mill finish prep

[blewis999]

I need to do industrial black ano with no finish requirements. What I mean is I will be anodizing half inch square bars with threaded holes.

The bars need no polishing/blasting/ or sanding. They just need to be black.

Can I just degrease - WB test - DE-oxidize then anodize?

Every one the fourm seems to be having GREAT results with parts that are pre-treated to some degree. I am very impressed with the level of sofistication in here.

I hope to be able to contribute myself after some time.

Thanks

[acidrain]

Yep... that's pretty much it. You can skip the de-ox too if they are freshly machined parts (de-ox will dull it just a bit).

[blewis999]

thanks for the response.

I am not sure, do you realize the bars are not machined on sides. they are half inch squares, cut to length, then drilled.

So i don't have to remove the ink printed on the side either?

[acidrain]

I would de-grease/remove ink with lacquer thinner, blow dry, then go to the SP degreaser to pass water break, then de-ox, then ano normally.
That may sound kind of wierd, but if there is any grease or oil, you don't want that going into the de-ox.

[blewis999]

Thanks Acidrain. Hopfully I will be trying this out today.

[M_D]

Etching the parts in a sodium hydroxide (lye) solution after the degrease/cleaner and before the de-ox step may be beneficial in giving a more even and consistent color and appearance. Mill finished aluminum can vary greatly in the oxide layer which will be present, and in my opinion a sodium hydroxide etch is vastly superior to a sulfuric/ferric acid based de-ox solution in removing aluminum oxide.

[blewis999]

thanks M_D. That sounds alot simpler and less handwork. I would assume etching the parts would sorta ensure WB will pass.

Would you agree?

I will search the fourms for a starting point of mixture for the lye.

[acidrain]

Yes, I agree... etch step will ensure a uniform surface.
So... lacquer thinner to remove ink/grease/oil, etch, de-smut/de-ox, ano.
No need to de-grease after de-smut as long as the parts are not handled with bare hands, and they pass WB.
Etch solution: 1 can (16oz?) Red Devil lye into 3gal water (no more than 70F).

[blewis999]

Thanks. I will post results when I get this all sorted out