-- The Home Page of the Finishing Industry

on this site
current topics

World's most popular finishing site / Internet's friendliest corner

topic 0958

Soldering problems with bright Tin Plate

A discussion started in 1998 but continuing through 2018


Q. We're having trouble soldering brass parts plated with electro-tin plate, bright. Is the "bright" finish part of the problem? What is the best finish to call out? Thanks!

J. Willis
- - MDS


Modern Solder Technology
from Abe Books


A. Dull Tin (no organics added) remains solderable longer, but fingerprints badly, so it depends.

Other possibilities: The bright tin bath may need a carbon treatment, or your pre-plate cycle may not be leaving a clean base metal. Do you strike first with cyanide copper ? Are you etching the brass before plating? I was going to write "over-etching", but you should not etch at all, the brass should stay bright in the pre-plate cleaning step, the cleaners could be too hot, the acid could be too concentrated.

tom pullizzi monitor
Tom Pullizzi
Falls Township, Pennsylvania 


A. You may try analyzing the tin plate bath for Copper, Zinc, Iron, etc. contamination. These contaminants are usually detrimental if over 500-1000 PPM.

good luck,


Dave Kinghorn
Dave Kinghorn
Chemical Engineer
SUNNYvale, California


A. How long between plating and soldering? If parts have been on the shelf for an extended period, especially if at elevated temperature or for more than six months, or if there is no barrier plate between brass and tin, zinc and/or copper diffusion can poison the tin. This usually shows as a dark discoloration of the tin deposit, but might also affect solderability. If freshly plated, ignore this line of reasoning.

bill vins
Bill Vins
microwave & cable assemblies - Mesa (what a place-a), Arizona 


Solder Joint Technology
from Abe Books


Another problem you may have is conversion of the metal tin plating to intermetallic. If the plating is mostly intermetallic, solderability is greatly diminished.

Intermetallic conversion is a time and temperature dependent process. Has the material been plated for a long time, i.e. many months? Have the parts been through any elevated temperature processing after plating? Either of these factors will contribute to formation of intermetallics in the plating. Intermetallic formation can be prevented in most cases by a nickel flash between the copper or brass and the tin.

larry hanke
Larry Hanke
Minneapolis, Minnesota

September 6, 2018 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I have an issue that after tin plating on brass with copper layer on it soldering is not happening. What can be the reason over it.

Poshendra Mahant

September 2018

A. Hi Poshendra. We appended your inquiry to one of several threads about this problem. Note Tom's suggestion that bright tin is more difficult to solder than alkaline tin, and Larry's that intermetallics may have formed in storage.

Please search the site for "solder problem tin plated brass" to get some additional understanding of the possible causes for this problem, then get back to us with the details of your situation. Thanks!


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Striving to live Aloha

Q, A, or Comment on THIS thread SEARCH for Threads about ... My Topic Not Found: Start NEW Thread

Disclaimer: It's not possible to 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 may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental Compliance

©1995-2019, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.