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Lacquering or clearcoating of Anodising
Q. Hi
I am looking for help/products to seal Black/Hard Black anodising with a lacquer. I have a customer who wants to remove machine marks by way of vapour blasting and then have a glossy finish after having them anodised. Any information on processes or products would be greatly appreciated.
Plating Shop Manager - Banbury, Oxfordshire, England
November 19, 2010
A. Hi, Dave.
You should be able to apply nearly any clearcoat to hard anodized aluminum. However, it would seem that you lose most of the benefits of the hard anodizing process if you do so.
Why not polish, electropolish, and/or chemically bright dip the aluminum, then do conventional anodizing, black dye, and seal. You would need to balance the anodizing thickness between too thin for good saturation of black dye, and too thick for the desired glossiness.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 22, 2010
Q. Hi Ted
I have pointed out to our customer as you say the point of having their parts anodised hard seems to be lost if a lacquer coat is applied after, however the parts in question are married against plastic parts and they want the anodised parts to look more like the plastic parts! They have seen similar camera parts from Germany and want me to replicate them if possible. I however know very little about Clearcoat lacquers for this purpose. Is it possible to dip/spray the finished anodised parts and then stove them?
- Banbury, Oxon, United Kingdom
November 23, 2010
A. Hi Dave. The dipping/spraying is no problem but the "stoving" might be. It may crack the anodized layer, which has a much lower coefficient of expansion than aluminum. But whether this will cause an appearance problem under the lacquer I don't know.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2015
Product to sealclearcoat hard anodizing?
Klasse Glaze
on
Amazon
(affil links)
Q. Hello Finishing.com, does anyone have experience with a particular product (i.e. Klasse sealant glaze, ceramic glazings, etc.) that a hard anodized surface could benefit from?
Mainly looking to prevent color fade, shed water, extra protection from elements, etc., as these are brake calipers that are factory hard anodized. I know the HA surface is very durable but it's still not completely impervious to wear and tear.
Hobbyist - Half Moon Bay, California USA
April 4, 2020
A. Hi Jason. We changed your wording from "seal" to "clearcoat" because the word "seal" has a universally used & accepted meaning to anodizers and we don't want to muddy the water :-)
A lacquer or clearcoat is not going to perform like hard anodizing, but if you are speaking of the visible non-wear surfaces, yes, you can apply a clear coat of your choice if you wish. We can't suggest specific brands or sources (why?), but readers are certainly welcome to comment on recommended types. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 2020
Q. Hi there.
I have some hard anodised alloy bicycle components, which were damaged by abrasion from the road surface in a fall. I have sanded out the damage with fine grit water paper, but this has of course compromised the anodizing on that section. Is it possible to cover the now un-anodised section with clear lacquer to protect from corrosion and possibly get a somewhat closer match with the anodised finish.
Regards
Al
- Auckland, New Zealand
May 27, 2020
⇦ (tip: readers rarely show interest in abstract questions, but people's actual situations usually prompt responses) 
Q. Hello, Dave!
Wondering if lacquer, applied over anodizing would adhere to the surface well and have good longevity in decorative metals application.
- Carlstadt, New Jersey
November 7, 2020
A. Hi Tracey. Dave's posting was from 10 years ago, so someone else will probably have to step in to answer your question.
It isn't clear whether you are from a finishing shop and have control over the anodizing operation, or whether you are someone who must start with what you can buy, such as , for example, a craft jewelry designer.
If you can anodize but not seal the aluminum you have a better likelihood of good adhesion, but then why anodize instead of chromate conversion coating which sounds less expensive and better? Getting good adhesion on sealed aluminum usually requires an etching primer, and I don't know of any that are clear, although they may be some.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2020
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