My current finishing method is Certified or Randolph color with automotive toners added to get those colors no available off the shelf, talc filler/sanding sealer and final coat of Automotive Clear coat. The result has been 18/19 points under some very critical judging.
Here's the process:
Sand all bare wood smooth with 320. Apply 2 brushed coats of Clear thinned 30%.
Sand lightly with 600. Cover all wood with .02 oz. carbon veil. Apply 2 more
brushed coats of the same clear mixture. Again sand lightly with 600.
Pour some full strength clear in a large container with a good sealing lid. Now dump in as much Talc as will stay suspended in the dope (allow about 10 minutes to settle) Next, very important step is to mix in a small amount of Black dope, just enough to make a very light gray. The very best Talc I have ever used comes from Tap Plastics. It has no odder or oils. Next, thin this mixture only enough to get it through your spray gun. I use a big ugly gun with pressure feed, they're cheap and readily available at Sears. Spray on a medium heavy coat of this stuff. Let it dry a day. Now here's the really cool part. You're gonna sand off 80 to 90% of this and you'll hardly break a sweat! This stuff powders like crazy! It took only 3 hours to sand an entire classic ship leaving only enough to fill. Now since this mixture is gray you will be able to tell the low spots and areas that need more work. No need to get out the spray gun, just spot these areas with a brush and sand. Once everything is uniform thin some clear dope 80% that right 80% and spray on a quick wet coat!
Color: Thin all colors 50 to 60% with and spray on dry. Just enough to cover,
don't worry about shine, blushing or even being a little rough. Once all colors
are on. Spray on 2 coats of clear thinned 60%. Again don't worry about shine
or blush. Lightly sand everything with 800 wet being careful not to sand through
the clear coats. Finally once everything is sanded CLEAN EVERYTHING WITH WINDEX.
CLEAN IT AT LEAST 2 TIMES USING WINDEX. I usually do this procedure 4 times.
Degreasers such as Prepsol or AcryliClean don’t get the job done. What
you really want to do with cleaning is remove everything that is not fixed permanently
to the surface. The reason for all the cleaning is I discovered that just about
all of the dust particles that end up in the clear coat are on the plane to
begin with. Very little comes from the air. Once you have cleaned and re-cleaned
go over everything with a tack cloth several times being careful to apply only
light pressure.
Now you’re ready for the main event. Lightly apply 1 coat of Automotive
Clear. I use PPG Global Performance System Clear D893 and D871 Medium thinner/reducer
(this is very different stuff from the DAU 75). This is a 3-part paint, clear,
catalyst, and reducer. I use 50% reducer to get a water thin mixture. I also
use a gravity fed touch-up gun to put on a very light but even coat. The PPG
is dust free in about 10 minutes and the model can be handled in about 2 hours.
Your plane will shine like glass at this point and depending on how much dust
you have in your spray area you just might be finished! If there is dust fear
not. Wet sand with 1200 or 1500 (which ever you have the patience for) and rub
out. This whole process added 9 oz. to a fairly large 750 sq. piped ship that
has a lot of fuse, rudder and cheek cowls. It only took 6 oz. for my Vulcan
classic ship. While I've heard of 4 to 6 oz. finishes by others I have never
been able to get it that light no matter how hard I try. The weight of this
is quite reasonable and very fast and easy. Hope this helps.