[jim sewell]

Kieth
What ever power source you use , you need an amp meter in the circuit ( to measure the amps ) so that you can regulate the amperage .
To regulate the amps , shift the part to be cleaned and the sacrificial further apart , draw the sacrificial item part way out of the solution , change the size of your sacrificial part ( stainless steel lasts longer )or have a weaker solution .( normal solution 1 table spoon washing soda per gallon )
Do not exceed the maximum amps available from your power source ie battery charger , transformer etc To do a door I suggest you build yourself a box and line it with heavy plastic , stand the door up and leave about 300 mm distance to your sacrificial part , use at least an 8 amp battery charger and regulate the amps at about 6 amps , remember this process works in a straight line meaning you will need to turn the door around and it may not me very effective say in a blitz door where you cannot get to the actual surface , for that one you may be better off with molassis mixed on a 5 to one ratio with water .

Have attached a pic of a GMC guard being done , I have used a sheet of corregated iron as the sacrificial piece and my power source was my ford V8 WW 2 Welder with the engine idling I could get 50 amps out of it hence the hydrogen bubbles you can see there , for insulation between the parts I used house bricks and shade cloth . WARNING . Do not pull the leads off as it is discharging as a spark may ignite the hydrogen bubbles when using high amperages .
Regards
Jim S.