[EdHolland]

I was reading around the web over the last few days about potentiometers. Searching a 2 Meg pot, with switch and tone/loudness tap, I started wondering about options to repair the damaged track on the existing pot for my radio.

This rather interesting thread came up: https://www.radiomuseum.org/forum/repair...eters.html

Looking further, I was intrigued as to how the audio taper or Logarithmic pots are produced. That yielded this web page http://www.resistorguide.com/potentiometer-taper/

This implies that, except for the most specialised components the "curve" is really an approximation, achieved with a two part track, the first part having a relatively low resistance change vs pot roitation, and the second part having much greater resistance. 

OK, knowing this, how can we ever make a pot new again? Conductive materials are needed, which can replicate the necessary resistances when deposited on a surface.

A while back, I bought some conductive carbon paint. This certainly conducts, but far too low resistance for a 2 MOhm track, without reformulating it.

This weekend, I was tasked with restoring and cleaning up an old wood burning stove. Up to my eyes in stove blacking, I had a notion to test this, rubbed on to a piece of paper. Quite promising results could be achieved with this approach. Next is to test on a piece of Phenolic.

Of course, this is a crazy project.... but I would really like to experiment if this could put the original pot back in my radio, rather than the modern replacement it has. at the moment. 

Any other experience among forum members?

Cheers

Ed