Finishing balsa covered model?

IF you have the time and patience, this system does work.

First of all, fill every hollow and ripple with lighweight filler, or even dope and talcum, or microballoones.

Now sand it down perfectly. Yes perfectly.

Coat one clear dope 50/50 thinned coat, and sand again but lightly, just to take out the brushmarks

Dope on one layer of lightweight tissue. with 50/50 thinned dope.

sand again.

Maybe dope and sand again. Now you have a hard coated shell, that can be sanded without going through to the balsa. Mostly :-)

If the finish looks good enough, get about 20 cans of cellulose based car primer on grey. Spray, then rub down wet with wet'n'dry until the wood color shows through in patches. Repeat until there are no pinholes, ripples etc. etc. left. This takes DAYS. You Can use filler primer as well - this dries thick and a bit soft.

Now just spray your bird with *enamel* matt base undercoat, followed by enamel top coat. If this screws up and dribbles, sand down to undercoat and try again...and again.

Eventually you will have the prettiest - and heaviest - bird on the flightline :-)

Stuff more watts/cc's in the front and fly it anyway.

1) paint the wood with well thinned down non-shrinking dope (NON-SHRINKING!), eventually thickened with gel medium and talcum powder. Sand lightly between coats to remove the lifted, and now fixed wood fibres. 2) Apply two more coats of same, sand lightly in between.

This is the quick and dirty base coat.

3) Using thinner, brush patches of moistened paper/tissue/nylon/polyester nonwoven scrim (choose between one) onto the prepared surface. Eventually, rub down lightly with dope impregnated tissue, to get out all wrinkles. Use light materials of less than one ounce/yard

4) fill the weave with two more coats of non-thinned non-shrinking dope, again sand lightly, this time after the last coat only, unless you want to raise fibres of the paper/tissue/nylon/polyester nonwoven scrim

Finish: Here is where the real work may start. You can either make quick jobs and get decent results, or be tedious, and get excellent results.

Quick: Don't care about slight imperfections, and finish off with Humbrol or Revell, topped with methanol thinned epoxy. The finish is clear and shiny, and may even be applied over transparent canopies. The plastic model paints are available in all colors, and can be used sparingly, whilst drying to extremely thin films. This finish stands up to wear and fuel quite well, depending on the number of epoxy coats. If well thinned to watery consistency, weight increase is extremely low, The resulting finish beats cover film in weight, and stands up to 6 feet off judgement. It takes more time to write this, than to do it.

Cumbersome: finish off with automotive wash-primer, which serves as adhesion interface to the dope. Now apply all sorts of intercompatible coats that the car paint shop guy advises you, sand and fill and sand and fill and sand and fill as you see fit, and finally apply the number of top coats needed to get the desired finish, eventually rubbed between coats. That may be as many as 15, depending on pain types used. This is not quite as light, and it is a shame to fly a plane finished like this. Let it sit in the pits, and fly your plane that is finished in the quick and dirty way. That way, you'll enjoy both :-)

Glass cloth and resin. Lots of work (sanding) but worth the effort.

On 7/15/2003 11:15 AM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

Use a 50/50 mix dope/thinner. Dope on ONE layer of MEDIUM weight silkspan. Let dry. Feather the edges with some 320 or 400 (wet is preferred). When the edges are feathered, LIGHTLY sand the bird with

400 used wet. Use the 50/50 mix again and add an additional 25% talcum powder. Mix EXTREMELY well and brush on a THIN to MEDIUM coat to seal the silkspan. when dry sand with 400 wet. Prime with auto type SANDABLE primer. When dry sand with 600 wet. Now apply your paint (preferably by spraying). Latex works very well, is cheap and can be EXACTLY color matched. Let dry for about 10 - 14 days. Now apply a fuel proof clear coat. Lusterkote clear is good (If you do not heat the can in water you may not get a decent finish) and OIL BASE polyurethane (good to about 15% nitro) is also good.

If you can find an OLD TIME AUTO PAINT SHOP/SUPPLIER, have them mix ACRYLIC LACQUER to your colors. Acrylic lacquer is fuel proof.

Thanks for the info. You all seem to be very meticulous. This gives me some options.

Thanks again

Gary