I own fuselage #162 of a Monarch D and I would like to now paint it. I notice that along the tail and various places here and there are small indents and bubble holes.

How do you suggest I fill those and how do you suggest I paint it? I want to keep the ship light but I don't compete. Can you suggest some cool colors?

From : Don Stackhouse

Those "bubble holes" are typically called "pinholes" and seem to be present to some extent on most fiberglass parts. On parts that do not have a gel coat on the surface (such as the Monarch fuselage, where very few folks paint them and therefore a gel coat is pretty much just unnecessary extra weight), there will be even more pinholes. Filling them can be an exercize in frustration. If you just try to paint over them, solvent vapors from the paint will build up inside the holes and blow the paint out, opening up the pinholes again. You need something that will get into the pinholes and plug them up.

Two techniques that seem to work are rubbing compound, and primer.

In the case of primer, you first sand the fuselage (which will give your paint much better adhesion, but also open up an astonishing number of additional pinholes!), then apply a sprayed on coat of primer. You will immediately feel sick as you see the disheartening number of pinhols that you hadn't seen before. Get some primer on the tip of your finger and rub it into each and every one of those pinholes. Let it dry thoroughly, then sand off most of the primer (must save weight here, after all!), leaving just the primer in the pinholes and low spots. You amy have to repeat this whole process several imes to make sure you have a truly smooth, pinhole-free surface for your finish paint.

The rubbing compound method is similar, but easier. Just sand the fuselage as before (fine sandpaper, just enough to take the shine off the surface so the paint will stick), then rub the whole surface thoroughly with rubbing compound. The grit in the rubbing compound will work it way into the pinhols and plug them up. You can then seal thew surface with a coat of primer, sand off the excess and aply your finish paint.

Don Stackhouse
DJ Aerotech