Rust prevention and general upkeep

[Nick Mazzino]

Hello all,

I set up my first shop in my garage this March. It seems every few weeks or every month I am getting minor surface rust on any cast iron tops (unisaw, jointer, planer, band saw). I have been doing a light wet sanding with 500 grit and mineral spirits then following up with Johnsons paste wax.

Is this just because of the humidity? Is there something different I should be doing instead or in addition? I feel this shouldn't be happening this frequently. I make sure all saw dust and everything is cleaned off my equipment after every use to prevent any moisture from sitting on the cast iron.

Thanks,
Nick

[Matt Day]

You’ve obviously got an unconditioned garage. We’ve had some humid weather for Cleveland this year, hence moisture in the air rusting your cast iron.

Here’s a good article:
https://www.popularwoodworking.com/w...or-woodworkers

[Brian Nguyen]

Keep adding paste wax so that eventually there's enough layers on there to protect better. I also made a Paul Seller's special (rag in tomato can containing 3 in 1 oil) that I'll swipe my hand planes before putting them away. Obviously, using a dehumidifier and/or an A/C unit is even better.

Have to ask whether you're working in a garage while it's raining with the doors open? The moisture in the air from the rain will result in quick flash rusting of exposed CI, guaranteed. I've actually watched this happen to my tools, you can see the rust forming in real time.

[Nick Decker]

Nick, you'll get different opinions on Boeshield T9, but my experience has been excellent. Prior to using it I was relying on paste wax, like you. A couple months ago, I removed it all with mineral spirits and rubbed off all rust spots with Scotchbrite pads, cut to fit a RO sander. Followed that with two coats of T9, allowing each coat to sit overnight then wiping them off. Finally a couple of coats of Johnsons paste wax. I haven't seen one bit of rust since.

FWIW, I'm in Missouri in an unconditioned garage. This morning, there's dew dipping off my windows but no rust on my cast iron.

[Robert Engel]

Nick,

I live in an extremely humid part of the country and I'll tell you what works & doesn't work for me.

If a machine is going to be idle for a while, I give it a light sanding, spray with WD40, and apply a coat of a vegetable based oil. I use Jotoba oil. Do not use a petroleum based oil.

I do use BoeShield, but not as rust preventive, only when I want to slicken up the surface.

Paste wax: I know a lot of guys use paste wax if it works for you ok, but I have had machines rust under paste wax. Personally, I would only use it to slicken up a top. Plus its too much work for me.

Couple other things that will help: keep a fan circulating at night. Keep the shop closed up tight at night. My shop is a converted horse barn -- uninsulated, not climate controlled, but reasonably well sealed up. Since I've started doing this, I rarely ever have rust issues.

Certain times of the year, it will cool down a lot at night and the machines will get cold then if it gets warm I've seen machines actually sweat. When this happens I dry off the water, blow with an air hose and dowse with WD40.

People will say never use WD40 it will interfere with finish, etc. I've never seen that as an issue. Just go light with it.

I keep all my hand tools in a climate controlled room (I call my "Board Room") to me this is the only way to go in my climate.

Lastly, the more you use your machines, the less rust you'll have. Seriously.

Hope this helps!!

[Jacob Mac]

I recently set up my new shop in my garage. Previously, I always worked out of my basement. So dealing with humidity is an entirely new situation for me.

Kansas City has been quite humid this summer, and my new table saw is just streaked with rust. I diligently coated my saw with wax all the time, and it kept rusting. Boeshield T9 stopped the rust. But I didn't figure that out before my saw looks like hell.

My next step is getting a dehumidifier.

[Jim Allen]

FWIW, I live on the coast of Oregon, fairly humid. My workshop is a "finished" 2 car garage, sheetrock, no insulation except the wall that used to be the garage door. I put a couple of electric oil radiators on timers, that turn on (the lowest settings) around 2 a.m. and turn off at noon during the fall, winter and spring. Have had no problems with rust since starting this program.

[Doug Dawson]

Hello all,

I set up my first shop in my garage this March. It seems every few weeks or every month I am getting minor surface rust on any cast iron tops (unisaw, jointer, planer, band saw). I have been doing a light wet sanding with 500 grit and mineral spirits then following up with Johnsons paste wax.

Is this just because of the humidity? Is there something different I should be doing instead or in addition? I feel this shouldn't be happening this frequently. I make sure all saw dust and everything is cleaned off my equipment after every use to prevent any moisture from sitting on the cast iron.

Keeping the relative humidity at 50% or below is IMO just part of the cost of maintaining a workable shop, by whatever means necessary (desert environment, dehumidifier, central air, mini-split etc.)

Cast iron tool surfaces benefit from the occasional application of CRC 3 36, and paste wax generally, much more so than just paste wax alone. But that's just a safety, compared to keeping the shop humidity in check.

[Cary Falk]

I live in WA state. My garage not climate controlled. I just use T9 and paste wax. Works fine for me.

[Charles Lent]

Mat,

Get a good dehumidifier and hook up a drain so it can run 24/7 if it needs to, and keep your garage doors shut as much as possible. Opening a garage door for 1/2 hour will likely take your dehumidifier 24 hours to get the humidity to what it was before opening the door. Keep the dehumidifier set at about 55% and it will keep your tools from rusting, but you will still need to protect them with wax or Boeshield.

My shop has it's own heat pump and it is on most of the time. The shop is a separate building, so I have full control of when the doors get opened and for how long. This year it is much wetter here than it has been in the last 35 years, but my shop isn't having any rust problems. Oh, it's only about 8' above and 60' from a lake too. I just use Johnson's Paste Wax, but the humidity in my shop rarely goes above 55%, and if it does because I opened a door, it goes back down quickly.

Charley

[Lee Schierer]

I would quit using sand paper and switch to scotch brite pads. I remove the rust from mine about twice a year by scrubbing with scotch brite and paste wax. When I get done I wipe it down with a clean cloth and apply a second coat of wax and wipe that down before it completely dries. I live just 7 miles south of Lake Erie so my local conditions are similar to yours.

NOTE: If you cut any treated lumber you want to immediately wipe down the top and rewax it right after you are finished working. The same is true if you were sweating while working.

[Terry Hatfield]

I would quit using sand paper and switch to scotch brite pads. I remove the rust from mine about twice a year by scrubbing with scotch brite and paste wax. When I get done I wipe it down with a clean cloth and apply a second coat of wax and wipe that down before it completely dries. I live just 7 miles south of Lake Erie so my local conditions are similar to yours.

NOTE: If you cut any treated lumber you want to immediately wipe down the top and rewax it right after you are finished working. The same is true if you were sweating while working.

Very good advice. I've occasionally used Scotchbrite pads with Slip-it gel followed by a second coat of Slip-it for many years. Have virtually no rust issues even though I live where it's quite humid on a very regular basis.

[Jacob Mac]

What scotch brite pads are you using?

[Terry Hatfield]

What scotch brite pads are you using?

The ultra fine gray.

https://www.amazon.com/Grey-Scuff-Sc...y+scotch+brite

[Jacob Mac]

Thanks Terry