Repairing paper caps

May 04, 2005 42 Replies

A question re 1920s paper capacitors housed in tins filled with wax: theyre always very leaky, presumably due to damp in the paper. Is it workable to dry them out in an oven at just over 100C? Does it work? Or is this not a wise idea with the wax?



Trailing edge stuff.


NT



Just empty out the tin, put in a modern cap, and backfill it with wax.

Cheers! Rich

What Rich said, and look for the "boatanchors" newsgroup -- I think it's rec.radio.boatanchors, but there may be an "amateur" in there also. Just search on the unique part...

Tim Wescott Wescott Design Services http://www.wescottdesign.com

I read in sci.electronics.design that Genome wrote (in ) about 'Repairing paper caps', on Wed, 4 May 2005:

Keep the original wax? You can still get electrical waxes, but you may have to buy a lot.

Be sure to use polystyrene capacitors. (;-)

No, don't.

Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Candle-making wax from the craft store with a drop or two of yellow food coloring?

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

Most capacitors of that period in cans were wet electrolytic or oil filled paper caps. The electrolytic types were in round cylinder cans often with a threaded bottom end while oil filled were usually in square or rectangular cans. Most wax capacitors were in paper tubes, not metal cans. Be sure the caps you are talking about are NOT oil filled types because these things were filled with Chlorinated bi-phenols and are toxic! A big deal was made of these things a few years ago because of the dioxin they may contain. Remember Love Canal? One brand was GE Pyronol. Stay away from this stuff. If your caps are really wax then they should be ok otherwise it's not wise to fool caps from this period. Take them to a hazmat place and get rid of them. No cap is worth your health. Bob

No, it tends to introduce hum into the signals.

Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Oh, I guess you've been stung by that one before.

John

Be sure and rescue a couple of baby fur seals on your way. Gotta get enviro-mental, you know!

Cheers! Rich ------ "Self-abuse is the most certain road to the grave." -- Dr. George M. Calhoun, 1855

I read in sci.electronics.design that John Larkin wrote (in ) about 'Repairing paper caps', on Wed, 4 May 2005:

Yes, but not as many as 50 hurts. At some times in the year, it's more of a drone than a hum.

Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

You should try a comb filter.

Bob

Q. What do a Moebius strip and an argument with a woman have in common? A. They both only have one side.

I just hived off the problem to someone else.

Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in sci.electronics.design that snipped-for-privacy@meeow.co.uk wrote (in ) about 'Repairing paper caps', on Wed, 4 May 2005:

You may not get a fire from the wax but I doubt that the caps will be any good. They corrode at the points where the foil meets the copper lead-out wire, and internally in the winding the paper dielectric pierced by crystals of corrosion compounds (aluminium 'waxate' - waxes are weak organic acids).

Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

At one time, I tried to make a candle. The instructions recommend adding stearic acid to ordinary paraffin to make it harder. The capacitor wax I remember was much softer, so you'd want the oposite effect. For some reason, I seem to remember seeing "beeswax" mentioned a millennium ago (besides in the thread :-) ), but I won't swear to it. It does sound logical, though.

Cheers! Rich

This thread is really starting to bug me.

Cheers! Rich

Aluminium Stearate?

~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk

I think stearic acid is a bit too long a molecule for electrical waxes, but maybe not.

Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except \'What is a Moebius strip?\' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

snipped-for-privacy@meeow.co.uk wrote in news:1115212714.520312.155440 @f14g2000cwb.googlegroups.com:

just throw them away and replace with modern equivalents...

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