Dow pink foam /fiberglass composite !

[Andris Golts]

Hi all i am in the process of building a 18 inch micro catamaran my sponsons are cut and sanded from Dow pink foam and my standard method of construction is to sheet all 4 sides in 1/64 birch aircraft ply but due to the price of the 1/64 ply increasing 4 fold in price here in Canada i decided i will sheet the sponson bottom and inside with 1/64 ply and cover the top and outside with 2.4 oz fiberglass cloth and Pacer finishing resin . My question here is how many layers of 2.4 oz cloth and resin do i need to apply to = the strength of the 1/64 ply that has been glued with epoxy ! Regards Andris Golts.

[ray schrauwen]

4 Fold!!! WOW. I'll never sell my Whiplash kit up on my shelf. Sorry, I'm lost with FG. IF I was in Milton I would give you some 1/64 ply.

Take care.

[Jesse J]

Assuming you mean fg cloth, it depends on the weave. The finer the weave, the more layers. Also, the finer you go, the more you need to thin the epoxy, or it wont permeate the cloth. Thin epoxy tends to be a little more flexible.
I’d be inclined to go with heavier coarser fg and be ready to fill in with bondo glazing.
Still pretty light but strong. And with some careful sanding, ends up very smooth.

[larryrose11]

the cheapest way to increase the strength of fiberglass is vacuum bagging to squeeze out the extra resin.
I have seen it done on the cheap a vacuum storage bag. If I were to go this route, this is what I would do, in order of layers:
1. wet hand lay up, several layers or more depending on thickness.
2. Peel ply layer. Hold in place with thin tape, as it directly affects the final outer shape.
3. Three or four 4 paper towel layers over the top as a breather ,
4 Put the whole thing in a vacuum storage bag,
5. Put a shop vac on it, left running for an hour or two.
Heat would be your friend here. a shop light to get it warm will help thin out the epoxy quite a bit, it will also cut the cure time by a factor if 4 if you can get it to 120 F.

[Andris Golts]

Thanks to all for the great information. Regards Andris Golts.