If you're like me, the cast iron in your shop sits atop the most prized tools you have. Those tops are solid, durable, stay dead flat, and make working wood just a bit easier. But to keep them at their best takes a bit of routine work, fending off rust and staining doesn't take much but make sure you do it. Here's how.
Some background: I'm a bit excited, because I just got a new toy for the shop. The Laguna 14 twelve band saw has been on my radar for a while, but the sticker price was keeping it way out of my budget until I found one on Craigslist last week. A few hours later it was firmly installed in my shop and ready for a brief overhaul.
It had been in a shop for a few years, well used but still running well. The dust wasn't an issue, but some surface rust and staining needed to go.
Rust and staining happens on cast iron when moisture or liquid is allowed to sit on the surface, because even though cast iron is solid, it's still porous and the metal reacts to the moisture by oxidizing.
Step 1: Wipe it off - The dust and dirt need to be brushed and wiped off so you can see what you're working with. I use a shop brush or old paint brush to get it cleaned of debris, and to clean out miter gauge slots and tight corners.
Step 2: Apply mineral spirits - Use a clean rag to wipe on a layer of mineral spirits and let it sit for 10-15 minutes.
Step 3: Work on the stains - Add additional mineral spirits and scrub the top with a fine steel wool pad, paying attention to the stained and rusted areas. Scrub in a back-to-front motion, to keep the grain of the pattern parallel to the blade. For more intense rust, you can try 400 or 600-grit wet/dry sandpaper, lubricated with mineral spirits or a little WD-40.
Step 4: Wipe clean - Once the stains have been removed, wipe the entire surface clean with a new rag, and additional mineral spirits if necessary. The surface may still have minor staining, but as long as it is smooth it will perform well.
Step 5: Protect the surface - Some people like to use carnuba or similar car waxes to give a slippery, protected surface, but that tends to attract dust and gum up over time. I have really been impressed with GlideCote ($20) to give it a smooth and protected surface that lasts.
With a bit of elbow grease the top looks great, and wood slides over it effortlessly enough to make me keep sneaking out to the shop to play with my new toy! If your cast iron tops need a bit of TLC, it's time to make it happen, you'll be glad you did.