The authoritative public forum
  for Metal Finishing since 1989
-----

Is surface conductivity grounds for rejection of anodizing

We have a customer who is testing our anodizing by using a conductivity meter. Their claim is that if there is conductivity, then the part has no anodizing. In this particular case the flat plate shows coverage, (no conductivity), on the flat surface but the edges, (lasered), show conductivity. Are they correct in their rejection of the parts as having no coating on the edge of the plates? Visually the parts look fine.

Fred Hood
supplier - Eugene, OR
November 5, 2009

---

First of two simultaneous responses -- November 6, 2009

Fred

Anodize builds up perpendicular to the surface. If the laser cut edge has a minimal radius, and the anodize is thin, it is quite possible to have the condition you describe.

Refer to Table III in section 6.10.3 of MIL-A-8625F for guidance.

Willie Alexander
- Colorado Springs, Colorado

---

Second of two simultaneous responses --

The laser cut edge has a remelt or slag area that is not anodizing. They are correct, but you can ask for an anodizeable part, which you are not getting.

James Watts
- Navarre, Florida
November 6, 2009