Where the
world gathers for metal finishing
Q&As since 1989


-----

How to Mount Anodes?

Hello, I have setup a 15 liter tin plating tank at home for plating printed circuit boards (plate tin over copper). Bath is the acid stannous sulphate type and I have been successfully electroplating a smooth matte finish on the workpiece for the past few weeks. My main problem at the moment is mounting the anodes. Currently I am using two tin anodes in shape of long rods. These were cast myself using a length of angle iron with welded end caps and melting the tin with a gas torch. The rods are rather thin, 1/2" x 1/2". The anodes dissolved quicker closer to the cathode, which is at the top of the tank.

Eventually this erosion of the anode will probably break and fall to the bottom of the tank. Ideally I would like to make anodes of a thick block shape and submerge it midway into the tank. All the plating tank designs I have seen do not completely submerge the anodes so tops stick out. The electrical connection is then made at the top without worry of dissolving. I am looking for a simple way to make a electrical connection to an anode completely submerged and not have it dissolve and therefore contaminate the bath with copper. Another option may be simply use larger anodes and not worry about the non uniform erosion since it will be long time before they need be replacing. I guess I'm looking for techniques of fastening metal anodes in plating tanks. Any help greatly appreciated.

Adam Seychell
- Melbourne, Australia
2000

---

The severe erosion is actually just below the air-liquid interface. Cheapest way -tinkertoy, but works- is to fasten a piece of pvc pipe to the top of the anode that extends about 2 inches below the liquid level.

I would prefer to make the anodes about 1 inch and remake them, recycling the bulk of the tin. You need to watch the anode cathode ratio. Tin plate goes to pot when the anode area gets too small.

James Watts
- Navarre, Florida
2000