HV tracking across flexible PCB strips

tony duell ard at p850ug1.demon.co.uk
Mon May 11 13:01:07 CDT 2015

> Question is, once it's all thoroughly dry, what would be the most
> appropriate way of re-sealing everything? Would silicone sealant perhaps do
> the job (dispensing with the top layer of the sandwich entirely and just
> coating the bottom layer/traces) and stand up to the HV OK?  Or some form
> of glue?

Firslty, some silicone sealants cure by eliminating ethanoic (acetic) acid (they smell
like vinegar) which is probably a very bad idea here. Secondly, HV finds a way
to leak if it possibly can ;-). I found by bitter practical experience that the plastic
used for electrical wall plates would not stand 30kV (I was trying to use a cut-down
blanking plate to stop a 30kV flashover, didn't do a darn thing!).

I would try to re-make the 'sandwich'. At one time you could get special HV
glues and 'anti corona dope'. With the demise of CRT-based devices I suspect
such things are going to be very hard to find now, but you can try.

Do you have any idea as to the voltage involved?


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