Metal valve puzzle?

[GeorgSc]

Whether it was done to create metallising on valves, or metallic paint, was used, is still open....

... but the ubiquity of true metal receiving valves is still open!

Are You kidding?
Georg

[Lee de Forest]

Originally Posted by Lee de Forest

Extract from the virtual valve museum plus strip down of metal valve
http://www.r-type.org/static/6j5.htm
"A few years ago a special detector valve was issued by a British valve maker, in which the entire valve was enclosed by an additional envelope to reduce the effect on a valve when the speaker was placed too close to it.

I always understood that it was very satisfactory and the only disadvantage was the size. This idea of course is fundamentally the same as a metal-coated valve."

I think what the valve museum were saying was that there was a valve with a metal envelope around it which worked like the metal sprayed coating. I don't think that this envolope was like the American all metal steel cases but more like the one shown in the second to first post.
http://www.r-type.org/static/met-coat.htm