On Thursday, June 18, 2015 at 1:53:09 PM UTC-4, Phil Hobbs wrote:
On 06/18/2015 10:16 AM, wrote:
I've had old copper wires (In some old insulation.. zip cord type stuff)
and it gets and oxide/ coating/ something/ that flux doesn't attack very well.

I end up having to first scrap it with sand paper or a green scrubbie.
(Scotch brite) and then tin it.

I've always wondered what the tenacious oxide is.

George H.

I don't know. It seems to be some sort of organic crud iirc.

I'm not sure if you're talking about the same stuff, but the organic crud
I've encountered on old wires I've interpreted as being plasticizer from the PVC insulation -- the same sort of stuff that coats the insides of car windshields
in the summer.


--
Norman Yarvin http://yarchive.net/blog