Patrick wrote ...

im thinking of making a tray of hard epoxy, filling it with Silicone tub and tile caulk, then pressing the resistors in to the wet silicone. if neccasary the silicone can be removed, and the resistors reused, this removes the hazard of springing a oil leak. since the silicone and epoxy are both solids.

i was advised by senior app engineer Richard Drawz, from Caddock not to hard encapsulate the resistors, as a difference in TCo would cause gaps between the resistor body and insulator, where corona will surely pop up. if expansion doesnt cause gaps, then shrinkage may cause cracking of the resistor Al2O body/core. so he advised only oil be used. He speculated that silicone would reduce heat dissipation over what is normally air, oil would increase effective wattage.

i wonder if silicone would conform to any dimensional changes while not being a liquid.

for background see these previous threads:







this is a great pic, from LutzH, his FuG.

'Samuel M. Goldwasser ' wrote ...
A variety of devices could be placed across R2 to limit the maximum voltage present in the event of a breakdown. Suitable devices include neon light bulbs (NE2s without resistors)… The neon bulb is good since its impedance is essentially infinite until its breakdown of 90 volts or so is reached.