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.

 

Usually, E-glass works fine for making canoes unless you're aiming for a racing boat, where S-glass might be better. Just bear in mind that S-glass costs more. Most canoes are made from biaxial fiberglass fabric.
I am yann，from inry fiberglass cloth manufacture

 

E glass is by far the most common.You can occasionally locate S glass,but it is very rare and most people these days seem to like boasting of the presence of carbon in their laminate,whether it needs it or not.For an amateur built boat it really isn't worth making a huge effort as the designer will almost certainly have assumed E glass will be used and will have incorporated enough of a safety factor to accommodate the probable skill level of an amateur builder.I'm not too surprised at the huge disparities in price as somebody has to pay for those full page colour ads in the boating magazines.To help with selecting a good one,there is nothing to compare with asking a local builder which works in local conditions as you will be working in those same conditions.If the resin is mixed properly and cured completely they will all be much stronger than the wood you are bonding.

 

As wet feet said, e-glass is far more common, less expensive and generally what you would expect unless the plans specifically said to use s-glass.

The epoxy property that concerns me for a hand layup is the viscosity. 11,000 cp is too thick to work with. Honey has a viscosity of about 10000 cp. It will be very difficult to handle. West is around 900 cp. The price is also baffling. I don't know how they can make any money.

The mechanical properties are low, assuming the units are psi. That is not to say too low, but on the low side. The data sheet lists some properties without units and some in kg/cm^2.

https://www.tri-iso.com/documents/Kukdo_EPOKUKDO_YD-128_TDS.pdf
https://5.imimg.com/data5/HR/FD/MY-117280/standard-liquid-epoxy-resin-yd-128.pdf