January 2006 Wille's Workbench Rust RemovalPosted in How To: Tech Qa on January 1, 2006 0) (
While I was in the process of restoring a "slat-grille" WWII MB jeep, I needed a way to remove the rust from salvageable small parts-nuts and bolts in particular. Why not just buy new nuts and bolts, you say? Because I wanted this Jeep to be a true restoration and as original as possible, just as it came off the assembly line. The original bolts have a special manufacturer's mark on their head. There are some aftermarket copies available, but not for all sizes. I do have a blast cabinet and have used a wide variety of different media to clean parts with, but find it difficult to hold a small item, like a 7/16-inch bolt, and pressure blast it.
A rotary wire brush is one alternative, but again holding the part can be difficult. Clamping pliers such as Vise-Grips work much better than fingers, especially when the part gets sucked into the spinning brush, but still accidents happen. Maybe even a piece of the wire brush will come off and stick you in the eye.
What about chemical stripping? Believe it or not, Coca-Cola works, and most likely so would Pepsi. Pour some into a container, drop your part in, and in a couple of hours or days (depending on the part), it comes out somewhat rust-free. I still found some wire brushing was necessary. I don't recommend drinking the Coke after you've used it for such, as it's flat and tastes mighty funny. Then again, some people will drink anything.
Muriatic acid: Great stuff for removing rust on large and small parts, bad stuff for eating away skin, eyeballs, lungs, and such. Elbow-length rubber gloves, rubber apron, and face shield should be used around this stuff, with a water wash readily available. The fumes do terrible things to your respiratory tract, so try not to breathe around it. OK, that's a bit difficult to hold your breath and work for more than a minute, so it's an outside process and a respirator should be worn. If you try this, monitor your soak time. Too long, and your part will just disappear.
The last process I tried was kind of interesting. I read about it in some long-forgotten title of a farm magazine. I used a Rubbermaid Action Packer box and dumped in a can of Drano-yep, good ole Drano (the stuff you unplug the drain with after your wife caught you cleaning wheel bearings in "her" kitchen sink), which I figure is mostly lye. I added about 8 gallons of water and mixed it up. Now, this alone does a pretty good job of taking off paint, but I was after rust on large items. The trick here is to use your battery charger. The positive lead goes to a 6-inch plate of stainless steel that's used as an anode. The negative lead hooks to your part. No, nothing goes boom!
I first tried it with just an 8-amp charger and not much happened-or I got in a hurry and didn't wait long enough. Maybe with a smaller volume of solution it would have worked. My 30-amp charger, however, caused the solution to get warm and bubble, and actually removed the rust. Time and temperature, as well as the size and rust on the part, determine the length of time in the solution. It does give off some fumes, but I doubt they're life-threatening if you should get a whiff of them, as long as you don't make a habit of it. OK, again it's an outside job, and you should probably wear a respirator. No, a hankie around the mouth and nose doesn't count. The solution is weak enough, should you get some on your skin, that you have a minute or two to wash it off as it won't make an instant hole through and through. However, eye protection is always a good idea, as are rubber gloves. The Drano mix takes off paint as well as rust but leaves a fine coating of oxidation on the part. Actually takes off paint without the battery charger hooked to the part. The stronger solution takes paint off even better.
Just keep in mind, all of the above rust removal methods are just suggestions. Don't hold us responsible if they don't work or if you end up missing fingers, eyeballs, or worse. Oh yeah, one more thing-clean the oil and grease off your part first.