Would S-glass be clear/translucent when put over another cloth such as kevlar. If you can see through the S-glass, would the underlying cloth be clearly visible or “fuzzy” looking

It depends…
…on the weight and weave of the glass. S-glass typically does not wet out as clear as E-glass, but you can still see through it. You just may see some of the weave.

S-glass does not wet out clear like

– Last Updated: Nov-03-09 12:38 PM EST –

the commoner E-glass. I think the Kevlar weave would not be clear when viewed through the S-Glass and resin. Unfortunately I can't be clearer (!) because all of my glass-over-Kevlar boats have an outer color coat. I'm going to see if I still have a link for a boat builder who discusses various cover fabrics for wood boats. He also noted that S-glass does not wet out clear.

Here's the link, with some pictures. It's too long to just click, so highlight, copy, and address.


that was my experience with S glass
… on the inside.

In fact, until you just spoke of a difference in transparency between S glass and E glass, I figured mine wasn’t clear because I didn’t do something quite right.


Yeah, what I’m using now is a very
tight satin weave. It is hard to wet out. An ordinary 4 oz flat or round weave would wet out clearer.

certain epoxy types are clearer than …
… others . These types are made just for that purpose of being crystal clear .

Absolutely true, like West 207. But
with S-glass, the problem is that available weaves are quite tight and don’t wet out clear.

I think it’s the index of refraction
the chemical composition of s-glass is different

That could be part of it, too.
I don’t have a microscope, or I would examine E-glass and S-glass fibers.