12-11-2015, 09:38 AM
Just a little note on rebuilding electrolytics. Some people pull the aluminum center contact post from the base and replace it with a brass screw when rebuilding because they have problems soldering to the aluminum. I just use the aluminum center post with the aluminum fins removed, and cut down to about 1/2 inch above the rubber insulator. I sand the surface of the stub well, and immediately paint on some of the liquid flux I make by dissolving violin rosin in some rubbing alcohol. This helps keep the aluminum from oxidizing which is why it is hard to solder to. The aluminum will begin to oxidize immediately as soon as its clean surface is exposed to air. The liquid flux coats it and minimizes that. I also use an old fashioned Weller 100-150 watt gun, not a pencil. Pencils are fine for solid state work, but for most of the old fashioned chassis work, I prefer the Weller gun. For this application it is very necessary, one needs the heat. Heat the contact until the solder will flow well. Keep rubbing it when it is melted, and it will begin to stick to the aluminum well as it fuses with the surface molecules of aluminum. Once the center post is tinned this way, you can just wrap the + lead from the replacement condenser tightly around the tinned area, and solder as usual.