: So here's a little history: 6oz glass supplied with the boat. Came in all
: folded up in a neat little square. So we unfolded it and wound it
: carefully around a cardboard tube. When it came time to lay the glass
: down, we just unrolled it and cut where needed. We poured and spread the
: epoxy with squeegees and everything looked good. Later we could see the
: wavyness when the epoxy was green. It fills up nicely when we use a foam
: brush to pull epoxy into the valleys. I would like to avoid having to do
: this in the future if possible. Is it just the way the glass is when the
: epoxy is not yet set, or can I somehow pull the glass to keep it tight as
: the epoxy sets up??

The waves are likely from when it was folded. Folding can create semi-permanent wrinkles in the cloth that make it lift after being wet out. Actually it probably lifts before it is wet out but you don't notice it as much. Your idea of rolling the cloth onto a tube is a good one but may not have been sufficient. Also you need to be sure you don't introduce any wrinkles when you roll it on to the tube. One high point can propogate a wrinkle into subsequent wraps around the tube.

When shipped a roll of cloth will often have a tag saying "DO NOT STAND ON END". If you stand a tube on end the cloth may settle towards the low end, this will also produce wrinkles and later waves in the lay up. They can be very persistent and hard to eliminate.

Rolling out the glass 24 hours ahead of time can relax the wrinkles a bit, but this is often not enough. I have occasionally hung spring clamps along the perimeter of the glass to give enough tension to get rid of the wrinkles. But you need to recognize the problem while the epoxy is still wet.

If you end up with waves after the epoxy is cured the best solution is to add several coats of epoxy to build up the low spots. You don't want to sand into the glass in the high spots to bring them down. Usually the waves really are not that high so it doesn't take as much resin as it may first appear.