You could theoretically of you used a brass cleaning rod instead of steel and reversed the polarity, probably why the commercial units use a stainless or mild steel rod.
I've been anodizing aluminum here for years. Same process, different electrolyte, more juice.
Whatever you use (if you do it), I'd strongly recommend treating the bore immediately afterward with gun oil because the process will strip any oil and leave the metal exposed to oxidation (rust).
Cold anodizing is the same process (not really cold as the electrolyte (sulfuric acid/distilled water) gets hot from the reaction. Thats how you determine what level the electrolysis is progressing at, if the electrolyte boils, it's too much amperage.
I do my anodizing outside of the shop, in a shed because the acid fumes would destroy my machinery right away (and my lungs) so good ventilation is necessary.
I believe the commercial units employ current sensing electronics to limit the 'cooking' time. Not sure, but, over cooking the bore could cause issues with the parent metal.
I use a manual heavy duty battery charger for the cold anodize I do and I imagine a small manual charger (less than 2 amps) would work for the bore cleaner too. You don't want a lot of amps because the area of electrolysis is small, the electrolyte solution is not much either. Big amps equal hot solution and that you don't want because it would boil dry and the less solution, the higher concentration of the electrolyte itself, because the carrier (in this case water) boils away, that changes the specific gravity of the electrolyte and could actually cause etching of the parent metal (your bore) and thats no good.
Look at it like a storage battery in your car. You never add acid (sulfuric), just water, preferably distilled (no suspended minerals). The acid in your battery never leaves, the water does.
A maintenance free (flooded cell) battery is nothing more than a conventional battery with a mechanical means for condensing the off gassed water vapor and returning it to the cells, hence the funny caps. Those caps are little condensing units and no flooded cell battery is 'sealed' despite what the maker claims. If it was sealed to the atmosphere, it would explode from the pressure of off gassing, a normal condition of the charge-discharge cycle.
Actually, a car battery operates in a very similar fashion to the bore cleaner. Different electrolyte and different metals but the same principle. Batteries eventually die because the process of charging and discharging thousands of times, produces lead sulfate, which sinks to the bottom of the battery and eventually shorts the plates out.
Sorry about the thread hi-jack but I imagine that people wonder how a car battery works.
The bore cleaner principle is the same, just different electrolyte, less juice (amps) and less time in process.