Hey Upsman,
I'm putting a used tank in my '47. What I have learned is:
1.) You have it leak tested.
2.) You have it cleaned.
3.) You have it relined.
4.) A local radiator shop will do all this for me for approximately $80.00. Repairs are extra. Repairs on a seam leak are not worth trying.
Since I bought a used tank I asked the questions, how clean is it, and does it leak. The answers were good enough to satisfy me, and the seller is a fellow stovebolter, so I took a chance on it sight unseen.
I'm not sure how they leak test it, the seller says he filled it with soapy water and it held it. As far as cleaning, the shop uses some kind of acid bath. One of my options was an aluminum tank a guy had for sale. The radiator shop said they couldn't clean it, there would be nothing left. For relining it, they have some kind of rubberized paint type stuff they pour in, agitate the tank until it's coated and then pour out the excess.
It seems to me that it's worth the $80 to let the pros do this. I don't want to mess with the acid, waste (and have to dispose of) the acid and a couple gallons of liner stuff, and who wants to shake a gas tank around until you think you have it all coated? If it needs repairs, I may do that myself. I can weld and braze. I'm assuming repairs must be made before the cleaning/lining process. Wouldn't want to burn off the coating.
