Chip Webber hotpop.com> writes: > Issues I can think of are: > -oxidation of copper. > -ease of solder of pre-tinned wires. > > Are there other issues? I can't remember having any problems before. I > can't even remember it being an inconvenience. The solderability of copper wire can be badly compromised by storage. You can still use it but it will have to be tinned (the ends) before use, probably using a tinning pot. Tinning in place (on a board) will likely lift of the copper patterns by the time the tinning took place. It all depends on whether the wire was stored properly. It likely was not if it is sold very cheaply. 'Proper' storage of bare copper to maintain solderability means plastic bag or container flushed with nitrogen afaik, or controlled environment. This does not keep indefinitely. On the other hand, if you would use the wire for crimping or punchdown purposes the issue would be moot (these methods remove the oxide from the copper wire). Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist