Why Not Use Silicone on a Cast Iron Table Saw?

Silicone

• Combining silicon with certain chemical polymers creates silicone, a slippery compound that takes either solid or liquid form. As a liquid, silicone acts as an efficient lubricant, effectively separating two solids and reducing the friction between them. Liquid silicone penetrates pores of both metal and wood, providing a long-lasting protective film. Because other substances don't bond to silicone, silicone sprays are used industrially as release agents in injection molds, preventing plastic parts from bonding to the mold. Burning the silicone away prepares the part for finishing. Water can't wash silicone away, but other solvents can clean up silicone residue.

Saw Lubricants

• Rubbing the table of a saw with a light coating of silicone lubricant eliminates the "chattering" that woodworkers notice when using a sticky table. The silicone also transfers to the wood passing over it, and traces of the lubricant cause glaring faults when finishes cure. Finishes might peel or blister if silicone covers large parts of the surface. Small spots of silicone show up as fisheyes or craters in wood finishes. The finish over the contaminated spot flows away, leaving a visible depression. Lubricating oils can also stain wood and mar the finished product. Hard carnauba paste wax causes fewer problems as a saw table lubricant.

Waxes

• A light coating of plain carnauba wax, buffed to a hard polish, will allow the wood to slide freely over the table surface without transferring wax to the wood. Clear-paste shoe polish or special wax saw lubricants both work well. Some automotive paste waxes contain silicone and cause the same fisheyes and blisters as silicone sprays. Common furniture polishes can also contain silicone that penetrates the existing finish, adding lasting shine but making the old finish difficult to restore or remove. Cleaning a contaminated surface thoroughly with lacquer thinner or turpentine can wash away most of the silicone residue, according to Utah State University Cooperative Extension.

Saw Maintenance

• Keeping your table saw clean and dry prevents most chattering problems. Bare cast iron provides a naturally slick work surface, but it also rusts easily. A faint layer of rust on the table increases friction and puts dark streaks on bare wood. Scrubbing a cast iron table with fine steel wool restores even a pitted surface to good working condition. A rag dampened with turpentine removes the last traces of rust, and a thin coating of silicone-free paste wax protects the table from more oxidation. Clean saw tables make operating the saw much safer, reducing the force needed to move the wood smoothly through the machine.