Ben:

As to 1) really small pre-fluxed but untinned wires can be used to  remove the solder after it is inserted into the cup and heated. Capillary action will remove gold. Also solder wick can be used but off the top of my head I don't know how small it is available.  2) double-tinning just means technician adds solder to completely fill the cup. Then remove the solder via wire or solder wick. Repeat process second time. Then you are ready to fill the solder cup with solder (a third time) for final soldering operations to solder wire to cup. 

Hope this clarifies. 

Gregg Owens

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Gumpert, Ben
Sent: Friday, May 03, 2013 8:31 AM
To: [log in to unmask]
Subject: [TN] How to Tin (remove gold from) Solder cups

Technetters,

It looks like from the archives that we all agree that removing the gold from solder cups is necessary to get a good joint. So that leaves me with a couple of questions:

1. Does anyone have some recommendations on a good method to ensure adequate gold removal, especially on really small cups? Is adding solder and then removing it with a solder wick the standard method?

2. What does a double-tinning method really mean (i.e. what do I need to do to meet the requirement of J-STD-001E Para. 4.5.1?)

A single tinning process would be to fill the cup with solder wire and then reflow that solder to 'tin' the cup, followed by the installation of a wire. So does a double tinning just mean that the solder is removed ONCE and the cup tinned a second time with the solder that will be used to create the final joint? I have had some people tell me that the solder had to be removed TWICE to be considered 'double-tinning'. (Of course the main goal should be to get rid of the gold and the process should be based on achieving that goal, but that may be a different discussion.)

Ben

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