Anodized finish is bad... unavoidable or result of shortcut?

[patdh1028]

Hello all,

I recently got a part in from a reputable machine shop my company does a lot of business with. They had sent out a part to be anodized and the finish looks pretty awful. The shop owner called me up to tell me that it wasn't really anyone's fault (but mine, I suppose) because the part, which was only out for modification, had been anodized once previously (when it was made) so the second layer didn't turn out well.

I'm having a tough time buying that. We've had parts twice-anodized before and they looked fine; it looks to me like the anodizers cut corners.

See photo: What do you think?

 

[swall]

It looks like the anodizer's cleaning step of the process was faulty as it did not remove finger prints. You could have them strip and re-anodize. And not handle the parts with bare fingers!

 

[btrueblood]

Get out your Jr. detective kit, and go take fingerprints of the employees at the different vendors.

Seriously, that fingerprint mark is evidence of poor cleaning and/or poor handling at some stage of the anodizing process.

 

[tomwalz]

Amen.

Pure sloppy work in the cleaning.

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[IRstuff]

But was the fingerprint really from the second vendor and not the first? And was it really just a recent fingerprint, as opposed to one that had sat there for a while, letting the acids in the residue to slightly etch into the surface?

TTFN
faq731-376