E-Glass vs S-Glass + Epoxy Specifications

Hello,

I would be happy to know, what glass type and weave are usually meant in plans for self building a plywood boat.
For example - if in the materials list written 220gr glass, what is the glass type (E-Glass or S-Glass) and weave
(Twill, Bi-Axial 45-/45+, etc...) should be used.

Another question is regarding epoxy specifications. There is an extremely cheap resin sold in my area named
KUKDO YD-128, which is 4-5 times cheaper than other brands. But the specifications are 30% weaker.
Would the numbers suffice for a small build, or should the best available epoxy used?


Thanks alot,
Eli.

 

S glass is 40% stronger and 20% more flexible than "standard" E glass. However, it is cheaper to buy E glass that is 40% heavier despite the extra use of resin. Compare the strength and modulus of your resin, to the plywood you can obtain. Quite often, the resin exceeds the wood fibres by some margin.
Bi-ax is often used on stems and chines, but also by some for entire hull sheathing, it often depends on the underlying frame work and ply hull skin thickness. The majority of ply-on-frame builds i have constructed used just plain weave tapes and cloth, all E glass.
If you are aiming for ultimate light weight, then S glass may be worthwhile, at a price.

 

Thanks a lot.