Paint/fin fillet troubles

[MissileDaughter]

I have an annoying problem...I orginally painted a small (about four inches tall) rocket a nasty neon pink a long while ago. I sanded most of it off after deciding that I did not like the color. The part that I could not sand was on the body tube near the fins and lunch lug. I dusted it off well (with a clean dry rag) and primmed it. I made sure that it was completely dried and then I painted it again (white). Had let it dry. Taped off the body tube to paint the fins. I took the tape off and the primer and paint came off with it! Infact, it started to peel.
I also have this fin on it that the fillet keeps cracking despite what I put over it to "heal it." I have used wood glue, white glue, vinyl spackling and as a last resort is to use a little more primer to cover it. It keeps on comming back.
I feel like throwing this one away and trying to build a different one.
Anyone have any ideas on how to correct these problems or any idea to what lead to these problems?

 

[Ryan S.]

your paint was not dry enough, another thing that would help would be to rough the surface up alot so the paint adheres and then lightly sand the first couple of coats to smooth out fussies

try some epoxy or CA on the crack

 

[wwattles]

Originally posted by Ryan S.
try some epoxy or CA on the crack

I second this idea. Get some thin (slow-cure, like 30-minute) epoxy and put just a little bit on the crack. Depending on the size of the crack, you might even be able to use a straight pin to help push some of the epoxy down into the crack. Slow-cure epoxy, as a thin liquid, will run down into the crack and form a very hard bond with the surfaces inside the crack, making a solid joint. The tube will fail before the joint/fillet does!

WW