fiberglass on floor

[KJM]

Hi, I just wanted some advice on laying fiberglass on the floor of my boat. I have it coated with CSM as of yesterday and now plan to overlay that with 6oz cloth to hopefully get a fairly smooth finish. My question is: should I overlap the cloth where cut edges meet or just fit each piece as closely as possible to the adjoining piece? I was thinking overlapping might be stronger but if i then sand it down flat that takes away the overlap anyway, doesn't it? Also will a coat or 2 of jellcoat then smooth out the print of the cloth?

 

[gm280]

Are you laying the 6oz clothe for additional structural support, or merely to get a smoother surface? If for structural support then I would overlap. If you merely going for a smooth surface, butting the fiberglass clothe will suffice. What type 6oz fiberglass are you going to use? Is it more CSM or woven fiberglass like 1708 or whatever weight clothe like that.

 

[KJM]

Its woven cloth. The floor has 1808 underneath and a fair bit of structural support so i was hoping for some structural support but mostly a smooth surface. Do you think a couple of coats of gelcoat on top of that will hide the print of the glass?

 

[todhunter]

From my very limited experience, a few coats of gelcoat will definitely smooth out the edges of the overlap, but you'll still be able to see them unless you sand the gelcoat.

 

[KJM]

I was more wondering about whether you would see the weave of the cloth thru the gelcoat.

 

[Grub54891]

It'll mirror through. Either sand the glass or gel it's up to you. Another method is to lay a thin water resistant filler material over the glass before the gel goes down. Sand that smooth first.

 

[KJM]

Could I make the filler material out of thickened poly resin?

 

[Grub54891]

Yes, it may not lay down perfect but it would work. I'd use cabosil in the epoxy.

 

[JASinIL2006]

I overlapped and it was not terribly difficulty to fair it over later so it looked smooth. The 6 oz. is really thin when it's wetted out.

I personally would prefer to fair using some sort of fairing compound added to the resin, rather than cabosil. Cabosil works, but it is MUCH harder to sand after the resin has catalyzed.

 

[KJM]

I was going to use talc to thicken the resin. I know some say to absorbs water but I can't see how if its soaked in resin.....anyway its above the waterline (and hopefully always will be!) I think I'll overlap a little as you say and fair it up later. Going out tonight to cut the cloth into shape. after this its on to building a splash well and some boxes to put seats on. I might actually get it in the water this year. I bought a yamaha f90 25 inch leg recently. Now i'm wondering if the motor being high will change the center of balance in the boat too much as compared to the inboard she was made for? I guess I'll find out.

 

[kcassells]

I think talcs a great idea. Go for it.

 

[KJM]

Yeah, its talc baby powder (not the corn starch kind), if nothing else I'll have the nicest smelling boat in the harbor.........

 

[kcassells]

Yup your deck will probably never get wet.

 

[JASinIL2006]

Not sure I'd use talc, but it would be easier to sand than cabosil.

 

[KJM]

I might regret it, but I'm going to give it a try. It is sold as a thickener by some fiberglass companies for "above the waterline" applications, so we will see what happens.