Reply to "Icky Rust in Fuel Tank"

I've used muratic acid to remove rust from gas tanks and all kinds of steel/iron parts with great success. Muratic acid is dilute (Typically about 20% by volume) hydrochloric acid. It's commonly used to etch concrete, clean swimming pools, etc. and can be purchased at hardware and spoll suppliy retailers. It will definitely dissolve all rust (iron oxide). It will also off-gas chroline so do it outside and don't breath the fumes. If you use it as purchased and dont dilute it, I'd recommend a gallon or two (it's inexpensive) and reposition your tank so that all surfaces will be immersed for an hour or two each. Alternately, you can use several gallons, fill the tank full and let it set for several days (dilute solutions are slower acting). When your through, if you dilute it with water, say 50:1 or better, it's realtively harmless and you could wash down your driveway with it. Even at 20% it won't burn you but may stain your skin or mildly irritate. Where latex gloves. Make sure the tank is vented and that you do this outside. If you seal the tank it will off-gas to potentially explosive pressure. You also need to make sure that you remove the filler neck, the sending unit, and anything that is not steel. It will completely dissolve aluminum and zinc (try it with a beer can). When your through, you will have the most rust-free tank you've ever seen, but you're not done. Mix a box of baking soda in with a tank of water and this will neutralize the residual acid on the inside surface of the tank and prevent any acid from migrating into your carb. and attacking any aluminum surfaces in your engine. After you do this drain well and set it in the sun to dry. All you'll need to do is poke around to make sure that you tank wasn't rusted through anywhere. -You'll be done with rust forever. By the way, iron oxide (rust) will not stick to a magnet. This method might pick up pieces that still have some ferrous content but not iron oxide. Good luck.