David, what are you using to clean your spraygun?  You should just be using lacquer thinner.
Alan

When I read your post, I thought you might have a compatibility issue between brands of dope.  But, you said the Brodak color dope, over Sig dope, was fine.  No problems.  Your problem appeared after the final clear coats with Brodak clear, correct?  And, how long has it been "staying sticky?"

Incompatibility evidence, from what I was told by those more experienced and adept at painting, would be almost immediate but maybe in your case it took more time for the two products to mix and cause your problem.

I also wonder if you might have mixed up the thinners.  Although some have used Brodak or Randolph thinner with Sig dope, I never took that chance.  After testing Sig clear over Brodak on scrap pieces, I have used Sig clear for the final clear over Brodak or Randolph colors , but I used the Sig thinner.

Sig dope and Brodak dope have very different odors.  That does not mean one can't be used over the other but I would not take the chance unless I tried it out on some scrap test pieces to be sure.

You have nothing to lose by trying Dan's suggestion but even if it finally dries as it should, I wonder about the durability of the finish.


 

David, what are you using to clean your spraygun?  You should just be using lacquer thinner.
Alan

I was using a hardware store product called Cleaner of some sort. I discovered that it turned dope to a gluey jelly. I am worried that I may have left some in the bottom of the spray can. I will not be using it anymore.

But I vote for all products to be compatible with all other products. Maybe I lost the election.

I've used Acetone to clean gun but I prefer lacquer thinner.

I'm not sure of the cause yet, incompatibility of some kind. Hopefully just with that stuff called cleaner.

Fixes: I tried the dish soap and sanded it with 1500. Tried direct sun. Then went on a house painter site and they suggested rubbing it with Mineral spirits. Tried a couple little sample areas (not that I had anything to lose at this point). And after one hour it seems it may have made a 70% improvement. It's my daughter's plane, and my polyspan dope experiment plane, so if it maintains the 70% improvement, I think I'll go with that. Perhaps with a second application I can get a 90% improvement.

Thanks for the ideas.

David