Advice for Rust Prevention- Question of the Week

March 20, 2007 | Filed Under Blog, Question of the Week 

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 doesnt 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? Its 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 Top Cote.”

“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 Top Cote. Hopefully this will prove to be an effective treatment for you.”

Comments

9 Responses to “Advice for Rust Prevention- Question of the Week”

  1. Scott on March 20th, 2007 10:13 pm

    Marc,

    Will the same treatment regimen work for cast iron planes? I wrapped one of mine in my work gloves for the trip from California to Germany when I moved here (I’m in the military) and I now have a Lie Nielson block plane with some “character.” Needless to say, I would like to get it back to its original glory and keep it that way.

  2. thewoodwhisperer on March 20th, 2007 10:23 pm

    Hey Scott. That treatment would work great on a plane. When removing the rust though, i would probably progress through to the highest grit paper I could find (probably 2000), since looks count for something on a LN plane.
    I actually treat all of my hand tools with T-9 to prevent rust. And if you are traveling, put on a heavy coat and just put it away. Dont wipe off the excess. You will be very pleased with the results.

  3. Scott on March 21st, 2007 9:26 am

    Thanks, Marc! I actually left all of my stationary power tools in storage in Monterey, CA. I smeared a heavy coat of cosmoline on all of the bare metal surfaces, and I’m hoping for the best when I see them again after 3 years in a non-climate-controlled warehouse in the salt air.

  4. Stan Armstrong on March 21st, 2007 10:13 am

    Given the general advice to avoid using WD-40 near wood due to finishing problems, I am puzzled about why you use it at all here. Why not just dry sand, or if you insist on making mud, use a different lubricant?

  5. thewoodwhisperer on March 21st, 2007 5:20 pm

    The main reason not to dry sand is the performance of the sandpaper. The rust will quickly clog the paper without lubricant. And you can use just about anything other than water as a lubricant. Mineral spirits comes to mind. I use WD-40 because it doesnt evaporate and its pretty cheap compared to the higher quality lubricants.

  6. Jim on March 21st, 2007 9:10 pm

    WD40 is not an ideal product to clean the cast iron. The liquid portion of the product never fully evaporates and thus traps corrosive mineral deposits between the porous cast iron surface and a thin coating of the WD40 liquid. The surface should be cleaned with mineral spirits and 600 grit wet/dry paper. Next, wipe the mineral spirits from the surface. Clean the surface with acetone. The acetone dries almost on contact and does not allow any moisture to remain on the surface. Since the cast iron is porous it is important to heat the surface so that the wax is able to flow into the minute pores of the metal. Heat a 12 x 12″ section with a propane torch or a heat lamp until it gets hot enough to liquefy the wax on contact. Be sure not to stand directly over the wax to avoid breathing in the vaporized material. Repeat this procedure until the entire surface has received a coating of wax. Allow the surface to cool for 20 minutes and then buff off any hazy residue. This should keep away rust for a reasonable amount of time but more frequent waxing may be required depending on your own pattern of usage. Typically, the best method of fending off rust on a cast iron deck is to use it every day as the constant burnishing of materials moving across the surface creates a natural polishing action. It still needs to be waxed but usually only once a month during the most humid of summer months.

  7. Mitchell on March 23rd, 2007 6:43 am

    I live in Toronto, Canada – in a condo. My tool cabinet lives on my balcony 12 months a year. While most Americans think that we ski up here in July, and feed our polar bears in August, the reality here is that our weather goes through the same cycles as Buffalo or Boston. Ok, maybe a little more extreme, but close. I do woodworking almost 12 months a year on that balcony, usually on the tool cabinet (luckily, I share a full shop at a friend’s home). To protect the tools year round I spray them all down with WD-40 four times a year. It is a bit of a pain in the butt to have to wipe down the tools with a rag soaked in Varsol every time I want to use it, and respray it before putting it away, but not one of my tools have a spot of rust on them. I think (he says cockily) that it is all in the maintenance. Any good tool worth having is a piece of art, both in design, and in execution. It should be treated accordingly, even if it is locked up in a cabinet, outside, in -10 degrees weather.

  8. Kyle Barton on March 29th, 2007 2:30 pm

    Corrosion X also works very well and is a lubricant. It was developed for Military/Industrial applications, is used widely in the boating world, and is just now coming to the attention of the woodworking world. I am not related to the company, just an avid boater and woodworker. For more information see this link: http://www.corrosionx.com/hd.html

  9. Al on February 23rd, 2008 4:51 pm

    Well, I don’t know if anyone comes back this far to read these since I am about a year behind. However, I learned a long time ago to use a gun bluing kit to protect my cast iron surfaces. You can get them at any sporting goods stores that sell firearms. Make sure that all of your surface rust has been removed and follow the directions on the kit on prepping the surface and bluing it. Once dried I put on a couple coats of paste wax and polished it. This protected the surface for many years. I had to occasionally re wax it. It was also slippery so the wok piece would slide easily

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