Paint cast iron after Evapo-rust

[GNP]

Can you paint over the gray film left over from Evapo-rust, or does it need to be removed first? I have a set of cast iron wheel weights, on a 41 yr. old garden tractor, that need de-rusting.

[enjuneer]

I always either sandblast or wire brush the surface to remove the gray layer, then wipe down with a solvent before painting. Aerosol brake cleaner works well.

[Martin S.]

Listen to Bob, he's a master at doing this.

[Rick_B]

enjuneer said:

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I always either sandblast or wire brush the surface to remove the gray layer, then wipe down with a solvent before painting. Aerosol brake cleaner works well.

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+1 - I've used this process on hundreds of pieces of cast iron with no problems.

[blackhat]

Is this a restoration or a " it's too ugly to be seen using" project?

[GNP]

blackhat said:

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Is this a restoration or a " it's too ugly to be seen using" project?

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I got new rear wheels, and didn't want to put the weights back on all rusty. Didnt know if paint would stick to the gray film. I'm still mowing with the tractor.

[blackhat]

Don't think I'd bother with the Evaporust for that. Wire brush on a drill and a couple coats of Tremclad.

[pprobus]

After looking at ER's website to refresh my memory, it appears all you need to do is rinse with water and then you should be ready to paint. I took the additional step, when I was painting some rusted ATV wheels of also, per the directions on the primer I was using, of wiping them down with mineral spirits and let them dry and then primed them. I highly recommend using a self-etching primer prior to whatever paint you use, the SE quality should eat through that gray layer, which should still be good metal.

Good luck,
Paul

[Mike Brady]

Self-etching primer. That's a new one on me. Is that available in rattle cans?

[pprobus]

Yes. Rustoleum makes one, Dupli-Color makes one and it has been widely used in the automotive repainting industry for many years. I have found Rustoleum's in Lowes and I think in HD as well. I was planning on using Dupli-Color's wheel paint, but could not find their SE primer, locally, so I ended up doing a bit of research and found that both Dupli-Color and Rustoleum used lacquer SE primers, so I figured "lacquer is lacquer" and that the formulas couldn't be that much different, but to be sure, I used primer-sealer after I was done with priming the wheels (after the SE primer, I used Rustoleum's sandable primer which has filler in it to fill in low spots) I used Dupli-Color's primer-sealer to avoid or at least minimize any incompatibilities between the topcoat and primers, then sprayed Dupli-Color's wheel paint as the topcoat.

Self-etching primer is for use with completely bare metal and I think fiberglass as well, although you could mask off areas with old paint and use it to prime the bare metal part. The etching action of the primer helps it "grip" onto the metal to make it adhere better.

If you need some assistance finding it in the store, Rustoleum classifies their SE primer as an "automotive" primer. I don't know about nowadays, but in the '90's and well into the 2000's, SE primer was the go-to primer for car repair/customizing shops. The autobody repair manual I have, although a bit dated (Autobody Repair Technology, printed in 2009), it still has the use of SE primers as the first priming step on bare metals. The book is about the best resource I have found on metal painting, unfortunately there is no equivalent book, that I am aware of, for metal finishes as Bob Flexnor's book on wood finishes.

Paul