[R-390] Re: IERC tube shields and tube temps...a field expedient...

[Kenneth G. Gordon]

I have had pretty good luck with simply spray painting the 
inside and outside of a shiny tube shield with flat black paint 
after masking off the lower part which would make electrical 
contact with the grounding ring on the socket. My idea was that 
the shiny interior of the tube shield was reflecting some of the 
heat back into the tube, and by painting it black, some of that  
reflected heat was absorbed instead by the shield and 
transferred to the outside.

Temperatures were noticeably lower for tubes with which I 
tried this, although I didn't actually measure them. 

I have not yet tried to cut ventilation slots in them.

I suppose I should try some sort of heatsink material around the 
outside where it might fit.

Ken W7EKB