Topband: Cleaning Roller-Inductors

[Dick and Adele Bingham]

Greetings everyone

regarding ===>

"Date: Sun, 11 Apr 2004 17:23:54 +0930
From: "George Stewart (VK5ALS)" <ggstew at bigpond.net.au>
To: "Topband" <topband at contesting.com>
Subject: Topband: Rejuvenating WW2 vintage roller inductors?
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Hi topbanders,

Has anybody successfully rejuvenated the type of roller inductor that
was found in WW2 transmitters? The ones I have are wound on a 2 inch
diameter ceramic material and there are 36 turns over a length of 5.25
inches the wire used is 1/8th of inch in diameter and was originally
silver plated.

A while ago I cleaned a similar inductor using a contact cleaning spray
which in retrospect was not very smart as it would probably leave a film
of conductive lubricant between the turns.

Would the type of ceramic used handle being steam cleaned with a small
domestic steam cleaner? Another idea that passed through my mind was to
put it in the dish washing machine without the normal dish washing
powder as I have seen what happens to a silver spoon if accidentally put
for a normal wash.

What about resilvering the wire when all is clean? I have never tried it
but from memory a small DC voltage applied and using spent hypo for the
source of the silver may work??"

You can brighten the silver-plated wire on these inductors (your family dinner
silver ware too) by using the following process:

1 - Get a large bowl/plastic bucket that can totally contain the object to be 
     de-oxidized when submerged in the solution to be described

2 - Turn the bowl upside down and form pieces of aluminum foil over the outside
     of the bowl/bucket

3 - Carefully remove the formed foil, reinvert the bowl and place the bowl-shaped
     foil inside the bowl

4 - Heat to boiling sufficient water to fill the bowl and the objects to be de-oxidized

5 - Add several tablespoons of Arm&Hammer baking SODA (per quart of water) to 
     the bowl and pour in the boiling water. Then immerse the oxidized silver object
     ensuring there is a mechanical connection between the aluminum foil and the 
     silver object

6 - There should be some visible bubbling activity taking place on the silver object 
     and the aluminum foil should begin to turn black

7 - Thoroughly rinse the coil after the cleaning process to remove any baking soda
     residue.

Try this process on the family silverware too during the holiday seasons and it will
save LOTS of mess and cleaning time.

73 de Dick - w7wkr
Stehekin, WA