet or mylar placed on top of the foam may work. But try it.

[VD CRUISER]

I don't know if any body actually answered your question about what kind of resin to use or not. The boat is most likely made using polyester resin and thats what I would use for the repair.

[jimsplace]

I would suggest contacting "West Systems". They are a mfg. of epoxies and have some really good products. Also, if you go to there website, they have some really helpful information on doing repairs and the use of glass work.
They also have some very helpful instruction manuals and DVD's.

[Sangster]

Another thing that might help you out would be doing a search/google on Fiberglass video's.....There are some West Marine Videos out there along with others that are at least something to look at..... Good luck...:)

[BrendellaJet]

You dont need the overpriced west systems crap for this. Polyester resin, glass from below first, and then proceed as planned. Feather it out though to get a strong repair. Will probably take 8-10 ounces of glass when all is said & done.

[flattie]

Well I started tonight by glassing in with some mat from the bottom. I will start on the top as soon as this drys and I can get to the top to do some feathering out http://www.***boat.com/image_center/data/500/DSC04813.JPG

[McIntyrelocal]

looks good man thats the way i would do it. after each layer before yo put the next on scuff the preivious so yo uhave good adhesion. nice boat by the way the inside looks beautiful.

[VDRIVERACING]

I'm liking the green tape

[Kurtis500]

I'm not sure if someone mentioned this already, but you need to heavily reinforce the area underneath. If you do not, the circular shape of the hole will bleed through the surface paint in the form of a crack or change in the smooth texture of the surface. It may cause a ridge or etc. Over time, the new resin and glass will slowly continue to shrink whereas the old stuff already has. If someone were to step down with a foot or hand on that little circular area it may create that little depression were the hole used to be..
Make sense?

[Rattle Can Lou]

Thats why it's real important to feather it out about 8" on either side of the hole and I would go down about 4 layers of mat around the hole and work it up from there.

[flattie]

Wow that far? I was going to go out about 5 inches to the left and right of it and as far as I could on the top to bottom so I only had to re shoot the blue and not the white also

[Rattle Can Lou]

That'll work. I had to redo mine on the Rayson and wasnt dealing with paint. I'm sorry, I gotta little carried away. I hate seeing anything transfer up through the finish. I think you'll be fine.

[McIntyrelocal]

as long as you let the fiberglass setup real good once you do the finish body work and paint it the fiber glass doesnt shirnk the paint shrinks and depending on what filler you use it could expand and contract with heat thats why i would just use bondo if you do the paint will shrink but if you put enough clear on it you should just be able to color sand it out but it takes a while for it to shrink.

[flattie]

I think after Im done glassing and making it flat I will put epoxy primer on it and leave it sit till spring in the heated garage.

[McIntyrelocal]

i dont think thats necisary (spellin) but i would paint it and let that sit because the paint will shrink not the glass or the primer but poly primer is a real good durable primer and works with all most if not all paint.

[2manymustangs]

SOme very trusted fiberglass guru's always told me to use poly resin and not epoxy so that the repair moves, flexs and acts the same (hot and cold) as the original material. The more you feather it out the better/stronger the repair will be and ALWAYS clean off the new resin with acetone (with rubber gloves of course) to remove the waxes prior to adding more layers.