Kent K9ZTV, made the point off-line that burnishing (rubbing to smooth or polish) contacts on modern keys might not be a good idea. He observed that any abrasive rubbing or polishing might damage special finishes or alloys that the manufacturer may have used on them.
I was speaking of my half-century old keys that have brass (or bronze) contacts that have been repeatedly ground and burnished to remove pits and burns caused by arcing when keying high voltage lines in old transmitters. As John mentioned, a reasonable current through those contacts actually served to help keep them clean. Modern very low voltage/low current keying circuits don't do that and the contacts easily become intermittent as they collect a coat of oxides and dirt. Such contacts need no such delicate care as perhaps modern contacts might, although it'd be foolish damage them further needlessly. (Some old keys do have silver contacts which should be treated with care, especially if they're plated and not solid silver. Silver oxide is a good conductor, so even if they appear black they are still good electrical contacts. If they become intermittent it's not because they are oxidized but because they are actually dirty with a film covering the silver. Very gentle wiping should restore good contact.) On my old keys with their bronze contacts, burnishing is definitely in order if nothing else works and they've survived that treatment hundreds of times over the decades. Recently I've found that De-Oxit does the job even better as I described. If I bought a brand new key I'd check with the manufacturer about how they recommend cleaning the contacts because, sooner or later, they're sure to need it. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
