This is how I do it:

If you have a Home Depot nearby, check the paint aisle next to the paint brushes for a paint roller blister pack made by "Shur-Line"; they are in a black package with a green stripe. You will find two white 1/8" knap roller inserts and a plastic red handle in the package. The blister pack doubles as your epoxy tray.

Mix your epoxy in a cup following the manufacturer's directions. Pour it into the roller tray that is actually the blister pack. Load the roller, apply it to the wing like paint; it will soak into the balsa. If you need to, mix more right away, you should be working with resin with a long cure time so if you mix two batches within 5 minutes of each other it should not be a big deal.

Carefully stretch out the glass cloth over the wing and lay it on top. It is not necessary to lay the cloth evenly over both sides to keep it from sliding off, as the wing is already sticky with resin. You can now use the Shur-Line roller to apply resin to the cloth as needed. Work out bubbles and wrinkles with the Shur-Line roller.


When you finish, rotate the wing catching the reflection of the sun or lights in the wet resin. Inspect the entire tune in this manner. You should see the weave of the cloth. If you see shiny spots, roll the roller of a few layers of paper towels, then use it to mop up any excess resin.

When the glass has cured, sand it with 120 grit and wipe it down with acetone or lacquer thinner and a clean rag. Follow appropriate safety precautions when sanding cured fiberglass and using solvents.

To fill the weave pattern of the cloth so that it is smooth, "Kilz" is a high-solids primer in a spray can that will fill the weave and sands easily. Home Deopt carries Kilz in the paint department.