After much deliberation about what type of paint to use, I finally settled on Loehle Aero Coatings. The extreme shine, durability, flexibility, and ease of application convinced me it was the way to go. I have seen their demo P-40 painted with their paint system, and it looks great. It's 15 years old! The paint quote I received totaled just under $900 for everything. Compared to the cost of some other systems, I feel this price isn't too bad. ( I actually only used 3 gallons on the whole plane; 1 gal primer, 2 gal color)
The first step in painting is prepping the surface. Instead of traditional alodine conversion coating the surface, I chose PreKote from Aircraft Spruce (Spruce PN: 09-00826). The technical literature states that it is non-toxic, biodegradable, easy to apply, and works just as well as chromates. This appears to be a win-win solution.
After the paint job was complete, I weighed everything that was left from my painting supplies (boxes, packing materials, cans, ect). Since I knew from the shipping label how heavy the boxes were, I simply subtracted the final weight from the initial weight, and came up with 42 lbs. Since I don't know how much weight was lost due to overspray, solvent evaporation, or sanding, I'll just call the final paint job around 30-35 lbs.
Here are a few notes from my painting experience...
I bought the Loehle painting manual and video. The video was a waste of $25! I was very disappointed. It basically shows Mike Loehle painting a test panel....very little about setting up the gun and all the little technical details that you really need. The manual, however, is great. It has specifics and you'll definitely want it.
I used a Harbor Freight HVLP gun, Part #43430, and it took my some experimenting to get things right. One thing I did is to turn up the input pressure MUCH higher than the gun directions said (they said 20 psi). I used 90 psi into the gun, then regulated it down with the built-in regulator to 45 psi. Any lower and the paint would "spatter" out. I also drilled the tip out to 1/64" to pass a bit more paint. This helped a bunch with the thick paint.
The Loehle paint is pretty thick stuff. I followed all the mixing directions, but in retrospect the paint needed to be thinned a bit more. If not, it goes on really nice, then about --5 minutes later, it starts to sag, then run. About the time you start crying, it sets up with nice runs in it :-( I painted a bit dry and let it flow out to smooth. This didn't work 100% and that's why my surface texture is a bit "orange pealed". I think thinning more and spraying less would have worked a bit better, so try this.
One thing Mike Loehle said is that HVLP isn't the way to go with this type of thick paint. A certain amount of air pressure is required to "break up the paint molecules" (his words). My experience confirms this, and the HVLP gun worked fine just turned up to a higher pressure.
The paint would tack up in about 5 minutes, be mostly dry in about 20 minutes, and I was handling it after an hour. The paint is VERY tough, and SUPER glossy! :-) It just looks wonderful (without runs...)! I clear-coated everything after I was done and that was nice too. I definitely recommend that.
I'm sure better results would come from a nicer HVLP gun, although I don't really know which gun to use. I guess that you'd want to spend about $200-$300 for a nice one, but if you know someone to borrow from that'd be better. That's the reason I bought the HF gun....I don't know anyone and the HF gun was on sale for $30.
Loehle sells something called a "nip file". Get one of those....they are great for "nipping" a run without sanding the whole area. It's basically a section of vixen file glued to a wood backing board. Works great!
With any paint, the surface prep is important. The Loehle primer worked great, and when the surface was pre-treated with Pre-Kote the results were great. I love that Pre-Kote! The primer also sanded really easy, so you can get a perfectly smooth surface if you put in the time sanding. I sanded, but didn't get too picky. I wanted to finish, and only sanded a couple of passes. I spent about 3 weeks painting, but like everything, the hours add up quick when you don't really know what you're doing...
After all's said and done, I still really like the Loehle system. It's easy to use compared to Polytone and Aerothane, economical, shines fabulous, and generally gives top value for this amateur builder (me!).
NOTE: photos link to full size image