Getting Rid of Rust on Cast Iron

The band saw before the work began.

About five years ago I owned a red Volkswagen Karmann Ghia. It had some rust problems (like most cars from the 1970s that lived through Pennsylvania winters), and so eventually I was faced with a tough choice. Live with the cancerous rust or do a frame-off restoration (translation: something that married magazine editors cannot afford).

And that’s the same choice I thought I faced when I started work on this circa-1979 Rockwell/Delta band saw that had never been turned on. The cast-iron table looked rough. And the top wheel cover looked like it had rusted in a couple places and dribbled rust all over the gray paint.
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So I took a deep breath and picked up a bottle of Rust Free, made by Boeshield. The deep breath was because the stuff is made using phosphoric acid, which is stinky, though not likely to really knock you on your can, according to the MSDS safety sheet.

I sprayed it on all the rusty bits and waited five minutes. Then I wiped down everything with a soapy warm rag. I was pleasantly surprised. The big news: The rust on the top wheel cover wasn’t from the rusting of the cover. The saw had obviously been sitting under a rusty pipe that was trying to turn the saw into a stalagtite or stalagmite or whatever. It was cosmetic. It was, after a swipe, gone forever.

The rust on the table was harder to remove, but a couple applications of Rust Free made the top look better than my well-cared for Unisaw’s top.
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I squirted all the guides and trunnions with Liquid Wrench (the Liquid Wrench people had sent Senior Editor Robert Lang a case of the stuff , we eat it on crackers sometimes). Everything on the saw immediately got loose and movable.

Thing were looking up.

Then I took a look in the base. The motor is 3-phase. I need a single-phase motor in my shop. Dang. Time to get scrounging.

With the Karmann Ghia, I eventually sold it to a dealer for $800 who then sold it to someone who specializes in restorations. Whenever I see a Karmann Ghia in town, I wonder if it’s mine. That’s not going to happen with this band saw. I attached the newly cleaned table to the saw’s trunnions late last night.

Totally solid.

– Christopher Schwarz