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Rusting powdercoat

PaulvS

PaulvS

Well Known Member
My RV-6A finishing kit from 2000 has been stored inside my shop during a very slow build. Most parts are still OK however the canopy frame and roll bar were not covered over and there is filliform type corrosion on the surfaces where dust settled. My bad, I guess, for not keeping covered, as I thought powdercoat was impervious. As an aside, I was never really happy with the factory powdercoating on the frame because there was marker pen lettering showing through and baked into the coating.
Now I think I need to take it all back to bare metal and refinish, in either new powdercoat or epoxy.
I've tried sanding the coating and it comes off gradually. Is there an easier or better way to get it off?

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Powdercoat

I too have an early kit. Some of my HS hinges were like that. I media blasted them bare, then did AKZO. For the VS, I just used maroon scotch Brite pads, as I plan on painting the entire area when the time comes. I noticed some powder coat chipped off when the rivet expanded, so I touched the bare metal with epoxy primer on a brush. .The media I used was some plastic media that wasn't really aggressive. .probably would have been better (and quicker) with glass beads or sand blasting, as it would leave a prepared surface for the primer to bite into.
 
Hydrochloric Acid

Parts are soaked in hydrochloric acid to remove powder coat, works in minutes, neutralize in water, paint or re powder coat, like new.
 
I believe any shop that does powdercoat can remove the old coating prior to refinishing, at a cost, of course.
 
At the risk of starting another Prime War:

I intend to remove the powder coat from the top of my new stick so that the Infinity Grip fits. I may even have to reduce the diameter of the stick a little.

I'd like to just prime the bare steel. I don't expect to do a lot of steel priming so I'm wondering what would be a simple, effective way to do this.

Rattle can zinc chromate?

Thanks!
 
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My impression is that the original prep for the powder coat was insufficient.

Had a shop two doors down from a Powder Coating business.

Jerry was a great guy. Every stage of his "personal tour" witnessed him stressing maintaining cleanliness of the part to be coated.

FWIW
 
You can remove powder coating like any other paint. Mechanically, or with paint stripper.
For priming, you can use whatever primer of your choice. I wanted a different color for my roll bar and canopy frame and just scuffed it up and primed with P60G because that?s what I had hanging around. Most consider P60G for aluminum but it works great on steel although I prefer epoxy on bare metal.

For the stick, just mask off and use a commercial paint stripper. It comes off easily.
 
Hydrochloric Acid

AlexPeterson said:
"Honey, really, it won't hurt the bathtub to fill it full of acid, just don't step in"...
Click to expand...


Very good friend has a powder coat shop, he placed my 2005 era unused grey engine mount in his vat, 15 minutes later it was shiny bare metal, 30 minutes later it was the new vans white, I was there less than an hour for the whole process, he said for bigger items that won't fit in the vat he sprayed them while hanging with the acid and kept them wet for several minutes till the coat started falling off.
 
JonJay said:
You can remove powder coating like any other paint. Mechanically, or with paint stripper.
For priming, you can use whatever primer of your choice. I wanted a different color for my roll bar and canopy frame and just scuffed it up and primed with P60G because that?s what I had hanging around. Most consider P60G for aluminum but it works great on steel although I prefer epoxy on bare metal.

For the stick, just mask off and use a commercial paint stripper. It comes off easily.
Click to expand...

I have had zero success with paint strippers on powder coat. I tried several brands.
 
How about?

Personally I have been giving all the powder coat parts a light scuff with scotch Brite and shoot 2k epoxy primer over it... anything wrong with that? I make a point to use a different color scotch Brite on all steel parts to ensure I never use them on aluminum parts...
 
AlexPeterson said:
"Honey, really, it won't hurt the bathtub to fill it full of acid, just don't step in"...
Click to expand...

you might want to watch Breaking Bad before you try that. There is this one scene .....


You can also soften up powder coat with a plumbers torch. There is a video somewhere - perhaps EAA hints for homebuilders - where somebody does this on a part that has to be welded.
 
Update

Thanks everyone for the suggestions, not sure about hydrochloric acid in the bath though...:confused:

I tried some paint stripper and it works very well to the powdercoat off quickly and easily, with much less effort than sanding. The coating scraped off after being covered with the gel for about 3 minutes. The brand I tried is Poly Paint Stripper from the hardware store and the active ingredient is Dichloromethane.
 
Chemically stripping powder coat...

PaulvS said:
... The brand I tried is Poly Paint Stripper from the hardware store and the active ingredient is Dichloromethane.
Click to expand...


Dichloromethane = Methylene Chloride

It looks like strippers containing methylene chloride have all but been banned in the US.

Has anyone had good results chemically stripping powder coat with any of the non-methylene-chloride strippers currently available?
 
Powder coat

The shop can do it. A good shop will treat prior to powder coat. I don't remember what they use.
I ordered all my canopy weldments bare so I could have them powder coated to match the interior.
 
wirejock said:
The shop can do it. A good shop will treat prior to powder coat. I don't remember what they use.
I ordered all my canopy weldments bare so I could have them powder coated to match the interior.
Click to expand...

What some do is burn off the powder coat using high temps.
 
no sub

Dad's RV-10 said:
Dichloromethane = Methylene Chloride

It looks like strippers containing methylene chloride have all but been banned in the US.

Has anyone had good results chemically stripping powder coat with any of the non-methylene-chloride strippers currently available?
Click to expand...

I haven't. My experience is that if it does not have Methylene Chloride it is not paint stripper, no matter what the label says.

The link describes two sad Darwin events which deprives 340 million others of its proper use.
 
"Parts are soaked in hydrochloric acid to remove powder coat, works in minutes"

I spent 34 years in the coatings removal business: I never saw any paint or powder coating that could be removed by emersion in hydrochloric acid. Do not try it!

Besides not removing the paint; emersion in hydrochloric will cause hydrogen embrittlement of the part, requiring baking in an oven to push the hydrogen out of the surface of the steel.

Media blasting or methylene chloride based paint stripper is the appropriate method of removal here.
 
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