What material did you use for the fillets?

I have heard that some of the duplicolor primer is enamel based. Is there any chance that your can is enamel? that would certainly cause the problem you are describing.

This is true. 

Plus, I never spray primer directly on the fillets, either.  I try to get as little paint as possible on the fillets.  All lacquers shrink anyway.

I can't say much about the Epoxilite, though since it's been at least 20 years since I used any......... I just never did like the stuff.  Switched to regular epoxy and microballons as soon as I first saw them.  Been using the stuff (of course I cannot remember the name! LOL!! ) from Aircraft Spruce for the last couple years.

The stuff we are talking about is a big all gray spray can which has filler/primer on the front.
It is also available in quarts.

I have shot every imaginable type pf paint over that stuff with no issues at all, so it surprised me when you said you had a problem.  I have even used it several times as a *sealer coat* to keep stuff under it from being affected by a new top coat material. 

REspectfully, with intent to educate not prove anyone wrong. Laquer is an interesting material. when you spray a coat of laquer, a large portion of the solvent does not evaporate immediatlyl, it actually makes its way from the new coat down into the previous coats all the way to  the substrate. when it reachs that, then it reverses direction and evaporates out. Or it continues through the substrate in this case balsa and can evacuate the other side I imagine. I know that on cars, sheetmetal and filler, laquer will dry much faster over sheetmetal than over layers of built up primer because the solvent is absorbed less by the underlying layers. NOw that being said, if this is in fact enamel primer, its apparantly staying tight enough to survive partially. However over the fillets what could be happening is that there is no layers of material under it to absorb the solvent so itis bubbling the surface. where there are other layers of laquer under the primer, it wil  absorb a portion of the solvent allowing a slower evaporation and less likely hood for bubblling to occur. The physical reason that material bubbles is because it has dryed and established its "finished dimension" IOW it has decided how much space it will occupy so to speak. then when you introduce solvent as in laquer into the dryed volume of enamel, it does not reflow like laquer does, it cannot vary its volume to accomodate the influx of solvent and in trying to it swells underneath causign surface tension to get very high causing the paint layer to flex and swell, poof bubbles.
Hope this explains a bit.
of course this is all theoreticall because we arent there watching it happen but it sure sounds like laquer over enamel.

Since the Duplicolor can is not what you guys are using, I'm guessing it is enamel primer. But now that its down, I have to deal with it. There is no way to get it all off. So any suggestions on the best way to spray over it. I've been more or less dusting clear 50/50 dope over it. So far not too many bad areas. I'd like to shoot the white base now. Should I just spray one good coat of color and see what happens?

By the way, I feel like a total idiot about this.

IMHO, your best bet if you insist upon continuing with what you have is to build everything up with thin layers. They have to go on wet enough for adhesion, but without stacking a ton of solvents on it. As you build up some film thickness you should see a reduced sensitivity. Make sure you give PLENTY of time between coats. Do you have a complete covering of the primer on the airframe or is it just filling low spots? One of the things you will notice is that the edges will be much more sensitive to lifting, the film is thinner there and so the solvents attack it more. Not to mention that the solvent creeps under the edge and softens the lacquer underneath it.

Bill L, I have read tons about fillet problems so I understand. I really didn't gather that he was having problems stricktly with the fillets, but due to the nature of the lacquer enamel reaction, It would also be the most likely place to have a problem of this nature, incidently, I believe the cause of the fillet dilemma is the  same thing, no where for the solvents to go and it breaks down the bond allowing the shrinking action inherant in the lacquer to "pop" the finish off the epoxy.

Well, I'm going after it with the sandpaper today. I know I can't get it all off, but I sure can get it out of the fillet areas and anywhere else that it's thick. If need be, I'll shoot more primer on (the correct stuff this time) and re-block it. This is going to delay me a few days, but I'd rather the finish not peel off in flight. This sucks.
I should'a just painted it with Rustoleum.

Another idea is to recoat with Polycrylic, for a buffer layer. You'll need to scuff the substrate and again scuff the Polycrylic (for "tooth"), but it should "insulate" the enamel from the lacquer. The bad news is that it doesn't smell good, or at all, actually.  Steve