Boat Builder Central - Builder Forums

I’m doing a few non-structural joints on my build, so I got some woven tape thinking it would wet out easier than biax. It doesnt, (though it doesn’t seem any harder either).

If I’m not mistaken, biax is stronger, so if it doesn’t wet out easier, and it isn’t stronger, what are its advantages? Is it more abrasion resistant?

Jbo

It is easier to fill and fair.

If that’s it’s only real benefit, there’s still really no reason to use it.

Other than maybe to prevent checking.

Jbo

Stiffness is a function of thickness. Thicker tapes are stiffer. Also less snaky for table wetting and moving.

Weight and epoxy penalties are severe.

Not to be a jerkface, Fall Guy, while I agree, I’m not sure what that has to do with the question(s). ?

Though I did experience the “snakiness” problems you mention during my last laminating session.

Jbo

Oh. I misread. I thought he meant with mat vs without.

Woven tapes are thinner, less stiffness, easier to finish.

woven tapes wetout easier and down through, biax won't because it is two layers...

jbo_c wrote: ↑Fri Oct 28, 2022 12:39 pm If that’s it’s only real benefit, there’s still really no reason to use it.

Other than maybe to prevent checking.

Jbo

The way I see it is this:

Woven tape has finished edges that don't get messy while wetting it out. Biax tape does not, at least not any of the the stuff I have used. Those edges may require feathering afterwards, so they are not always desirable. If I need to glass something where I want the edges feathered, I'll use cut cloth, not tape. Probably.

Woven cloth(tape included) doesn't have the binding string that biax tape has. That string needs to be sanded down before fairing to avoid the need for excessive fairing material , something I learned the hard/expensive way.

So, If I'm glassing a surface for abrasion/checking alone, I'm never gonna reach for biax, unless it's all I have.

I didn’t find it to be especially easier to wet out.

I definitely agree it should be easier to finish. I can’t decide whether I think it should be more or less abrasion resistant and I haven’t seen anything that suggests it’s either.

I don’t find the stitch in biax hard to deal with, but it does have to be dealt with.

Jbo

I used 6oz cloth on my kayak. With a couple of extra coats of epoxy then varnish, it shows the wood grain perfectly. If you want a bright finish on something, cloth is the only way to go if strength isn't an issue. Biax is murky compared to woven cloth. If painting, use whatever you have.