Overbake and second coats...

[Guest]

So I'm still confused about doing two different colors, I've never done it before and I'll be attempting it next week so I want to get ready.

How do I shoot two colors when one or both are not overbake stable?

For example, a valve cover with letters in mirror red and the rest in mirror black. How do I do this?

Do I coat the letters first, full cure, then shoot the rest mirror black, then full cure again? If so, how does this affect the mirror red? Do I only do a partial cure on the red?

On a related subject, what's the best way to accomplish this two tones as far as taping goes? Just patiently tape off the letters or is there another way?

Thanks again everyone!

[Guest]

Re: Overbake and second coats...

If I was worried about over baking I would shoot one or the other first and only bake till the powder flows out. Then pull the part and let it cool down. Now mask for your next color then bake till flow out again. Once again let the part cool down so you can unmask then put your part in the oven to cure. This way both will cure at the same time and you won't have to worry about overbake.

Your best bet is to patiently mask off the letters, this is how I do it anyway.


Harley

[Auto-Cycle PC]

Re: Overbake and second coats...

Which red are you going to use because I have never had overbake problems with reds?

I would coat the entire cover red and fully cure, mask the letters and coat it black place it back in the oven until flowout remove the masking and fully cure the black at a little lower temperature for longer.

Mirror orange is the only color I have ever had real problems with overbake, and it turned yellow in spots.

[Guest]

Re: Overbake and second coats...

I was under the impression that any mirror color cannot withstand overbake. Can most of them take it?

I guess the question goes back to powder coating basics and my lack of curing knowledge. There must be a reason why these powders have a time limit on the curing time. If the red is meant to cure for say... 15 minutes, and the black for another 15 minutes. Wouldn't curing the red for a total of 30 minutes have some sort of negative impact on it?

Thanks again for all the advice.

[Guest]

Re: Overbake and second coats...

Sorry guess I wasn't much help. I don't want you to have any problems. AutoCycle and Harleydad are real experienced, so I would go with what they suggest.
I am kind of confused though on the mirror powder overbaking though. Once it's cured you can rebake and you're okay is that it?
Harley

[Guest]

Re: Overbake and second coats...

Also get yourself some foam brushes to take the powder off where you dont want it for second coats. Make the foam brush a tiny bit damp so the powder sticks to it.