Mike,

How long do you keep the barrels in the electrolysis? I'm curious on that part. I have used this method many times to clean steel including barrels. I have found that it converts all iron oxide to black oxide and that it is reasonably easy to remove with steel wool or any form of abrasive pad. My last set of barrels were grey patina with no amount of original finish left.

So I wonder if the original bluing stays as a result of time in the tank.

I use it as an efficient method to convert all rust to black oxide everywhere on the barrels, inside an out prior to refinishing.

Jason