View Full Version : Advice Needed: Powder Coat or Single Stage Urethane


07-16-2011, 11:25 PM
So I am getting ready to detail my engine bay and want to get some opinions after bead blasting to either powder coat or to just spray a single stage urethane with an epoxy primer for my engine bay inside fender panel wells. These will have a 60% gloss either way.

Now I have been told if I go the powder coat route the surface will stay cleaner and in turn when cleaning is needed will clean-up much more easily and stay that way compared to just spray painting these panels with urethane?

I have also been told that if I shoot a nice single stage urethane with a flattening agent to achieve a 60% gloss, I will have to "color sand" the urethane after spraying to get a nice closed surface comparable to that of a powder coated surface? - I am told one must color sand the urethane then polish it to get a comparable tight powder coat like surface finish.

However it seems to me that with the painted urethane surface, the maintenance would then be a constant to keep it clean with a 60% flattening agent mixed in.

Any thoughts?

Bob K
07-16-2011, 11:47 PM
Iím just curious. How do you plan to heat up the powder coat to melting temperature? Do you have some sort of giant oven or are you just coating small panels and then putting something together when they are cooked?

Sorry I canít help much on your question because I donít do powder coating so I donít know how the results compare. As for flattened clear, you tend to destroy the effect if you polish it. I do use flattening agent and also pre-flattened clear but I never found a necessity to buff either one. Clear or single stage are not porous, so you do not need to do anything to ďtighten upĒ the surface. Am I misunderstanding your question?

Bob K

07-17-2011, 12:27 AM
Hello Bob. No your spot on with my question.

I have not worked with powder coated parts much in the past and do not have that time tested feel that I have with sprayed surfaces. Regarding the powder coating, I would take the parts down to get them powder coated from my local automotive powder coater that I know. Expensive though.

With my spray set-up I could spray my parts and put them back on like I have always done and it has worked. But someone I know had all his front engine bay shroud work done in powder coat. When asked why he went to the expense he replied that the surfaces far easier to clean and stayed cleaner longer and did not collect dirt like a traditional painted surface did. Now all my engine bays have been sprayed using just plain enamels in the past as I do resto work and want to keep the look as original as possible. This time I am considering going the powder coated route IF that is, I can get the finish I need, which is not too glassy and it is true that the cleanup is superior. But considering costs, with that I thought perhaps shooting a single stage urethane could do the trick as urethanes tend to have that clean surface tension look that is very similar to a powder coated surface.

So this is what I am hanking over.

BTW: I never shoot clears on any of my 50's resto and museum work. Just does not belong there and if I venture into the powder coating, this would have to be tweeked to get an acceptable finish.

Bob K
07-17-2011, 02:36 AM
Iíve got an idea you could try. Clear coat a painted panel and then go over it with a Trazact Clear Coat Sanding Disk wet powered by a short throw sander as if you are getting it ready to buff. Then just stop there. You may get the look you want. I found this by sanding a run out of some flat clear I was spraying. I couldnít tell where I had sanded and where I hadnít sanded. It all looked the same. I donít know how dirt will stick to the sanded area so maybe a test would tell you that. My project was on wood furniture that will never be outside, but it may be a cheaper way to get the look youíre after.

Bob K

07-17-2011, 06:51 AM
If I were doing the job I'd probably add a "gloss reducing additive" to the paint. I usually measure the amount of the GRA and spray a test panel to make sure I get the amount of gloss I want.

07-21-2011, 01:06 AM
Yes HOC (House of Color) sells a flattening agent by the quart. They have directions on how much to add to get a certain % of flat starting with a standard gloss like with their gloss black urethane. I have both on my shelf but have not ventured there as of yet. I was going to when I got sidetracked by the possibility of powder coating the panels. Kinda like the idea of "take em off, drop em off then put em back on" concept. I like the possibilities of this idea IF a final finish could be perfected. Just thought I would ask the community here about their thoughts and experiences regarding this venture.