Any thoughts before I jump into the abyss?

As I stated on my "Transparent Lay-up" web page:

Epoxy
First off, epoxy is weird stuff. It's easy to overlook the obvious, since I've been working with it for almost thirty years. I can't remember anyone talking about this, you just find out the hard way.

Epoxy is thick at room temperature. Mix it up and pour it on a flat surface and unless the surface is PERFECTLY flat, epoxy will run right off an edge. Slowly, but surely! This gets a lot of people in trouble because they want to have a thick coat of epoxy. The novice tendency is to apply a thick coat and find out later, how epoxy drips and runs and flows onto the floor, even though it looked nice and smooth ten minutes ago. The best controllable method of building up a greater thickness is with a number of even thin coats of epoxy.

Laminating with Epoxy

Epoxy is a syrup consistency. Lay-up transparency with fiberglass cloth can be achieved if you can make the epoxy thin enough to totally wet-out the cloth, so all the air is displaced and every fiber is wet. If your epoxy resin is not nearly as thin as water it will not totally wet-out your fiberglass cloth. If the glass has a silvery look to it from certain angles, it has not been totally wet-out.

Some epoxy manufacturers advertise epoxy that will cure at low temperatures. None of these are intended for totally transparent fiberglass wet-out! If you can only raise room temperatures to 70 degrees you may be able to get a decent transparent wet-out of fiberglass cloth with one of the special very thin wet-out epoxies, but you will pay extra for these resins and they are not for weave filling or gluing purposes.

Understanding how to make epoxy thin enough, for a long enough time, is critical to solving the glass transparency problem.

EVERY epoxy is different! Every epoxy manufacturer has a different formula that has qualities that can be an advantage or a disadvantage. For instance, the System Three General Purpose resin I use, with slow hardener at 85˚ is great for glass wet-out. It allows all bubbles to dissipate and results in a transparent lay-up. System Three says I can re-coat up to 72 hours without sanding.

MAS epoxy works well at 80˚ and sets-up in half the time. MAS says I must sand after it is tack free. I've had a lot of problems with bubbles in the fill coats using MAS, even with tipping off or hitting bubbles with a heat gun.

System Three goes on smooth and bubbles are easily removed by tipping off with a foam brush to produce a surface as smooth as varnish.

I'm currently wetting -out my exterior glass and fill coating with System Three General Purpose resin.

I use MAS for interior glassing and gluing parts due to its faster set-up.

System Three resins provide a huge advantage for the home builder, over other resins.

System Threes resins provide a chemical bond for up to 72 hours before sanding between coats is necessary! All System Three hardeners have a longer cure time than other resin systems.

Longer cure time means, more time for bubbles to dissipate, more time to allow the resin to totally wet-out cloth and wood, and this allows the resin to trap less bubbles to begin with curing to a smoother, bubble free surface, requiring less sanding than other resins.

These features make it the best for home builders because, the home builder does not need to rush, or worry about the resin setting-up before they finish application (IF you follow all the methods I outline on my "Transparent Lay-up" page for keeping epoxy thin). And the long chemical bonding window means you can do a seal coat one night, a glass wet-out the next night, a fill coat the next night and so on. This breaks the tasks into smaller, less rushed, easier steps, and reduces variables.

System Three epoxy cures to a smooth surface requiring less sanding.

System Three is not paying me for this endorsement. (But I'd be happy if they did!)
I think this is significant information to make strip building easier for the novice.

This difference only became clear to me a couple years ago when I tried MAS epoxies.

All the best,
Rob