I've been working on my new JCR bumper, but I'm having some doubts on the primer. Please help me out with some simple advice. Its been humid here in GA, so that may be affecting my work. So I did rustoleum all products, scuffed it up with 220 paper so I could see lines all over, wiped with mineral spirits, and sprayed as directed on the cans. I did self etching primer, let it sit 12 hours then did auto primer on top. After 8 hours after the primer I can still take my fingernail and nick it down to the metal. it is not tacky but it nicks easily, is this normal? Should I just let it set for a few days and see if it hardens. I want to apply the rustoleum bedliner on this, so I went ahead and did a very small patch, one scuffed up again with a "scotch pad" which by the way just scuffed and did not strip it, and one just on the finished primer, and regardless I think I must wait a few days to see how hard it is. Any advice on if this is screwed and I just need to sand it back off or what corrections to make?

 

Mineral Spirits is probably leaving a film not allowing the primer to adhere. Use a wax and grease remover, you can get it from a autobody supply shop. It will remove everything and not leave a residue. You can follow it up with metal prep and then the primer. The primer should stick really well.

 

The primary problem is the product being used, in addition to the cleaning process. In the cuurent weather (rain, humidity), it will take a long time to cure - best thing would be to clean it with a non-oily solvent, like acetone, or lacquer thinner, prime it and place it in the sun to "cook" for a day or so and it will cure to a point ready for top-coat.

I prefer 2-part direct to metal (DTM) epoxy primer, which you can get through Amazon, or at a local O'Reilly Autoparts - BUT, it is not cheap, like the rattle can, or other 1-part products, plus you will need an air compressor, respirator, paint gun(s) and additional solvents for thinning, cleaning, etc. The 2-part products use a chemical reaction to cure the coating, instead of "drying" naturally - and will ultimately be a better finish, but at a cost.

Give it some time to cure - then top-coat, and plan more time for that to cure.

 

I used self etching primer then regular primer over. Waited about 2 hours till dry to the touch. Then covered with paint and I can't take it off with a hammer! Seems like the primer is just weak stuff. but this is my first time too so who knows

 

Since you seem the closest to my situation, how long did you let it all cure?

 

Whats frustrating about this is the directions on the various cans of product I used did suggest mineral spirits, and I did wipe it dry...I do understand about the wax and grease remover being a better choice as I read various input now. Will wait some more time, that is likely going to improve my situation...hope i don't have to sand it all off. I'm not in a hole with that much money but time is money so....

 

Since I spray painted my whole motorcycle with good results I can tell you this: Timing is everything!

Usually when you prime, you need to topcoat within a certain time frame (prob < 1 hour) or wait several days for it to cure. If you wait to long but not long enough, you will end up with a poor paint job and may get orange peel or paint that doesn't stick.

If it looks crappy (orange peel/foggy/scaly), your timing wasn't good.

If the paint peels up on its own and flakes off without you doing anything, then you prep work wasn't very good and you should clean the surface better before applying paint.

Since you used all rustoleum products, the paints should work together and not fight each other. I doubt you needed two primers, but since you did, you may have needed more dry time before topcoating.

Also, even though the can says "dry to the touch in x and cured in y" or whatever, it could take up to a week to fully harden and give you maximum strength.

I used High Temp Rustoleum for my bike frame, and two days after the paint job I could still leave marks with my fingernail and whatever I used to move the frame around. 7 days later, it was hard as a rock, then I could touch up the spots I screwed up. I'm in atlanta, so I can attest to the awful humidity causing sh!t to not work as it should.

 

Did it this weekend and got rain that night, Greenville sc, so close. It was over cast. I used two cans of primer would wait about 30 min between coats, dry to touch. Then two cans of rustolem hammered. The primer was I guess dusty but after paint the coating is Rock solid. The paint takes a lot longer to dry! Messed up and rolled over to early cardboard stuck and took a while to remove. Rain set in so need a final coat but base coat I can't even scratch to primer with a key!

 

Probably 4 hours total time cleaning masking and painting.

 

Ok things are going much better now with some dry air and afternoon head the primer paint has clearly hardened. Test patches of bedliner inside the bumper are solid. Applied 2 coats of rustoleum bedliner to the bumper now, looking good, no runs, perfect texture. Need 3 days to cure.

JG out