Depends on the amount of rust & how big the part is. 1gal & a recirc pump will do an M2 (the gun, not the tank 😉 )

There’s another company that makes similar stuff under the name of Rusteco.

If there’s no UK distributor etc I may have to call my step bro & have him start importing it… if it’s financially viable.

I use stuff made by Bilt Hamber……

http://forum.keypublishing.co.uk/showthread.php?t=66007&highlight=bilt