No cost, no registration, no passwords -- just aloha, fun & authoritative answers
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Where the
world gathers for metal finishing
Q&As since 1989

-----

Copper/solder cleaning

Hi All: First of all, GREAT SITE! To the matter at hand: I have a questions regarding cleaning of a copper heat sink with 60/40 tin lead soldered copper fins. The current process involves alkaline soak, reverse clean with a brief reverse at the end, room temp 10% sulfuric acid. The solder becomes discolored, and adhesion of e/n is poor. Is there a better cleaning method? To solve the problem, a copper strike is applied. Thanks in advance! Chris

Chris Ford
- Lowell, Massachusetts
1999

Chris, I think what is happening is the sulfuric acid is reacting with the lead in the solder and forming an insoluble lead sulfide. Try using a dilute hydrochloric acid (10-30%) instead. You could also consider using one of several comercially available alkaline E-nickel strikes prior to your build-up plate. This would help minimize contamination of your plating solution.

Keith Wicklund, CEF-SE
avionics - Minneapolis, Minnesota
1999

(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: