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Old 21st Jul 2019, 11:45 am   #5
The Philpott
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Join Date: Aug 2016
Location: Colchester, Essex, UK.
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Default Re: Using Lead free solder.

As per Jon's comments durability is fine as long as the majority of the modern solder is removed first. The story as told to me is that a very small %age of Pb in a finished joint is OK, as is your normal 30% or 40%. Somewhere in between these %ages however, is a dead zone where the joint is unsatisfactory and the Pb can even crystallise out of the alloy.

The magical world of metallurgy- I still can't quite cope with Pb and Sn having medium melting points, and Pb/Sn alloys having a low melting point..

A Pb/Sn solder with 1 or 2% of Cu is said to preserve the soldering iron tip for longer, but the melting point does shift upwards more than you expect, so perhaps not for soldering delicate components.

Dave
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