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Ask the Experts

August 31, 2011 - Updated
August 28, 2011 - Originally Posted

Re-qualifying Cored Wire Solder

Is there a process for re-qualifying cored wire solder that has passed the expiration date?

P. G.

Expert Panel Responses

Always a tricky one, in theory there is nothing in the solder wire that can go off so the expiration date could be just a logistic function. How ever depending on the field you are working in it could be possible to see if it is still useable, in some industries you will have to abide by the use by date. If you can use material then a quick easy test is to see how it solders to a flat copper strip or coupon. Make sure the copper is clear of oxide by using a mild acid wash or abrasive clean. The wash in alcohol to make sure it is clean and free of oils. Put a known weight or length of the wire screwed up into a ball on the copper and heat it up. This is best done on a solder bath (float and a static part of a wave solder machine) or hot plate, but any controlled heating method will do. If the solder spreads out giving a uniform and relatively flat silver circle then the wire is probably OK. If it form a lump or ball then it is probably not so good

Richard Boyle
Global Product Champion, Henkel Electronics

Richard Boyle is a Global Product Champion at Henkel Electronics. He has over 25 years experience in the electronics assembly industry and is responsible for the global technical service of all of Henkel's solder materials.

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