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Old 16-04-23, 21:04
David Dunlop David Dunlop is offline
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Join Date: Feb 2006
Location: Winnipeg, MB
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Default Carriers No. 4 - Ground Terminals

After some further careful fine sanding, scrubbing with a a small brass wire brush and several cleaners followed by a final wipe with acetone, my Carriers No. 4 has finally revealed its secret copper plating around the front Ground Terminal on the frame of the Cradle assembly.

The textured surface of the copper plate suggests this particular Carriers No. 4 underwent sand blasting prior to getting its postwar coat of NATO Green paint, so the odds of my recovering any of the factory original No. 2 Brown finish, have now been reduced significantly. But that is OK right now. I am just thrilled to have found this plating.

All of this prompted me to revisit the internet for more information on plating techniques and this particular process is apparently referred to as either ‘Selective Plating’, or ‘Brush Plating’. It is used for plating small, specific parts of larger objects that do not need full immersion tank plating, or for plating repairs. The same general principles apply as per tank plating. The recipient part is the ‘cathode’ connected to the negative side of a DC current. The ‘anode’ is still a piece of the particular metal that is to be the plating (copper, zinc, nickel, etc.) and it is connected to the positive side of the DC current, but the anode is actually inside an insulted tube, surrounded by an absorbent filling of fabric, filled with the appropriate electrolytic solution. The lower end of this tube is a wick allowing the solution to contact the cathode material being plated, thereby completing the electroplating circuit.

When I read all this, it jogged my memory of one of my uncles back in the 1950’s. He owned a 1956 Oldsmobile convertible, red and white. I cannot recall which model, but he got a scuff on the front bumper one summer and it was repaired by somebody who drove to his home and had all the kit in the back of a panel delivery truck. I watched him smooth down the scuff with some emory paper and then attach a ‘battery cable’ to one end of the bumper. He then pulled out a second cable with what looked like a small section of broom handle fitted to the end and start moving it back and forth over the scuff slowly for several minutes. And the scuff slowly disappeared. When this chap was finished, you could not tell the bumper had ever been scuffed and my uncle was very pleased.

So now I need to do some more internet reading to see if there are any DIY at home techniques documented for Selective, or Brush, Plating. This may be another handy skill to acquire.


David
Attached Thumbnails
Front Ground Terminal Copper Plating 3.JPG  

Last edited by David Dunlop; 16-04-23 at 21:18.
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