Metal Rescue is essentially the same as Evaporust, same approach to rust removal, chelating agents.
To make Evaporust last longer, and work even better, try the following:
Use it in a warm place and it will work faster.
Pre clean the parts before they go into the Evaporust. Clean all oils and grease off, and brush any loose rust away. Evaporust has surfactants (detergent) in it. If, after a while it no longer makes a few soapy bubbles when you pour it, then add a few drops of dish washing detergent to the mix. Don't overdo it, that seems to slow it down. The more rust on the parts you put in, the shorter time the solution will last.
Keep the container well covered while soaking parts in Evaporust. If it loses water by evaporation, it will not work as well. You can add a little more water, but it is a guessing game. It works best at the original dilution.
Make sure the parts are COMPLETELY covered with Evaporust. If part is sticking up out of the solution, it will get etched at the liquid to air line, leaving an ugly etched line there that is not easily removed.
It is said that you can cover large parts with paper towels or rags soaked in Evaporust to remove rust. I have not tried that and I really have my doubts that method will work well unless kept constantly and completely wetted with the Evaporust and prevented from drying out anywhere. Does anybody here have experience with that?
When you put the parts in the Evaporust, lay them so the rusty areas are well presented to large amounts of Evaporust. If the really rusty parts are against the bottom of the container or against other parts, the rust will be removed much more slowly on those sections. Slosh the parts around a bit after you pour the Evaporust in the container. Try to work any and all air bubbles out. After a day or so, depending on the amount of rust, take the parts out of the Evaporust and brush them down with a stiff nylon brush and fresh water. I use hot water. Hit all the crevices, threads, and internal surfaces as well. If there is still rust on any of the parts, put them back in for another day or so. Lather, rinse, repeat as necessary. You can scrub off the black deposits that some of the parts will have after Evaporust. Maroon or light gray Scotchbrite will brighten them up nicely. Blast the water on the parts off with compressed air. When they are good and dry, coat them COMPLETELY with ATF. I use toothbrushes, Q-tips, bottle brushes, and whatever to make sure every bit of surface is lightly coated with the ATF. The tools or parts will look really nice at this point and will be well protected against future rust. The Evaporust can be used over and over until it is quite black and works too slowly to be worthwhile. Then it can be poured down the drain safely. If you are on a septic system, i would not do it. You do not need to wear gloves while working with Evaporust, it only reacts with iron oxide (rust). It does, however, leave your hands blackened, though it does wash off with soap and water, a brush, and some effort. Gloves are optional, but the smell that remains is not awful, but also not pleasant. Have Fun!
