How to get auto touchup paint to stick effectively?

I am having trouble getting paint to stick to bare metal when a patch of bad paint has been sanded smooth to expose the steel - even though I clean carefully and apply primer. Is there a 'primer for the primer'?How to get auto touchup paint to stick effectively?
You should use use a wax remover (suggest PPG DX 330) and then use a metal etching primer. Sand with 400 grit wet or dry paper. Wipe again with the wax remover and finish the touch-up. All areas you paint must be properly preped and masked.How to get auto touchup paint to stick effectively?
if U putting paint onto bare metal, U will need an etching primer, make sure the area is dry, clean, oil and grease free. use a fine wet and dry sand paper on the area to to smooth it off, and to key the surface





i hope this helps
Do you have trouble getting the primer to stick to the metal or the paint to stick to the primer? If primer to metal, get some grease, tar, and wax remover and wipe the metal and let it dry before priming. Anything on the metal will interfere with the primer to metal bond. If paint to primer, apply paint to primer between 5-10 minutes after you've stopped applying the primer. If you wait until the primer dries, you will have to lightly sand the primer before the paint will stick to it. Read your primer and paint cans for re coat instructions.