glass layup

[adventuris]

hi, i am getting ready to build a 28 ft downeast boat of foam coe construction.i been reading gerrs book on strength.my question is the type of layup his book says would be 2 layers 1808 on outer skin ,this boat being build on male mold ,so can i change to say 3 layers 12 oz cloth would be a lighter and thinner layup but say oz wise of the book states would give me a smoother finish.

[robherc]

Hmmm...

Just my $0.02 in pure conjecture.....
Since 18oz. "woven roving" is cheaper than 12oz cloth, why not use the 2 layers of 18oz, then put a layer of fiberglass "veil" over top of it to smooth out the finish. It'd likely cost you the same, or less, and give you all the strength AND the smooth finish you're looking for.


...Just my $0.02, take it for what it's worth.

[tunnels]

Originally Posted by adventuris

hi, i am getting ready to build a 28 ft downeast boat of foam coe construction.i been reading gerrs book on strength.my question is the type of layup his book says would be 2 layers 1808 on outer skin ,this boat being build on male mold ,so can i change to say 3 layers 12 oz cloth would be a lighter and thinner layup but say oz wise of the book states would give me a smoother finish.

Use what the book says ! 2 layers of a heavyer cloths is better and stronger that 3 layers of a lighter cloth as the lighter cloths have finer weaves and the layers will shear and come apart much easyer than the heavyer coarser weave cloths . You should be using vinylester resin as well as its a stronger resin than polyester .
Now if you are looking for a smoother finish simply use peel ply on the outside and when you are ready to start fairing peel it off and lightly sand the add you fairing compound and then start long boarding .
Peel pyl will give a smooth surface and it also mops up surplus resin and in dryer areas its easy to see air bubbles etc .