On Sat, 1 May 2004, Andrew Grebneff wrote:

> Depends on what the tubes are made from. Silica glasses are soluble
> in "ordinary" (impure) water; I'm not sure about pure water in this
> case.

High power tubes aren't usually glass.  Usually they're metal-cased.

In the transmitters he's talking about, it's common for the water to flow
in direct contact with the anode connection, since the anode (aka. plate)
is the part of the tube that dissipates the most heat.  Since the anode is
at several thousand volts, the water has to be pretty pure indeed to keep
the leakage current down.

David Brodbeck, N8SRE
'86 Volvo 240DL wagon
'82 VW Vanagon Westfalia Diesel