How much door gap for paint?

[andrewtac]

My doors are hung and swing well. I am using the Van's seals. I am trying to finish the body work on the doors and cabin. How much of a gap should I have around the doors prior to paint? I'd like to finish them out, pull them, paint them, then put them away for final assembly.

[lr172]

Depending upon the paint, the film depth should be under .015" However, you will want a gap of at least 1/16 or 1/8", after paint for other reasons.

[andrewtac]

So 1/8 gap, and after paint it should be no less than 1/16 (assuming 0.015 paint depth).

[AdamB]

I shot for 1/8" gap now (not finished nor painted yet) figuring it would close down to a little over 1/16" after paint.

[Electrogunner]

A multi tool blade with 180grit sand paper stuck on both sides made a perfect gap on mine.

[lr172]

Originally Posted by andrewtac

So 1/8 gap, and after paint it should be no less than 1/16 (assuming 0.015 paint depth).

.016 is 1/64" 1/16" is .063 You should expect that paint from both sides should reduce you gap by less than 1/32

2 coats of epoxy primer, base coat and 2 coats of clear should be under .010", depending upon who paints it.

[Vol88]

@Electrogunner, that sounds like a great idea. What worked best for you? Any pics?

[andrewtac]

Couple of lessons learned since this got tagged.

I got the doors hung to include the strut, but then gapped one door with the strut off (thankfully I started with one door at a time). Then I sanded the gap (I use a hotel key card with 40 grit, but start with 120 single side, then double it over, then got to 80, then double over 80, then 40 grit with the card, and finally 40 grit doubled over made for just about a 1/8" gap). I measure my gap with two tongue depressors glued together.

Then I decided to make the door even with the canopy (they were close but needed some glass work). So on one door I used some 1/8" door gasket in the gap, someone else on here had done it. I put the gasket on the lip, and put packing tape on it so the epoxy wouldn't stick, put the door on (without the strut installed, big mistake). I built up the areas that were low. After it dried, I got the door separated, reinstalled the strut, and it did not line up at all and the gap was way off. DON'T DO IT THIS WAY, better method below.

So since I was nearly starting over I decided to try a different method. First, everything needs to be on the door, to include the strut, all of the door mechanisms, etc. This is probably obvious to many, I should have know better. Next, I used packing tape to keep the doors from being epoxied together. I used sections of tape and overlaid one piece on top of another (sticky sides together, with about 1/3 of the sticky still exposed). Then I stuck the tape to the door sill, which resulted in none-sticky exposed above the door when the door was closed. Then I built up the low areas (and had to rebuild some of the gap, since it wasn't even). Once I was satisfied that my door canopy interface was level, I gapped the doors like I did before. Gapping was quick, maybe a couple hours; getting the surfaces level took a few build ups.

[lr172]

Originally Posted by andrewtac

Couple of lessons learned since this got tagged.

I got the doors hung to include the strut, but then gapped one door with the strut off (thankfully I started with one door at a time). Then I sanded the gap (I use a hotel key card with 40 grit, but start with 120 single side, then double it over, then got to 80, then double over 80, then 40 grit with the card, and finally 40 grit doubled over made for just about a 1/8" gap). I measure my gap with two tongue depressors glued together.

Then I decided to make the door even with the canopy (they were close but needed some glass work). So on one door I used some 1/8" door gasket in the gap, someone else on here had done it. I put the gasket on the lip, and put packing tape on it so the epoxy wouldn't stick, put the door on (without the strut installed, big mistake). I built up the areas that were low. After it dried, I got the door separated, reinstalled the strut, and it did not line up at all and the gap was way off. DON'T DO IT THIS WAY, better method below.

So since I was nearly starting over I decided to try a different method. First, everything needs to be on the door, to include the strut, all of the door mechanisms, etc. This is probably obvious to many, I should have know better. Next, I used packing tape to keep the doors from being epoxied together. I used sections of tape and overlaid one piece on top of another (sticky sides together, with about 1/3 of the sticky still exposed). Then I stuck the tape to the door sill, which resulted in none-sticky exposed above the door when the door was closed. Then I built up the low areas (and had to rebuild some of the gap, since it wasn't even). Once I was satisfied that my door canopy interface was level, I gapped the doors like I did before. Gapping was quick, maybe a couple hours; getting the surfaces level took a few build ups.

Some of this will depend upon how tight your door pin receptacles are. On my 10, the door pins are a close tolerance fit and they pull the door into a very specific position. I did my door gaps, after fitting the pins and without struts installed and they were identical once the struts were installed. I suspect in my case, it is the pins that are forcing to door into a very specific position, regardless of other forces, such as the struts. I had taken great care to ensure that the pin / retainer interface was round and snug.

Yes, the door is very much out of position as it closes with the strut installed, but once the pins are fully engaged, it pulls it back to center. My retaining blocks are also 2-3X the stock depth, plus a bevel (to keep the door edges from scraping the cabin top due to the strut pressure) and this may be a factor for me that is different

Larry

[andrewtac]

I am using the plane around and they are tight as well, along with the cam. Either way I'd at least check before making it permanent.