[R-390] Painting Knobs

[Barry]

Jacques,

I allowed the primer to dry overnight, painted the top coat, set it in the sun for a couple of hours to help the curing process, let it sit overnight, and then tried the scratch test.  I'm not so much concerned about the top coat being all that hard at that point but I am concerned that the primer doesn't want to stick to the metal.  I wouldn't think the primer needs heat curing to stick, would it?

Thanks,
Barry - N4BUQ

> Barry, IMHO, if you tried a "fingernail test" just few hours after the knob
> was painted, it is normal.
> Most paints can take a week or more to harden.
> The trick I used was to put mine under the summer sun once they were painted
> with the Krylon Dual-superbond, and they were "holding" such fingernail
> test.
> You can also use a small oven at 200F to promote the paint hardening.
> 
> 73, Jacques, VE2JFE in Montreal
> 
> Welp, I give up.  I tried priming one knob with a non-etching primer and a
> top coat.  I can take my fingernail and easily scratch the paint off down to
> the bare metal.  Sigh... Maybe I'll have them chrome plated.
> 
> Thanks,
> Barry - N4BUQ