Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

finishing.com -- The Home Page of the Finishing Industry

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

Light Fast Test for Checking Black Anodising

I recently had a huge problem with black anodising turning purple which turned out to be a sealing or "lack" of it issue. As a result I would like to be able to test the parts quickly and have heard there is a light fast test using nitric acid that can be carried out quickly. I have also heard there is a standard test of light fastness using UV light. I would appreciate any help that you can share!

David McKinney
- Northern Ireland
2005

I'm not familiar with a UV test for sealing. However, a very simple test (to check for seal quality) for dyed anodized parts, is to place a drop or 2 of 40% (vol) nitric acid on the anodized surface for 2 minutes. After rinsing, if there is a white spot, or noticeable discoloration where the acid was, that usually means the parts werent sealed properly.

Marc Green
anodizer - Boise, Idaho
2005

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: