Electronics Forum | Wed Sep 03 11:42:21 EDT 2008 | robinj
If the tarnish is really dark, it is very difficult to remove. Since it is yellowish it is only in the early stages. Replating will definitely work. I have used sulfuric acid based cleaners to remove this yellowish color. But rinse well and dry quick
Electronics Forum | Sat Apr 24 10:43:31 EDT 2010 | davef
Hege: Sounds like this customer is a putz. Ask the putz to sign a release, acknowledging responsibility. Here's a couple more links on imm silver: * http://www.pcbdesignschool.com/wp-content/uploads/2009/08/the-study-measurement-and-prevention-of-t
Electronics Forum | Fri Aug 22 10:01:52 EDT 2008 | robinj
I have seen this problem before. If the color is yellow usually it is caused by moisture left on the boards from poor drying after immersion silver. One of the ways to get rid of this is by dipping in acid cleaner solution. If the board supplier uses
Electronics Forum | Thu Apr 27 10:35:21 EDT 2000 | Russ
Scott, I am a little confused, when you mention "silver thru hole vs. plated through hole what do you mean. A silver "immersion" type finish vs. HASL (Tin lead)on your PCB? Or are you talking about using silver solder to perform intrusive reflow of
Electronics Forum | Sat Aug 23 08:43:32 EDT 2008 | davef
Ugh, there are more reasons that immersion silver [IAg] to go yellowish than pigs at the county fair. That aside, sulphur is one of the reasons, as you say. The sulphur can be from a variety of sources, such as: * Pollution in the air * Ill advised p
Electronics Forum | Tue Sep 02 16:07:04 EDT 2008 | blnorman
Colorization is relatively uniform across the board. "Processing" is first pass reflow. I belive MacDermid is the ImmAg supplier. Plating thickness has not been determined, our XRF is being revitalized. Elemental analysis did show a large copper
Electronics Forum | Tue Sep 02 22:08:34 EDT 2008 | davef
MacDermid Sterling seems to take-on a brownish tint in high dew points. Look at figure 3, p14 here: http://www.enthone.com/docs/CircuiTreeNov2006ImAgStudy.pdf We not so sure that it's fatal. That you see Cu makes us nervous. Since your XRF is doin
Electronics Forum | Tue Jul 25 10:04:22 EDT 2006 | russ
There reasoning is ignorance. They are most likely concerned about tarnish on PCB surface. We have let immersion silver PCBs sit out open for 10 days in a noncontrolled enviromnent. We had no issues with these assemblies and they were segregated a
Electronics Forum | Sat Aug 30 11:42:49 EDT 2008 | davef
Some immersion silver [IAg] products can go brown with aging. On a newly plated board, we expect you to see Ag, C, & O. The amount will vary according to supplier and thickness. Questions are: * How uniform is the brown coloration of the IAg on the
Electronics Forum | Thu Mar 06 11:48:09 EST 2008 | muse95
Black pad with IAg??? Tarnish is NOT black pad. Tarnish is usually just some silver sulfide on the surface and can also usually be soldered through, by using a little additional, or slightly more agressive, flux, and still make a good quality solder
