paint comments
Steve,
I stumbled on to this thread by accident. Otherwise I would have commented sooner.I have really enjoyed your comments and pictures on your process.
When I started my painting journey I could not get anyone who had gone before to give me any tips on using Concept so I went through much of your trials and tribulations with the paint and more.
Here are my comments for anyone contemplating painting their own plane.
Paint Booth.
10 foot width is too small. Mine was 10 x 20 x 8. Too narrow. Once you are painting PPG in full suit and fresh air system, getting around the booth is a major aggravation. I did mine inside a T hangar so I had no choice. But I made some compensations.
I think most people over think the inflow/outflow business. I used 5 20/20" pleated furnace filters for intake high on one end and a cheap box fan (gasp explosion hazard!) low on other end. The fan was adjusted so that there was some airflow but I was not sucking air from unwanted areas. When you are painting only parts of the plane with an HVLP gun you won't generate that much overspray so it was not a problem for me.
Here is a picture of doing the wings. Notice the narrow width. I had to rotate the wings to do the paint then rotate them upright to get around them. There is very little room to do the back of the surface.
Doing the fuselage.
I commandeered a derelict rotisserie used to make dirt-track race cars to be able to rotate the fuselage. 45 degrees from horizontal allowed me to lay down an even layer of paint from one side. Use cheap plastic drop cloths for the floor and wet them down thoroughly before painting. No dust and paint does not stick to floor. Here is the rotisserie and the narrow quarters.
Fuselage painted and cleaned up.
I used PPG primer. It would orange peel very easily. I found that thinning it with acetone (per instructions) helped quite a bit. If you leave any irregularities that occur in the primer they will be magnified by the paint coat.
Paint
PPB Concept was a great choice for me. One step process. Less weight. But very expensive. Able to cut and buff the errors out. Forget the standard "you have to do a flash coat to keep the paint sticking and not have any runs." BS. I had the best results with just full two coats of paint. Apply til you think its going to run. Apply to horizontal surfaces(real important). Adjust your part to make it happen. By the time you have put the first coat on the part and refilled the gun, its time to do the second coat.
I had a big problem with orange peel before I learned the tricks. If you use too fast a reducer or spray from too high, or go too fast, you will get orange peel. The first day it looks like it is flowing out but then the paint will begin to really dry and the orange peel will come back. I had to force myself to slow down and let the paint really flow out of the gun to get a good wet coat. Check the temperature and stick with the reducer recommended for that temp. Err if any on the low side so it doesn't come out dry. In my experience 8" is way to high for the gun to be above the surface. YMMV. I may have added just a little extra reducer to thin the paint, I can' recall. Didn't use a viscometer??
I talked with PPG reps a couple of times. As IR, you have to wait one,two weeks before doing any cut,buff, or polishing. The rep told me to get it all done before 90 days, but I have done some long after that with decent results. The cut, buff and polish will change the appearance of the paint job, so unless you are doing some kind of clear coat, you cannot just buff an area. The cutting process destroys some of the really nice depth look of the Concept paint. The result is not unacceptable just different. So take that into account.
I have 5 HVLP guns, all cheapos. They all work. The horrible freight gun that I got when they were still made in Taiwan is the best of the lot. If I had to do it over, I would get a better, high quality gun.
I used a final disposable screw-on water filter just below the gun. No water problems. My 33 gallon tank was not enough. You need lots of air so that the pressures stay constant till you can stop and let the air compressor catch up.
Dave A.