This week’s question comes from Dave. He writes:
I live in South Carolina where the humidity is way up there. I recently purchased my first cast-iron tool (finally), but I’m noticing surface rust at random. Now, I’ve tried wiping with WD-40 and waxing with a silicone free wax, but neither seem to be helping too much. I don’t do an extraordinary amount of work on my tablesaw, but I want to keep the top looking as good and staying as flat as possible over the years.
And here was my reply:
“Here is what I do for my cast iron tops. Now keep in mind, I am privileged when it comes to rust since I live in the desert. But I used this same system when I lived in S. California and the results were very good. If I see some rust developing, I usually spray the top down with WD-40 and start sanding the surface by hand with 600 grit wet/dry sandpaper ( I use a sanding block). This removes the rust from the surface and makes a nasty smeary paste on the surface. I wipe off the excess. Now I have heard that for some reason, WD-40 can attract moisture to the surface so it doesn’t really protect from rust as much as we think. Not sure how much truth there is in that, but I would rather not take chances. So I clean the top off with either mineral spirits, lacquer thinner, or ethanol. Now the surface is raw and will rust quickly. So now we have a few options for protection. The best protection from rust, hands down, is T9 Boeshield“
“This stuff works great and I can just about guarantee you will not get rust when using this product. The one drawback? It’s not really slippery. In fact, it makes the surface downright sticky. I suggest applying a decent coat, rubbing it in, and letting it sit overnight. The next day, buff the surface with a clean cloth. Once it no longer feels real sticky, get your favorite wax out. Apply several coats. Any silicone-free wax is good. One of my favorites is a spray wax called Glidecote.”
“Then about once a month (you might need to do it more), I spray the surface and reapply the wax. I also like to use Renaissance Wax when I am out of GlideCote. Hopefully this will prove to be an effective treatment for you.”