Is there any way to prevent those pesky blisters from forming in the fillets?

I just cut a slit through one on my new Victory and am about to start the repair. As I was cutting I kept thinking that this is something that ought not happen.
I've seen a lot of posts about fixing them but nothing about preventing them. DOES THIS MEAN BLISTERS CAN'T BE PREVENTED?

I used SIG silkspan to cover the plane and butyraterate dope to seal the wood and stick the tissue down.
1/2 hour epoxy and micro balloons make the fillets.
Rattle can "dupli-color" primer. Brodak dope the rest of the way to the top.

Where did I go wrong? 
Just look at this picture...........If I wasn't bald already I'd be ripping out my hair!!

I use epoxolite and/or aeropoxy and have never had a fillet bubble. Sand the fillets after they have had a day or so to cure, clean with prepsol to remove any left over resin or junk, use a brush to applyn one coat of Brodak primer and let dry for at least a day. Sand the primer and they are ready to paint. Follow Roberts advice from here and you should never have another fillet problem.

I'll certainly stay away from the fillets in the future. In the meantime my plane is popping up blisters almost as fast as I can fix them.

Since I like my pasta with olive oil & garlic  , the only way I can avoid fillet blisters when using dope finish is to buy a big box of surgical gloves and use them when handling the unfinished plane.
  Never, never, ever lay a bare finger on the fillets once installed. As tempting as it is to fondle the woodwork, my skin doesn't touch the plane until after paint.  I also give a quick swipe with the Sherwin Williams version of Prepsol to the fillets before shooting, and as said by others here, never shoot directly at the fillet area.

Since I've gone to the Klasskote epoxy paints  this is no longer an issue though I still use the gloves just for habit's sake and to keep the chemicals off me when I'm painting.

EricV