Type of fiberglass

[lp142]

I'm ready to purchase fiberglass for my project, but I still don't have any idea on what to use. I hear all kinds of numbers, can anyone just tell me in simple terms, what to use for the stringers and what to use for the floor?

And a good location to buy it from would be nice too..

Thanks

 

[OhioLowell]

Re: Type of fiberglass

Ip142,

Now keep in mind I'm ignorant! LOL I'm going to use 6oz cloth on just about everything on my boat project. As for how the weights and stuff work I'm not too sure.

I'm sure someone here can help you more than I.

Best of luck!
Lowell

 

[ondarvr]

Re: Type of fiberglass

Cloth is of almost no value when using polyester and mat always needs to used as a first layed to get a better bond.

1.5 or 3/4 oz mat will be fine and get 24 or 18 oz roving, these products are very easy to work with and can be found at Wal-Mart, Kmart, hardware, auto, marine stores and places that sell fiberglass. Other types of glass can be used and are very good, but will cost more and can be difficult to find.

The resin you can buy at those locations will work also, just don't get the thick no drip type, it can be hard to work with. If you get resin with wax in it, you will need to apply the next layup before the first one cures, if it does cure completely, sand it very well before the next layup is put on.

All of these supplies can be found on line, but sometimes shipping cost are very high.

 

[croSSed]

Re: Type of fiberglass

Here's a GREAT resource:

fiberglasssupply.com/

They have good prices and are very helpful. They were nice to me in my ignorance.

TG

 

[Realgun]

Re: Type of fiberglass

The best tip is to not over wet the glass product with epoxy/polyester. The fibers are the strength not the binder. To glass stringers and transoms use roving and mat. For floors use a 6 oz cloth. Best way for strength and light weight is to "tape" the edges of floor to hull first with a 6 inch wide strip. then comback with a 12 inch wide strip. Finally over the entire floor lay the cloth from side to side. Use two coats of epoxy/poly and spred it thin!

 

[OhioLowell]

Re: Type of fiberglass

Is roving and mat the same thing? I know that's' a dumb question but I'll ask it anyway!

Lowell

 

[jddenham]

Re: Type of fiberglass

Go to fiberglassics.com and they have a nice section on fiberglass types.

 

[ondarvr]

Re: Type of fiberglass

Mat is the fuzzy stuff, many short strands bonded together. Roving is a woven product, large fiber bundles not stitched or bonded together, just woven, it will conform to odd shapes fairly easily.

 

[Boomyal]

Re: Type of fiberglass

Mat is the fuzzy stuff, many short strands bonded together. Roving is a woven product, large fiber bundles not stitched or bonded together, just woven, it will conform to odd shapes fairly easily.

How is roving different than cloth?

 

[OhioLowell]

Re: Type of fiberglass

Cloth is of almost no value when using polyester and mat always needs to used as a first layed to get a better bond.

I'm not trying to be a terd here, but I've read several "stitch and glue" books and I don't recall them using any mat in any of the taping or glassing. I may be wrong but I don't think so.

I'm not questioning to stir the pot. I really want to know if I need to lay mat before I lay the cloth over my new transom or will just 2 layers of cloth accomplish the same thing.

Thanks!
Lowell

It just occured to me is the difference that in stitch and glue you're using mostly epoxy and not poly?

 

[Frank Acampora]

Re: Type of fiberglass

I never really got into fiberglass so you piqued my interest. Why is cloth of almost no value with poly? Strength issue? wetting issue? Elaborate please.

 

[ondarvr]

Re: Type of fiberglass

Cloth is more or less just a finer woven roving, but the cost is high for the strength it adds to a layup, there are a few things it does well, but they are few, not many boat builders use it, and almost never for strength.

OL, Correct
You slipped back into the wooden boat mode again, they use epoxy and need to use cloth and it works very well with epoxy in that application. Most mat is not compatible with epoxy, so it shouldn't be used with it unless you get the correct type. Polyester does not bond as well as epoxy and when you use cloth or roving as the first layer you will get a very poor bond. Many times you can pull it off fairy easily if you can grab a corner of the cloth. This is the reason many people think epoxy is the only way to repair a boat, they've done or seen a repair done with cloth, too much resin and poor surface prep, this type of repair will almost always fail.

There is nothing wrong with using epoxy to repair a boat and sometimes it's the best thing to use, but for the vast majority of repairs you will never notice the difference between the two.

 

[Solittle]

Re: Type of fiberglass

Re roving vs. cloth- cloth is much like course burlap while roving is like a thick version of the cane used in the seat or back of an old fashioned wicker chair. Each has it's application depending on what you want to do. Try Google & read away.