One more step ,
i'm doing the gas tank now,
first of all had to get rid of the surface rust on the inside of the tanks, i used Rust Remover for hat and let it rest for the night .
after reaching bare metal, i rinsed it with water and dried the hole thing .
step 2 is coating the tank from the inside ,i chose a specific epoxy material that is used for industrial chemical and fuel tanks. (Tnemec 61
http://www.tnemec.com/product/view/Series-61-TnemeLiner)
After mixing the 2 components and adding some thinner i filled the tank with 2 liters and turned it over and over so it will reach every inch on it.
The immersion time is 5-7 days, after a week the final result is an Emile-like top coating, completly rust proof .
the tank is ready for 60 more years of servicing