Sorry guys, a little off topic but I thought some fellow car guys could help with a presentation model I am working on for a client. If I have a carbon steel casting that is polished unidirectionally with med grit sandpaper, is there a chemical way to dull or lightly grey the metal without getting rid of the sanded finish and without signifigantly rusting it? The goal is to make it look like it was polished 10 years ago, not the day before yeasterday. Obviously bead blasting would remove the sanded finish.

How about alittle Easy Off oven cleaner on a rag and wipe it down till you get the desired finish color. I have heard in the past that this stuff will dull metal finish. Please test this out on a non visible area first. Just a suggestion and dont hold me to it if it does not do what you want. Just trying to help you out.

Would ooo steel wool be best for a uniform look, as chemicals can leave spots. I realize chemical would be easier to just dunk in but if its relatively flat surfaces shouldn't be too bad. If you do go chemical, be sure to agitate with a stiff nylon brush for uniformity.

Sand blast or vapor blast will take the shine off.

Thanks I'll give that a whirl. It doesnt matter what it does, I can re polish the metal if I mess up. I had thought of diluted acid in the past, but never alkali.

dip in a muriatic acid solution "get it from a brick supply house" then when you are satisfied with the "patina" nutralize the acid with a bakeing soda water solution...

I second the acid suggestion. It should give you the grey cast you are looking for without altering the texture. Start with a dilute solution and add more acid if needed. Don't forget to wear gloves and eye protection. Also, always add acid to water, never water to acid.

Tom

Try the least invasive method first. Try a kitchen scrub pad first, it may be enough. Then add the BonAmi to the pad to get more abrasion if needed.

Wheel cleaner will dull it some.