Painting the Interior

NOTE:  photos link to full size image

I decided early on that I was going to paint the cockpit area. The main reason for this was because I planned to prime all the cockpit pieces. Unfortunately, this would look terrible as a finished cockpit. It might be possible to upholster the cockpit, but this seemed impractical and excessive. I wanted something to cover up the primer as well as provide a tough, wear resistant finish in the cockpit. I settled on Randolph 2-part epoxy white primer. Not being sure about the quantity of paint required, I ordered a one quart kit (included paint, catalyzer, and reducer) from Aircraft Spruce for around $50. This turned out to be not quite enough to get the job done, and I ordered a second quart.
I purchased a Harbor Freight HVLP spray gun based on several recommendations. I am actually rather impressed with it, considering it was on sale for under $40. It only comes with one size needle, and I believe it is around 1.6mm (it's big anyway). I am running 1/2" hose with large diameter fittings into the gun, with the compressor set to 90 psi. The gun regulator reduces this to 20 psi, and I have the air flow adjustments set near maximum. With this thicker epoxy paint, it seems to do pretty well.
To help refine my spraying technique, I started on the less visible pieces in the baggage compartment. I also used a section of scrap 0.032 to answer some questions about surface preparation and cleanliness.
The test piece was not cleaned or scuffed prior to spraying. There was apparently some contamination present because the paint fisheyed almost immediately (I darkened the picture to show this.)
Even after applying the second coat, the effect of the fisheye was still very noticeable.
I decided to go ahead and spray the baggage compartment sections and a few test angle pieces. The angles were good practice for the cockpit area (there's lots of angles up there). One was merely sanded and scuffed (from the scrap bin) and the other had been previously primed with zinc oxide. There was no noticable difference in the way the paint went on the two angles, and coverage was good.
The second coat was sprayed 15 minutes later, and looked good. The paint is a 2-part epoxy, and while it is catalyzing it get a bit rubbery. It is important to leave it alone during this stage (I know....).
The second coats went on the baggage pieces nicely. Except for dropping the part onto my plastic drop cloth, there were no problems. I used 1 cut of catalyzed paint, thinned it 50% as recommended, and was able to spray a total of 20-25 sq ft.
This is what semi-catalyzed epoxy paint looks like when you try to peal it off....not pretty. I'll let it dry and then sand it off.
To spray the cockpit area, I set up a temporary paint tent in the driveway. The inside is lined in thin plastic sheet, and the outside is covered in tarps to break the wind.
The booth only needed to be big enough to get the front in, so that's all I made :-) After the spraying is done, the 3 plastic drop cloths are balled up and thrown away (they're only $1.50 each!), and the tarps folded up for use later. Aside from the setup/teardown time, the tent is great.
After the wings were rigged and the spar tunnel closed up and riveted, the interior can be sprayed. I sprayed two light coats on the inside. Unfortunately, the cramped space and awkward angle of the gun caused a couple of very noticeable runs. I sanded the runs out and will touch up those areas with a second coat. Total paint used was one quart, and this stuff is hard after a couple of days curing! Prior to that, lacquer thinner cuts it pretty well.
The second coat is on, and the cockpit area is done! Now I'm ready to install the controls and start closing the cockpit area out.


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Updated: 31 Dec 05