Letter 15008

How to Avoid sealing blooms

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Can anybody help me on how to avoid sealing blooms which occur after hot acetate sealing. We do small parts which are Anodised followed by black electrocolouring and then sealed. We want solutions to avoid sealing blooms as then it is very time consuming to to buff them to remove them.

Any help is appreciated.

Best Regards

Archana Gholkar
ACPL - UK

Hey, Calcium Acetate is a white powder, a so are 12 other compounds that may form in your line, either in the seal or due to what happened up stream. I will send you or any other reader a copy of my two page list of causes of white spots or white smears. First look up stream for calcium and/or zinc both of which form white colored compounds with oxalates, citrates, acetates, fluorides, glyconates, metasilicates, carbonates, sulfates, et al.

Robert H Probert Robert H Probert Technical Services Garner, North Carolina Editor's note:        Mr. Probert is the    author of Aluminum How-To / Aluminio El Como

There are commercially available additives that prevent "bloom" or "smut". In addition, filtering your sealing bath with a 5 micron filter will also help.

Guy Lester
- Ontario, CA, USA

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