I used the battery and leads to a bare board to show the effects of handling contamination.

Works about the same as the other methods

Using a bare board without solder mask and tin/lead reflowed circuits I:

1. Connected a battery to two circuits using a 9 volt and alligator clips, the board had gold tabs I clipped onto

2. Then placed a single drop of DI water onto the exposed trace

3. Had the operators and inspectors look at a magnified view of this [placed all this under our Mantis]

4. Then...as they were watching this happen, well actually nothing was happening at the time, I asked them to very lightly touch the drop of water with the tip of their finger...........wow........the activity in that little drop was amazing.

5. Then I explained to them the contaminates, oils, etc from just their fingertip acted as the catalyst to this reaction they witnessed.

This drove home the importance of proper handling of bare boards to avoid contamination.

Franklin