Yet another test for cleanliness:

Put a drop of the 0.1N Silver Nitrate solution often used for titrating in
labs on to the Copper.

If the surface is dirty, the Copper turns black slowly, unevenly, and the
black will rub off.

If the surface is clean the Copper turns black INSTANTLY, evenly, and will
not rub off (except with a pencil eraser).

It is a judgement call, (no numbers, drives ISO people bonkers!) but a real
good test.

Rudy Sedlak
RD Chemical Company

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################