[jantar]

Epoxy primers are very resistant to automobile or aviation gas. How about other primers?
For empennage it does not matter match but for wings I keep wondering about potential gas leak and what it would do to primer?

Any thoughts or experience in this area?

Andrzej

 

[gmcjetpilot]

primer and gas

Not sure what you are asking. Are you thinking of flying in primer.

Primers are not necessarily good top coats. If you prime and fly, you will be contaminating it with grease, oils and fuels. You will need to rejuvenate the primed surface, at least requiring sanding off the outer surface and cleaning it well before painting. Depending on the level of contamination it may need to be stripped.

However I think a primed surface is better than bare fiberglass, which in the case of the cowl has lots of pin holes and can absorb some contaminate. As far as aluminum, if you are not going to paint before flying, I would not prime until ready to paint. Most primers are designed to be painted with in a very short time period after application. Some must be he shot with top coat in a few hours. The paint experts on the list can fill you in better.

George

 

[jcoloccia]

Epoxy primers are very resistant to automobile or aviation gas. How about other primers?
For empennage it does not matter match but for wings I keep wondering about potential gas leak and what it would do to primer?

Any thoughts or experience in this area?

Andrzej

No experience, but thoughts: stop worrying about it. If you have a leak, you need to get in there to fix it anyhow. If you notice the primer is munged up in the area of the leak, shoot it with your favorite rattle can after you've fixed the leak and cleaned the area.

 

[jantar]

The question I tried to ask was about the effects of gasoline on internal primer. Say you have a major splash of gasoline into the internal structure of the wings. Is SW988 going to wash out? What about Variprime or AFS? Any experience?

 

[Bob Axsom]

It's Probably not worth a lot of worry

If it's going to happen, it's going to happen and you will have to deal with it and move on. My whole bottom of the fuselage filled with 100LL after the first filling of the tanks and sitting overnight. It is a "quick build" with the "as delivered" primer and alclad. I drained the tanks, dried out the plane, cleaned up the LARGE pool of slow leaking fuel off of the hangar floor. Removed the tanks cleaned, dried and resealed (extensively) the access plates and started over. There was no detectable affect on the clear primer. I flew the plane for a year then had it painted after a slug of other problems that would have destroyed a paint job. Ten months later now the plane just keeps getting better as things are refined. The paint looks great on the outside and the interior looks like it did when I finished building it.

Bob Axsom

 

[Broken-wrench]

Painted fuel tank parts at united with Courtlands Fuel Reisitant Primer and they were awash with jet fuel. Didn't look like any of that paint came off. I talked it over with a Fellow Ua mechanic and were am not going to prime the inside of our fuel tanks though.