plating, anodizing, & finishing Q&As since 1989
Specification for sealed Hardcoat Anodizing
September 7, 2010
I have a question about Hardcoat Anodizing. We calling out for Hardcoat Anodize and using ASTM B580 [affil. link] Type A Black According to the standard it is not sealed unless otherwise specified if I specify Sealed a how do I and What do I get?Rich Stalter
Product Designer - Exeter, Pennsylvania
Usually hard coat anodize is not sealed, because the sealing process softens the hard coat and it doesn't wear as well.
- Savannah, Georgia, USA
Most job jobs will seal a dyed coating (type 3, or type 2) in a solution containing nickel acetate. As long as the seal is of good quality, you'll get a dyed coating that won't fade in a short period of time when exposed to light, and also won't be prone to staining by fingerprints, or liquids that these parts may come in contact with.
anodizer - Boise, Idaho
If it is dyed, then it MUST be sealed, so say "sealed".
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
September 27, 2010
The fact that one is asking for dyed hardcoat implies that a seal, such as nickel acetate, is therein specified. That's always been my interpretation and I've yet to be challenged arguing this approach. The only customer that insisted "BLACK HARDCOAT NO SEAL" on a NASA job called me a week after delivery complaining about black dye oozing out when they cleaned the part. Luckily I had explained the likelihood of this happening before we processed the parts. We've since done more work for this customer but all the parts are no sealed.
Milt Stevenson, Jr.
Syracuse, New York