Electrolytic rust removal...

[Victor3]

 Don't know if this has been discussed here before.

 I recently got a 40mm rifled bbl section. Bore is pretty good, but since this is going to be for a 'new' cannon, I wanted to be sure the bore was as rust free as possible.

 Hard to get a good pic, but you can see there are a few rust spots. These didn't come out completely with brushing/swabbing...



 I didn't want to use acid or abrasives, so I got this stuff together. All that's needed is a battery charger, sodium carbonate, water, bucket, a steel rod, some rubber bushings and something to plug the end of the bore...



 There are a lot of websites that give details of how this works, so I won't go into detail. You mix the SC with water, pour it into the bore, put your rod in and attach the leads...



 In a few minutes you can see some scum forming on top of the water...



 Let it sit (for a few hours if the rust is light, a day or more if it's heavy), then take it apart, pour the water out, and scrub the bore. Some black stuff will come out of the bore, but the rust should be gone.

 I let my setup cook for 3 hours, and the bore looks good to go now.

[Soot]

Good tip, I forgot you could do that. I saw an entire Messerschmitt engine that had been underwater since WW2 cleaned that way.

[Rickk]

I use the same trick when I restore rusty antique kerosene lanterns. It removes the rust, but leaves any tin plating and good steel that is still there completely intact.

"sodium carbonate" is commonly called "washing soda" (different than Baking soda) and can usually be found in the supermarket right next to the baking soda.

Rick

[FTB1-SS]

Thanks for the very useful info!

[Victor3]

"sodium carbonate" is commonly called "washing soda" (different than Baking soda) and can usually be found in the supermarket right next to the baking soda.

Rick

 I spread baking soda on a piece of aluminum foil and put it in the oven at 325 for an hour. This converts it to sodium carbonate by removing the "bi" from the bicarbonate.

[Rickk]

Pool supply places usually carry somethign called "pH-up", which is also sodium carbonate. It costs more than Arm & Hammer "Washing soda" though. They are both the same stuff.