How much fiberglass does it take

[nastyquedawg]

I am in the process of trying to determine how much fiberglass mat and cloth i need to restore my 21ft center console. The beam of this boat is 8ft.

The scope of work consists of the following
1. Fiberglass back side of transom with 2 layers of mat, 1 layer of cloth.
2. Fiberglass 2 16ft stringers
3. Fiberglass the floor with 1 layer of mat on the bottomside of the floor and 1 layer of mat and 1 layer of cloth on the topside.

I have determined that I need about 62 cubic yards of mat and about 42 cubic yards of cloth. Is this amount of fiberglass typical for a restoration? Also what is a good online site to purchase this amount of glass? I just want to make sure I am in the ball park before I purchase anything. Thanks

 

[oops!]

Re: How much fiberglass does it take

add another 10 per cent...

plus add 5 yards of 1708 bi axe.
5 gallons acetone and 10 gallons of poly or epoxy...your call

cheers
oops

 

[erikgreen]

Re: How much fiberglass does it take

Well, first... it's not cubic yards, it's probably square yards you want, or possibly running yards. Cloth and mat are typically sold at roll width, so you may get 38 inch or 50 inch wide yards depending on what/where you buy.

Assuming you go with the layup you intend (which by the way seems light for a 21 footer) then you can get your mat and cloth cheaply by ordering online from www.uscomposites.com.

If I were doing a boat that size (and I am) I'd do a poly layup as follows:

3x layers, 4 ft by 8 ft (transom,9 yds 1708)
2x layers of tabs on stringers + 3rd full cover layer (24 yds 1708)
1x layer mat on deck bottom - about 18 yards mat
1x layer 1708 on deck top - 18 yds

Total: 52 yds 1708 + 18 yards mat (50 inch) $442+$62=$504

1708 is a stitched fabric/mat combination. It doesn't unravel, and is easy to cut to shape and work with. Highly recommended for poly resin work, where you have to use mat in between layers of roving or cloth.

If you want to use cloth/mat separately, then just plan on 1 layer of mat and 1 of cloth instead of each layer of 1708, like so:

With mat/cloth: $203 of mat (70 yds) and $358 (52 yds) 10 oz cloth
=$562


Just for comparison, you'd get at least the same strength with an epoxy layup like this:

33 yds (18 oz e glass, transom + stringers) $281 + 36 yds (7.5 oz cloth, deck) $157
=$438

Since you don't need mat for epoxy. The epoxy layup looks cheaper, but you have to figure in the epoxy cost. From US composites, epoxy is about $50 a gallon, where poly is about $20 a gallon (plus shipping).

For the layups above you'd need about 10-15 gallons of resin, depending on how much is wasted.

If this is your first resto, I'd recommend going with poly resin and the 1708 cloth for everything but the under deck layer. It'll be easiest to use and quickest since you have fewer layers to cut to shape. Check your local shops, if you can pay $125 or so for 5 gallons of poly resin that'll be cheaper than shipping it.

I wouldn't recommend your listed layup.. it's just too light for that boat, assuming it's a fairly "normal" fiberglass hull.

Erik

 

[nastyquedawg]

Re: How much fiberglass does it take

Thanks Erik, this info is greatly appreciated