Re: is it true that biaxle cloth and epoxy is way stronger then poly?
On some materials it does. Plastics and such, but wood polyester resin and mat is going to be as strong as anything you can put on there. Plus the cost will be much cheaper and will dry faster. I wouldn't use epoxy unless necessary.
Epoxy sticks better on all materials, period. That's just the chemistry of the stuff. There are some things it won't stick to like polyethylene or wet wood, but in any case where epoxy won't stick, poly won't either.
Using a good quality cloth and epoxy on wood is significantly stronger in a composite panel than poly resin and mat. Whether you need that strength is hard to tell for most people. If you're just using the mat to protect against abrasion, then it won't matter.
It's like someone making a ballpoint pen.. it'll work the same if it's made out of plastic, wood, steel, or titanium. Only if you're planning on also using it as a piton for rock climbing do you need to consider titanium or steel.
Likewise you may not need to use epoxy, depending on what you do with your boat, how strong the boat is after repairs, and whether or not it's designed for performance as opposed to general use.
The reason I like to recommend epoxy for amateur boat builders is that it's forgiving... if you have a surface that's accidentally (or due to ignorance) not properly prepped for glassing, poly may not stick hard enough to it to make a good lamination, but epoxy almost certainly will. So if you botch 50% of a critical joint or you don't fully saturate the cloth on your stringers or transom, using epoxy means you may be safe anyway.
Also, epoxy is more waterproof than poly resin. Both need glass to avoid cracking, as mentioned.
Erik
