Aluminum Hub Kits - corrosion?

[BuddyP]

Hey guys, have a set of Wilwood dynalite disc brakes with the alum. hub kit. Just curious what some of you have done to keep them from corroding? Or have you not had any issues with that? I have my hubs boxed up and ready to be sent out to get clear anodized.

[RobM]

i would think as long as you have them anodized they should be ok. maby using alittle anti seize on all the contact points would help.

[72SSAbody]

I have my hubs boxed up and ready to be sent out to get clear anodized.

STOP!!!

What type of anodizing are you having performed?

Aluminum is a great alloy to work with, BUT you have to understand how heat and cycles effect it's strength.

The correct type of anodizing to do on aluminum (especially one that is going to be heat cycled as well as cycled via forces in general) is called type 3 hard coating. This process does not involve elevated temperature baths. Type 1 and type 2 do...and that's where people screw up since hard coating is generally more expensive.

Joe

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The Chevelle Page (http://www.geocities.com/diels12000)

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[Matt@RFR]

Found with a brief search:

Type I anodizing bath nominal temp - 100ºF
Type II anodizing bath nominal temp - 68º-70ºF
Type III anodizing bath nominal temp - 40ºF

Annealing temperature range of heat treatable aluminum alloys (2xxx, 6xxx, and 7xxx series) - 650º-825ºF

[BuddyP]

Ok, kinda confused here then, Type 1 and 2 have higher heat cycles but Matt's post above notes 100 degree's for the hottest. That hardly sounds like it would affect a thing? Can you explain in more detail or is there another process that raises temp into the 300-400 degree range?

[Matt@RFR]

Nothing to be confused about. :) Most aluminum parts on military aircraft are anodized. Don't worry about it.

Don't worry about what type you need, either. Take your parts to your friendly local anodizer, tell him what you are doing, and he'll discuss it with you.

The only thing you really need to worry about is what color you want, how long you want it to last under what conditions, and if you have several parts you want anodized, it's best to take them all in at the same time, because as batches of parts go through their chemicals, the dies get weaker until they top them off again. Same batch = same color.

[BuddyP]

Thanks! Just wanted to do clear anodized. Nothing radical. Just so they wont' corrode and look like ass in the future LOL!

[Matt@RFR]

Buddy, try to find out what alloy the hubs are. They will probably be one of the following: 2024, 6061, or 7075. Anodizing takes to different alloys differently. Some alloys with the same clear will turn yellow or a brownish gold.

[BuddyP]

It's whatever Wilwood uses, I would assume 6061... none the less, from my anodizing knowledge, the brownish gold would be from leaving it in too long. I do know that's how they get anywhere from clear to tan to bronze to black is just how long it's left in there during the process. I'll ask the guy and see what he says though.