Powdercoating fun

Mattstrike

Random Crazy Custom Car guy
Feb 13, 2014
542
1,139
Just started out doing my own powdercoating, figured I'd have to do some on my current project car:

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I haven't really messed around or tried anything special to get the powder to work with plastic valve covers yet. I have the eastwood dual voltage kit for the gun, so not really a professional setup that I can really ramp the voltage up, but I had problems getting the powder to stick to the plastic. Tried pre-heat, which helped enough to get the powder on, but ended up that 400f was too much for the plastic covers and they started bubbling slightly anyway. Maybe 350f might have worked, but the powder I have was a wrinkle finish and needs a specific cure temperature/ramp up to work right (even that took some trial and error to get it right). So I ended up with Camaro aluminum covers for this round.

But people here that have had plastic valve covers coated - do you know what temp they were cured at? My next project that I want to do some coating with doesn't have the option to replace the valve covers with aluminum.
 

Mattstrike

Random Crazy Custom Car guy
Feb 13, 2014
542
1,139
I sourced powder from prismatic powders, I am not aware if they have the option of getting a different formulation of a specific color. I was aware that those low temp powders were out there, just not where or how to get them, and if I can even get a color/texture match to something I'd already had.

I was hoping the valve covers were *close enough* that I could get away with a standard cure temp powder for that reason.
 

cap42

Restoration Hell
Mar 22, 2005
2,764
2,430
Bolingbrook IL
I did PC out of my garage for a number of years, in order to do plastics and other non magnetic materials you have the part heated to around 200-250 degrees pre heat. Do a large dust coat to get full and even coverage and then cure it at a lower temp for a longer period. The lower temp is defined by the powder as well as the melting point of the part.

So say a valve cover that is plastic will melt at 375 but that is the cure point of your powder (@ 20 mins) you would do your cure temp around 325 for 45 mins.

There was a large internet argument on what what curing at those temps and times did to the integrity of the part. However there was nothing fully conclusive as to it being true or false just a lot of speculation.
 

cap42

Restoration Hell
Mar 22, 2005
2,764
2,430
Bolingbrook IL
I sourced powder from prismatic powders, I am not aware if they have the option of getting a different formulation of a specific color. I was aware that those low temp powders were out there, just not where or how to get them, and if I can even get a color/texture match to something I'd already had.

I was hoping the valve covers were *close enough* that I could get away with a standard cure temp powder for that reason.

I'm pretty sure prismatic had low temp cure powders years ago, the low temp powders are ideal for plastics but back a few years ago they didn't have a full range of colors textures available in low temp so people were making due with the regular cure powders.
 

Frank Dukes

TCG Elite Member
May 5, 2009
4,528
6
Rockfordia
As far as what the chemists here would say, the cure temp is important to reach for full hardness of the paint. Failure to reach full temp can fail impact test. This is mostly a CYA thing for large customers in my experience. Pre heating the part is good. Also there are primers available to help the powder stick to the plastic parts.
 
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