Combined anodize & powdercoat

[seanc]

This is a dual forum post, combining anodizing w/powder coating. I’ll be posting on the PC forum as well. Now that I’ve got these two figured out, it’s time to do some real parts.

I’ve got a cast aluminum part that has a steel part embedded. I’m planning to mask the steel (w/Caswell liquid Mask-It), anodize the aluminum, then mask the aluminum, and powder coat the steel. (or the other way around).

Will the anodized & dyed surface withstand the 350-400º oven bake for 15 minutes?

or would it be better to powdercoat the steel & mask it before anodizing?

Does anyone see other problems with this?

Thanks, Sean

[dogmeat]

as far as I know, anodizing (as long as you let the whole part dry thoroughly) can withstand a much higher temperature than the 350-400 degree range.

[neilfj]

Anodizing will handle the heat without a problem. As suggested, I'd let the anodized part dry at least a week before subjecting it to the heat. The sealing process does not seal the anodized cell 100%. It takes a little time for the sealing plug to complete its formation. I don't know what would happen if you subject a freshly anodized surface to 350-400F temperature during this period. Perhaps someone will respond that has personal experience, but failing that, waiting a week wouldn't hurt.

[Fibergeek]

The problem you may face with heat is the different thermal expansion between metallic aluminum (expands a lot) and the ceramic anodize (expands a little). This can produce a substantial mechanical stress on the anodize and crack it. I don't know the temperature where this becomes a problem. NeoMoses thinks its around 300 deg. F..

[seanc]

Thanks guys!

Concensus from both forums is to anodize first, then powder coat.

I’m still waiting for delivery of misc. aluminum fasteners to tie the pieces together, but I’ll post the results when done.

[seanc]

Fibergeek:

Just missed your post as I was submitting the other one.

I recall reading a while back something about a 300º limit, but can’t find that web page again. It must have been in regard to the expansion issue.

I think I’ll take one of my earlier test pieces, partially PC it, then bake it and see what happens.

Thanks for the heads up!