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Most expensive table saws feature cast iron table tops and, as a result, can rust over time. This rust is problematic: not only does it degrade the table top, but it can permanently damage your workpiece. We will show you how to remove rust from your cast iron table saw top to extend its useful life.
We’ll also cover some preventative measures you can take to avoid further oxidation and protect the metal.
Why a Table Saw Top Rusts
Table saw tops are generally made from one of two metals. The smallest and lightest table saws have aluminum tops, as the lightweight design makes them perfect for bringing to the job site.
For a table saw that won’t be leaving the workshop, cast iron is the preferred material. It’s heavy mass helps control vibration during use, making cast iron topped table saws generally more accurate and easier to use than their aluminum counterparts.
There is a drawback to cast iron, though: rust. When iron is exposed to moisture, the result is a chemical process called ‘oxidation’. As this process occurs, the cast iron degrades into iron oxide — the red, flaky substance we call ‘rust’.
How to Clean a Cast Iron Table Saw
Cleaning the rust off your table saw is an easy job that should be completed frequently. Removing rust as soon as you notice it will preserve the precision of your table saw. All you need is an abrader, a lubricant, and a rust protectant.
- Remove the table saw accessories and ensure your safety. Unplug the table saw to prevent injury from an accidental start. The table saw blade, blade insert, miter gauge, table saw fence, and rails all need to come off. Use eye protection and cover your hands using nitrile gloves. Avoid latex and vinyl gloves, as they will be degraded by petroleum based solvents like mineral spirits.
- Choose your abrader. The best choice for removing rust from cast iron is a synthetic fiber scrub pad. Steel wool or sandpaper will effectively remove the rust, but they can also scratch the surface of the cast iron, exposing more of it to air and moisture. Over time, the result is the build-up of even more rust.
- Choose your lubricant. Most shops have WD-40 already on hand; this can be used to lubricate the table top during cleaning. Because it evaporates rapidly, you will likely need to reapply several times during the cleaning process to ensure adequate lubrication. A superior choice to WD-40 would be mineral spirits. Mineral spirits provide enough lubrication for proper cleaning, and they also leave behind a protective coat of oil.
- Scour the table saw top. Spray or spread the lubricant onto the table top. Scrub it forcefully using your abrasive material. A light layer of rust should easily flake away, revealing the dark metal underneath. If you need more scouring power, you can place your random orbital sander on top of the scouring pad and turn it on. The motion, speed, and vibration should help remove heavy rust. However, if the layer of rust is already very thick, you may not be able to clear the table top. Saws in this condition are still able to be used for rough cuts, although they are no longer capable of precision woodworking.
- Apply a protective coating. If you used mineral oil, wipe away any excess. There are two options for protecting your table saw top from future rust. Woodworking supply retailers sell specialty commercial products intended to protect and lubricate your work surface, allowing superior slide of work pieces. Paste wax is also an option, but avoid versions that contain silicone. Silicone paste wax (like the kind used for cars) can work its way into the pores of certain types of wood, so it’s best to keep it away from your table saw.
Preventing Rust Accumulation On a Table Saw Top
Table saws that are priced at $1,000 or higher are typically made with high quality parts, including a heavy duty cast iron table top.
Exposure to the air will inevitably cause a cast iron table saw top to develop rust. You can minimize the rate at which rust develops by decreasing the amount of time the table top is exposed to the air.
To do this, cut a sheet of plywood or MDF to the same dimensions as your table saw. When the machine is not in use, lower the blade and cover the table.
Plywood and MDF are also good solutions for table saws that have too much rust to be removed. Covering the table top with one of these materials provides a smooth and flat surface for the workpiece to slide across.
Inspect the table saw before each use, noting any rust accumulation. After cleaning the rust off and applying a protective layer of paste wax or rust prevention spray, your table saw is ready to use. Apply a protective layer of mineral oil when you finish with work for the day.
Do Aluminum Table Saw Tops Rust?
The information above applies exclusively to cast iron table saw tops. Cast iron is the most popular material for table tops, but portable saw models and cheaper table saws are often constructed with aluminum instead. So, how do you care for an aluminum table saw top?
Contrary to popular belief, aluminum oxidizes when exposed to air. But instead of the red, flaky substance we know as rust, aluminum oxide is hard and gray. Rather than degrading the metal and causing it to lose mass, the oxidization process actually protects and hardens aluminum, providing some resistance to dings and scratches.
To maintain an aluminum table saw, wipe it down with a solvent after each use. Distilled white vinegar is an easy and cheap solvent. Periodically apply a non-silicone based paste wax to help the wood slide across the surface of your table saw.
Cleaning rust off a cast iron table saw top is a simple and easy maintenance job that should take less than an hour. To complete this project you will need to remove all the accessories from your table saw. Scour the table saw top using an abrader and a lubricant of your choice.
When the rust is removed, apply a protective coating to delay the return of rust. Consider using a piece of plywood or MDF as a cover for your table saw. Aluminum table saw tops do not rust, but will benefit from regular maintenance.