The House Of Balsa Dust

Fiberglass skins the easy way

Everyone wants a glass-smooth surface for painting, but getting one usually involves a _lot_ of sanding, sanding, SANDING !

I think sanding is APITA.

One way to achieve a glass-smooth surface is a fiberglass skin, which is easily made.

All you need is a flat glass surface at least as large as the skin you intend making.

Wax the dickens out of the glass surface; no such thing as too much wax, and use a good paste wax (not Pledge). Get a good shine going.

Cut the glass cloth (preferrably .58 oz) so it hangs over the glass work surface on all sides by a couple of inches.

Mix up a batch of your favorite finishing epoxy and thin it with acetone. Denatured alcohol works too. Don't use isopropyl drug-store alcohol - it's about 30% water. You want the thinned epoxy 'watery-runny' so it saturates the glass cloth thoroughly.

Apply the thinned epoxy however you prefer, but a brush works ok if you're careful not to snag the glass cloth. A small foam paint roller works well too.

Coat the glass cloth with the >thinnest< layer of thinned epoxy you can manage, then blot up the excess with a roll of paper towels.

When the first coat of epoxy has cured (may take a day or so), apply and blot a second coat.

When the second epoxy coat is cured, simply lift the epoxy-fiberglass sheet off the glass work surface and trim the edges as needed.

You'll find that the underside, that is, the surface which was against the waxed glass, has a paint-ready glass-smooth finish.

Bond the fiberglass skin with your favorite skinning adhesive. The .58 oz cloth/epoxy skin is quite flexible and will follow most contours (although I haven't tried to wrap it around a leading edge).

The fiberglass skin is best suited to finishing wings and fuselages, but the stuff is also thin enough to scissor up for access hatches and panels if you're so inclined.