Stringers...what kind of glass and how much???

[i_Adam_i18]

Well I just bought a 1966 Larson 15.5 foot fiberglass boat. The deck was rotton so I ripped it all out and am planning on replacing that and the stringers.

Only, I have no idea how much glass, what type, or how much epoxy resin I need. I want to resin the plywood and glass the top (what kind of glass?) and then I need to tie the deck into the hull (what kind of glass there?). I know I want to make sure the deck is glassed in strong and waterproof so it helps in the rigidity of the boat. How many layers of glass and what kind of glass should I use to tie the deck into the hull??

 

[tlovelandka]

Re: What kind of glass and how much???

Re: What kind of glass and how much???

Welcome to iboats Adam!

There's a lot of different ways to go about laying down glass. I recommend you read Oop's hull extension thread. There's a ton of info on there, and you'll learn a lot.

I'm not an expert on glass, but I can tell you where to find the info you're looking for. You can always use the search function, but I'd dig into some of the longer threads on here and read about how those guys did there's.

Good luck on your build!

-TLove

 

[drewpster]

Re: What kind of glass and how much???

Re: What kind of glass and how much???

The answer you are looking for is fiber-glass. Just kidding.
The truth is that you can use any kind of fiberglass reinforcement you want with epoxy. Some say you cannot use Chopped Strand Mat with epoxy because the binder in the CSM is not compatible with epoxy. Personally I think that thinking has gone away with modern CSM. I have used CSM with epoxy and had no problems with it.
The point with epoxy is that it bonds better and cures much stronger than Polyester or Vinylester resin so less fiberglass is needed with it.
Generally speaking you do not need CSM with epoxy. Woven Roving or cloth will work fine with epoxy as long you are not working with tight angles. The kind of surface you are trying to build matters also. If you want a thick layer of fiberglass covering a thinner core, then use heavier weights. If you want a smoother surface that is easier to prep for paint then you want to use lighter, tighter woven cloth.
Again, generally speaking, any woven roving up to about 18oz. will work for a deck. Use light cloth as the final layer to give a smooth paint friendly finish surface and your golden.
There are calculators out there to figure how much resin you need for a given amount of cloth. The amount of cloth you buy depends on the surface area you want to cover.
An example
My tri-hull got a new transom and new stringers so far.
15 yards of 1.5oz CSM
25 feet of 12" 1.5 CSM tape
9 yards of 18oz. woven roving
10 gallons of Polyester resin All used so far! And the deck is not down yet!

Considering polyester resin yet? Much cheaper than epoxy.

 

[bigredinohio]

Re: What kind of glass and how much???

Re: What kind of glass and how much???

An example
My tri-hull got a new transom and new stringers so far.
15 yards of 1.5oz CSM
25 feet of 12" 1.5 CSM tape
9 yards of 18oz. woven roving
10 gallons of Polyester resin All used so far! And the deck is not down yet!

Considering polyester resin yet? Much cheaper than epoxy.

Not to hi-jack the thread but what brand poly resin do you use Drewpster and/or where do you get it? I'm working with US Composites and System Three epoxies but I want to do some f-glassing modifications to the hood/windshield/dash and want to dabble with poly (mostly so I can gelcoat).

 

[drewpster]

Re: What kind of glass and how much???

Re: What kind of glass and how much???

US Composites - 435 layup resin and related products.
I use MAS Epoxies from a local supplier.
I have never used System Three, but allot of folks in here like it.
West System is good stuff, but pricey.

 

[i_Adam_i18]

Re: What kind of glass and how much???

Re: What kind of glass and how much???

Well I've got some 1708 biaxial on the way, will just that work to do the stringers? and how many layers? I was going to use 3 layers (2, 4, and 6") of the 1708 to tie the deck into the hull, will that be strong enough or should I use something else in conjunction?

Also, this boat is pretty strange on stingers. There is one stringer running down the center that appears to be a normal size, but then on eather side, there is a (approximately) 5" tall by 10" wide by 9 foot long stringer wrapped in glass. I cut the top off to find a 1" x 10" x 9' solid board on top of foam.

I let pulled the boards off and let the foam dry (it dried out pretty quick) and am planning on just replacing the solid boards and glassing back over the whole thing. does that sound right as far as rigidity of the boat goes? I don't think there is another stringer buried under that foam, so it must just be the fiberglass shell that was acting as the rigid support, before I cut the top off that is. And I think the solid boards are just something to bolt the seats to. What do you guys think? Also I have some 1" x 10" x 8' solid walnut thats already been drying for a couple years. I wonder if there would be a problem with using those and having a foot less of solid wood. Any opinions?