Dave,
I doubt you need to worry about tin whiskers as a hobbyist... not due to the solder or to tin plated traces or parts. I consider the lower ability to "wet" the connection and higher required temperature for RoHS solder to be the larger drawbacks to using it.
73 de Jim, KB3PU
Received from Dave at 10/29/2020 14:55 UTC:
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Jim,
I read about tin whiskers a long time ago but didn't much worry about them as I wasn't making pcb's etc then. I just read about them before you brought them up. I came to the conclusion that the "tin" was the problem and not the solder. After seen some microscopic images it looks pretty wild and plenty of room for disaster. In fact, I bought some Tinning solution but only used it once. I also bought the crystals but never used them. Now I have quickly advanced (with my most basic and useless projects) to getting my boards made. I am waiting for my first order to arrive hopefully next week. :) Then after I really any mistakes or things I should have done different, I will have learned something so it's all good.
On 10/28/2020 12:19 PM, Jim Higgins wrote:
RoHS isn't a requirement that applies to consumers, incl hobbyists who might tinker with the product. It applies only to manufacturers. We - hobbyists - can repair even brand new RoHS compliant gear using tin-lead solder if we want to.
RoHS is an EU thing dating from early 2003 that expanded industry wide because industry wants to do business with the EU. I have no idea how the low/no-lead portion of it was ever incorporated into products made for applications in space... since the problem of "tin whiskers" (Google it) in pure (or almost pure) tin solder was documented back when vacuum tubes were king and solid state didn't exist - in the early part of the 20th century.
We (the USA) have had at least one satellite failure and one nuclear plant malfunction due to tin whiskers. In the case of a satellite - even a big expensive commsat as was the case - it's not really convenient to go up there to fix a connection that's growing a whisker that has caused a short circuit even if the short hasn't caused permanent damage. RoHS solder formulation has improved since those days and conformal coating over completed boards takes care of any remaining risk. Conformal coatings in consumer products make repairs much more difficult.
Jim H
