Powdercoating

[Rick6a]

A couple of questions for those informed about powdercoating.

#1. The steel accessories on my truck that are factory powdercoated can be wiped with solvents without damaging the finish. Yet you can easily dissolve the "powdercoat" finish on the steel parts that are furnished with Van's kits if you aggressively wipe the surface down with MEK. Why?


#2. Can powdercoating be applied to a small part in two colors? Specifically, I would like to have the canopy handle on the RV-8 project painted to mimic the look of handles sometimes seen on military aircraft...a color combination of black and yellow striping. Is a two tone color combination possible using the powdercoating process?

[jmbaute]

I used to be a plant engineer for a compressor company and the powdercoat line was my responsibility (though I had no real qualifications for this). But, through the school of hard knocks I learned a couple of things:

One of the industry standard tests for coating durability is to take a 2 pound ball peen hammer and wrap it in MEK soaked rags. You then slide the hammer across the painted part and count how many strokes it takes to mess up the coating. The theory is that the hammer's weight is what is pushing on the surface of the part, and it takes the human out of the equation (guy X would push harder than guy Y).

We were usually able to get 20 or so rubs if I recall, before the coating would discolor. So, my point is, you should be able to expose it to some MEK but sooner or later you will mess up the coating. There are SO many variables in this process that it is difficult to say why Van's parts are different than the other guy. My first guesses are coating thickness, curing process, or the vendor of the paint.

We spent a lot of time to ensure proper surface preparation, powder application to get a consistent finish (one color only). The guy working in his garage probably does not have the resources for this or have a corporate quality engineer breathing down his neck.

Regarding multiple colors, it could be done by masking the part and putting it through the process twice. I'm not sure if this would be economical or not. Maybe just powder coat the high wear surfaces and spray paint the rest? There are probably several powder coat contractors in your nearest major city that you could contact.

Good Luck.

[JHines]

There is a company called Eastwood that specializes in refinishing and restoration supplies for cars.

They sell a "home" powdercoating system called "hotcoat". It has a small air-powered spray gun and you bake the powder on in a regular kitchen oven (from the junkyard). You can get small containers of different colored powders. I've never tried it myself, but it seems to get good reviews.

[az_gila]

Originally Posted by Rick6a

A couple of questions for those informed about powdercoating.

#1. The steel accessories on my truck that are factory powdercoated can be wiped with solvents without damaging the finish. Yet you can easily dissolve the "powdercoat" finish on the steel parts that are furnished with Van's kits if you aggressively wipe the surface down with MEK. Why?
......

Rick, I discovered a long time ago that powder coating is not all equal....
I had my motor mount powder coated in Los Angeles by a reputable company.
I discovered that it would wipe off with acetone...
I went back and checked, and they had powder coated it with an enamel type paint. They said I needed an epoxy paint, and stripped it and re-did it... it's now solvent proof...

Since "powder coating" only describes the application method, I think you have to be more specific and specify an epoxy (or urethane?) coating when you speak to the painters. Tell them the application... our application is similar to "under the hood" in automotive terms (i.e., solvent resistant).

gil in Tucson

[rv6ejguy]

Funny, I found when trying to strip my RV10 engine mount that the powder coating was like granite. I tried everything including sandblasting to remove it.

12 hours later using a razor scraper and Permatex gasket remover and sandpaper, I got it all off. I've never seen powder coating this tough before.