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Color anodizing of machined aluminum with carbon steel bearing races pressed in -situ

I have found a good anodiser local to me who are willing to treat a small batch of exotic cycle components. Several items have steel race pressed in place. Before I annoy the anodiser with stupid questions is it possible to mask the steel components? I understand that the moment the parts are lowered into the tank the steel will start to dissolve.

Ian W Burgess
Cycle Restorer - Manchester, England
2005

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2005

Damn near impossible for a pressed in component as it will trap solutions between the steel part wall and the aluminum wall and will leach out later yielding an ugly part.
Plug the hole, anodize, remove plug and extremely carefully press the steel part in. Pressure can fracture the anodize.
Lots of trial and error.

James Watts
- Navarre, Florida

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Perhaps I should re-phrase the question more carefully. The pressed in races are hidden cosmetically, would it be possible to seal the race surfaces and seal the edge of the pressing?
Is it indeed posssible to mask or seal non-aluminium components against the sulfuric acid?

Ian W Burgess
- Manchester, England
2005

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2005

Ian,
It is not difficult to seal 99% of the part from the acid and other chemicals. The problem is sealing the area of the interface of the aluminum-steel. If you can mask about 1/8" onto the aluminum and are very careful, it can be masked well enough to survive the acid. A tiny boo boo can ruin the part. Sooner or later, you will loose at least one part.
I would use a good quality of lead tape and then use a paintable maskant over that for the best probability of having it work. You might be able to use a thick aluminum tape and burnish the edges very well and then use a paintable mask.

James Watts
- Navarre, Florida

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