Harbor Freight(hush hush, i know) Iron Armor Filler Primer doesn't seem to adhere too well to metal?

So I have an old car with some rust spots and I bought some filler primer to try to fix those spots up and I'm not sure what exactly is happening. The can says that it's dry to the touch in 15mins, wet sandable in 30mins, and cures in 6hrs.This is my first time trying to do any touch up work on a car and I'm very confused about if I'm doing it right or not. I know that prior to putting paint down, I'm supposed to clean the metal with acetone(or something else solventy like that?) but the closest thing I had was goof off which seemed to do the job very well, However, I noticed that it started dissolving the primer. I assume it won't do this when it cures but I'll only find that out tomorrow morning.The other thing that I noticed happening which I also was somewhat concerned about was tape ripping off primer which should've theoretically been dry. I had accidentally sprayed onto some rubber and plastic and I assumed that because the tape I was using (some crappy offbrand painter tape)barely held onto the panels and was over all not very sticky, it wouldn't hurt to put it on the primer. I needed to do so because I had already found out that goof off dissolves primer(that isn't cured atleast?) However upon peeling up, the primer that was on bare metal had peeled up but the primer that was layered on top of old primer and paint had stayed on.For the second issue, I just chalked it up to poor prep work so I wiped off any primer that would come off and applied some more after again cleaning the surface with goof off so hopefully tomorrow I'll see how well it turned out. Any suggestions? via /r/cars http://ift.tt/2szP13w