No passwords, no registration, no paywalls, no popups, no AI

As an Amazon Associate & eBay Partner we earn from affil links

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

Search our quarter-million Q&As

Home of the finishing HOTLINE since 1989

-----

Copper plated aluminum sand casting gets brown dots

Q. we are doing Zincating, bright nickel, acid copper on aluminium sand cast decorative items. We face brown dots after 2 or 3 days after spray lacquering. Our process sequence after copper plating: rinse, sulfur 15% concentration, 2 rinses, tamarind water for removing sulfur, then again rinse, anti-tarnish, then lacquering, our components are having some small pin holes due to sand casted.

61145-1b 61145-1a

I attach photocopy. Please help

vasanth karunakaran
- Chennai India
August 17, 2020

Please check your zincating process and let us explore more.

Prof. Karthikeyan Sambantham
- Vellore TAMILNADU India
August 22, 2020

Nadcap Chemical Processing Auditor - PRI, traveling
Process Engineer / Chemist - Denver Metal Finishing, Colorado

Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.

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: