fiberglass question

[wiz]

I have a 18' 91 kenner boat that i have taken the carpet out and sanded. Luckily floor was in great shape. My intentions are to gelcoat whole topside.
The front casting deck i did not have to remove too much glass when sanding to get glue off so i thought i would cover it with some leftover 6oz cloth i've had for a while just to add a little back to it. Seem ok?

The real stumper is the gunnel walls. Took carpet back and there was just some roving showing on the vertical surface. Didn't look like there was mat behind it and sure wasn't mat on top of it. So started sanding it and took away just about all the roving(but not all) to get glue out of the roving's divits. I need to put something back there but i don't really want to use mat/roving/mat cause i think it would add too much weight considering it was only like 18oz roving showing to start with. ?did they use epoxy in early 1990's to build boats? Anybody got any ideas what i might be able to substitute where the roving used to be? Seems like putting heavy roving back there would be over kill, i think. I'd really like to keep the weight down. What about S-glass, kevlar or Carbon?

 

[tashasdaddy]

Re: fiberglass question

cost.

 

[wiz]

Re: fiberglass question

aaaammmm yeah those last two are costly. And yes i want to keep cost down as well as weight and time too. I think that's what you are refering to.

 

[ondarvr]

Re: fiberglass question

It's not epoxy, just regular polyester.
You could use carbon, or one of the other high end fibers, but you probably haven't looked at the cost of using them $$$$$. You don't say how big the area is that you need to repair, but I can't imagine it adding more weight than the carpet you took out and what you already ground off.

As for the cloth, if you didn't remove much, don't put it in, if you do use it, you will need to use epoxy, as cloth does not bond well when using polyester.

If you can post a pic it will help.

 

[wiz]

Re: fiberglass question

For the area it would be the whole wall both sides, about 10-12 ft.

I am planning on gelcoating the whole inside so i figured i needed to stay away from epoxy, right?

I will try and get some pics soon i know it would be easier to eye up.

I made a couple of surfboards with that extra 6oz cloth i mentioned , 2 ply on top and 1 ply on bottom. Glassed on one sheet and then glassed the other right on top of it. i haven't had a problem of cloth bonding using polyester. then again it wasn't on a boat but i can't imagine it is much difference. I can imagine much heavier cloth would have a hard time bonding.

 

[ondarvr]

Re: fiberglass question

Cloth works OK on surfboards and other things, but you're looking to add strength to a floor that you may have taken some away from. Cloth has very little strength when compared to roving and while it can work, very few boat builders use it because the strength is low and the cost is high.
It's not uncommon to see old boats (or anything made of fiberglass) that have a layer of cloth on the surface that can be pulled off fairly easily, this normally doesn't happen right away, but later on after its been stressed and weathered for awhile. It's commonly used with epoxy for thin laminates and with epoxy bonding is not an issue.

 

[wiz]

Re: fiberglass question

ondarvr, it is not the floor but part of floor. About 4'' of floor up the side and over the rail.. imagine looking from stern down inside boat up to bow then from floor up side over rail looks like this.

i have cut 2 15'long by 2.5'wide sheets of mat and roving to put here with poly resin. Where the bumper and ss hand rail is, it will run from those front seats all the way back to the transom, up over the rail to the outside piece like in drawing above.

.
Sorry i don't have pics of the area in it's condition now.

Not concerned with the mat form-fitting curves BUT will that 18oz roving laydown on the railing curves after it gets wet with resin, corners aren't sharp more rounded?

I have a process question...So i lay mat down, wet out, roll out bubbles and put roving in place, wet out and roll out bubbles, is this correct? Am i getting myself into trouble by trying to do such big peices, 15'x2.5', i'm a little concerned with the working time of poly resin?