Did you know that Mastercoat® Permanent Rust Sealer/Surfacer/Primer can also be used to seal a gas tank? Here’s how:
1.) Remove gas tank from vehicle. Remove sending unit. Shine a flashlight inside to see how much rust is in the tank. Any screws or threaded fittings should be coated with grease and run halfway into the tank. This is so the sealer doesn’t weld the screws into the tank. Be sure to wear rubber gloves when handling the Mastercoat Metal Prep and Mastercoat® Permanent Rust Sealer.
2.) Use an airhose to blow out any dirt that may be inside gas tank.
3.) Use a cleaning agent such as Spray Nine to clean inside of tank. Rinse thoroughly and let dry.
Captain Lee’s Metal Prep no longer sold by us; check out or own Mastercoat® Metal Prep.
4.) Pour Metal Prep into gas tank and slosh throughout. This accomplishes three things: it etches any remaining galvanized, dissolves any surface rust, and leaves a zinc phosphate coating to adhere to. If it’s heavily rusted, let the metal prep soak, say for instance on the bottom of the tank. Then after an hour or so, turn it on its side. After the tank is cleaned out, pour back out again into the container through a cloth. It then can be reused.
5.) After metal prep is completely dry, pour Mastercoat rust sealer into tank and rotate it to cover the entire inside. If the tank has pinholes, paint the outside first, and then slosh the inside. This will prevent icicles from hanging from your tank.
6.) Stand tank on end to let sealer completely run out. A nice thin coat is desired with no puddling. Let cure for 48 hours before putting gas in tank.