Hi again. I just had encountered a problem. It involves my last build, the Fire Baby 2. I was just looking at it and noticed that on the wing to fuselage joint, both top and bottom, left and right are 'lifting'. Instead of being flat and flush as was during the build and finishing process, now looks like it has a radiused corner. i was wondering if anyone could possibly help diagnose this. A rundown of my build and finish:
All balsa joints glued with yellow carpenters glue.
Hinges incorporated crazy glue (2 drops per hinge, not affected).
2 coats unthinned Sig butyrate clear dried for a day or two (can't remember)
Sanded.
Applied 1 coat Sig butyrate clear thinned 50:50, dried for a bit.
Then, 1 coat Sig color thinned 50 : 50 then left to dry for a day or two.
Lastly 1 coat Minwax Polyurethane Clear.
Now here we are today.

So, again, any help, thoughts, ideas, or suggestions would be greatly appreciated. I am ready to start the next build,  but after seeing this, I would like to solve it first. I was really feeling that my choice of glue is the culprit.  Thank you.

Ok. So I got out of bed to check out the tail surfaces. The horizontal stab showed the same characteristics as the wing. Then I carefully cut off the peeling/lifting topcoat. No major damage, I will just coat the joints again tomorrow.  Thanks.

Yes it was Sig Supercoat clear and Sig color, buth thinned wiyh good automotive lacquer thinner.  As for fillets, nothing specific, as I had run a lite little bead of yellow carpenters glue along the joints as a fillet only.

  Never put dope over a water based glue before.  That could be your problem.  I don't think the dope will "bite" into very well. 

Chancey,
If you want to have square corners at the joints you will need to use a non shrink paint. Rustoleum will work but its not as light as the dope and you need to wait at lease two weeks before flying. If you want to use dope you need to add fillets. 1/4" around the wing and 1/8" on the stab and rudder. As was stated you need to use sig lite coat in the corners Brodak clear is low shrink. Thin all the dope 50/50 and apply in thin coats.

Best,   DennisT