[R-390] RTV for sealing, what we used before, the black stuff

[Roy Morgan]

On Apr 22, 2016, at 4:17 PM, Norman Ryan via R-390 <r-390 at mailman.qth.net> wrote:

> Tisha wrote (in part):
> 
>   If you ever have to remove the pitch or bitumen you can do it either byheating or the use of solvents….
> 
> I write:
> After digging out the bitumen (aka uckumpucky) I've had good luck cleaning up electrolytic capacitor cans with paint thinner (at room temperature).

I wonder if there is some confusion here:

Years ago I had a high value early Heath williamson amplifier whose power transformer was showing winding leakage.  The transformer was potted in “tar”.  I de-tarred the potted transformer by suspending it in a big coffee can over the charcoal grill in the back yard.  (Many current large coffee containers are plastic.)  The stuff that melted into the can was a lot like the black tar used to seal up cracks in pavement or to re-pave roads with gravel.

The stuff in electrolytic capacitors, which we on the list have in the past called Uckumpucky, may not be tar or bitumen, but rather some other stuff altogether.  The gunk that dead electrolytics leak out the end seals is not tar at all.

Can anyone clarify?

Roy

Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958