There should be no reason for a stainless steel drum to develop holes from being used as an electrolysis tank, The only concern I would have is possible electric shock as you are using the positive attached to the tank(drum) so you would have to be careful about what the negative comes in contact with especially since you are working with wet objects and a water solution specifically designed to conduct electricity.
Your current is flowing negative to positive so no matter/material/metal is being taken from the barrel it is being deposited onto the barrel , you are basically electroplating the barrel with ferrous oxide(rust)
[size=12]Any anode (which is 'sacrificial') will degrade and eventually develop holes/breach spots, even Stainless Steel. The length of time for this to occur is much longer when using SS... and will vary depending on the 'type' and gauge (thickness) of the SS, and usage frequency. It is still way longer lasting then regular steel, and don't ever use a galvanized trash can as an anode... it will breach quickly,,,, very quickly...
In the picture above, the entire top rim of my SS barrel is covered with a split length of clear vinyl tubing which allow me to lay my Negative conducting rod straight across the top... which also has lengths of clear vinyl tubing at the contact points (double insulation)... :)
It is also sitting in a plastic (hot water heater) drain tray with overflow drain hose attached, just in case the side weld breaches first. This also insulates the SS drum from the concrete floor which could conduct current, and zap little ole me. ;D [/size]
