Warbird Information Exchange

I know there are folks out there doing this every day, so I figure someone can give me a pointer or two...

I'm frustrated with my corrosion control efforts on some steel parts for a Champ (err..L-16, for this forum) I'm restoring. What I've tried is to bead blast, then conversion coat, then prime, but by the time I'm ready to prime a few hours after the conversion coating, a thin layer of rust has formed.

Either that layer of rust is the conversion coating or I'm doing something wrong.

So, I'd appreciate any input on what's wrong with my approach.

Should I go straight from the bead blaster to the spray booth and skip the conversion coating?

Thanks in advance,

Kyle

Send it out for Cadmium plating before painting.

Probably a factor of where you live. I have some steel parts in my garage I beadblasted clean 12 years ago & they still look like I did it yesterday...

You could use this stuff straight from the blasting cabinet....

http://www.semproducts.com/Catalog.asp?prod=164

It will turn the steel black & the coating is fine for painting over. It's basically the same as OsPho.

PPG also has a version but I forget it's name/designation.. altho there is some out in the garage..

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Kyle, what are you using for a conversion coating on your steel parts?

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Rob C

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– Michael Crichton

Could it be that what you think is rust, is actually the yellow tinge from phosphoric acid in the conversion coating?

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Those who possess real knowledge are rare.

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Rob, I'm using a phosphoric acid etch, followed by a phosphoric acid based metal conditioner (DX-520) by PPG.



Don't think so - the color of the thin film is rust brown.

Maybe something to do with the acid etch. Not sure why you need both the etch & the DX. I've used the Dx stuff on car body panels & left the parts out in the pissing rain without them rusting for a week or more before now.

Why not just beadblast, laquer thinner wipe down & prime them with epoxy ?

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Those who possess real knowledge are rare.

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The few who possess real knowledge and can set it into motion of their own hands are the rarest of all.

you are not going to get a better surface to hold primer than a fresh sandblasted surface, as has been said, blast, wipe, paint, done

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Matt Gunsch, A&P, IA, Warbird maint and restorations
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There is a coating, not sure if it's some sort of mineral oil or what, but lots of guys who build bare metal 'rat rods' wipe it on the bare steel body of their cars and it keeps the body from rusting. And I understand if you decide to paint, it will wipe off with mineral spirits. Check with your local hot rod shop or big time auto paint & finish store. If it works on a driven '30 Model "A" hot rod, it should work for you-

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Boiled linseed oil.