I'm at my wits end! All I can do is scream!  I have been working on the wing to fuse fillets on a Smoothie for the last two (2) months and I'm loosing the battle. I applied a nice epoxy filler material to make a 1/2 inch radius on the wing root fillet about two months ago. I have been spray panting the airplane with a thinned covering of white AeroGloss dope. PROBLEM!!!!  Everytime the dope dries, it shrinks and pulls away from the fillet. I have sanded and primed the fillet a dozen or more times. I have sanded down to the bare filler and started again at least 3 times. The dopes still shrinks and pulls away from the fillet. I added a drop a caster oil per ounce of dope to keep the dope from shrinking so much. No improvement! Every time the dope drys it shrinks away from the fillet. I slice the fillet with a knife, fill with thin CA and sand and paint again. Same results!

Does anyone out there have a suggestion?  HELP; PLEASE!   

Tom W.

Randy,
I thin about 50-50. The Aerogloss is aready thin compared to SIG dope. I used Super Fil (made by Poly Fiber, in Texas) two part epoxy to make the fillet. Super Fil is very lite and easy to work with. I've used it on other planes. The temperature in my basement is between 65 and 70 and the humidity is about 60%. I haven't used retarder. I used the caster oil to add elasticity to the dope so that it wouldn't shrink so much. I don't know what else I can do. I would have had this plane finished a long time ago if it wasn't for this damn fillet problem. 

Bill smith os right about putting a barrier down before using dope. I usually use Sigment or Ambroid or Duco cement and a lot of times I never dope the fillet but go directly to the primer and use that to fill and finish the fillet.
Dennis