[Amps] Transformer varnish removal

[peter.chadwick at Zarlink.Com]

Rich said:

> Tomcat spray also works well for pre-paint etching of aluminum

Soemwhat easier and more controllable is caustic soda (sodium hydroxide).
Readily available (or at least was - I wouldn't bet on it still being so
with the modern environmental police) for drain cleaning - I believe a
proprietary name in the US is 'Drano'.

On some alloys, it leaves a blackish shading: a dilute nitric acid dip gets
rid of that, but somewhat easier is to use a cloth well soaked in vinegar.

The exercise is best done in a well ventilated place because hydrogen is
given off.

73

Peter G3RZP