I read a Article in Street Rod Builder about using Muriatic Acid to remove rust. I tried it out this weekend. Man it worked great never seen anything like it. I have use all type of Phosphoric acids and none of them are like this. I bought it from Home Depot for about 3 bucks a gallon. You spray it on or soak the part and it eats the thickest rust off with no problem then just rinse it off with water. Be sure to get it out of the seams with a air hose and rise again. then paint or apply some type of metal prep like ZR's prep step.
WARNING
MUST READ!!!!
Muriatic Acid is very dangerous if your not careful. When using it you must use your NASA approved Chemical Warfare Suit. No really Be sure to use a respirator like for spraying paint, Protective eye goggles Not safety glasses and some latex gloves and you'll be fine. Use it with caution. I did mine on my deck with no problem. Dont use on cement it will eat a hole in it.
Great for small parts and body parts that have been sand blasted and still has pitted rust.
Good luck and be safe
