Protecting cast iron from temperature change rust?

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Forum topic by BTKS posted 12-29-2008 12:39 AM 5290 views 0 times favorited 18 replies Add to Favorites Watch
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1989 posts in 3668 days

12-29-2008 12:39 AM

Topic tags/keywords: question tool maintenance

Need help!!!
Just pulled all my stationary tools out of storage, cleaned and waxed (Johnson’s Floor Wax) all of the exposed cast iron surfaces. Spent hours and hours removing dust, dirt and some light rust prior to waxing. I put at least three buffed out coats of wax on all tools. We had a sudden weather change over the last few days. Temperature went from single digit lows to over 50 one day. One 24 hour period had almost a 40 degree rise in temperature. The tools are in a tin pole barn with insulation. All the doors were closed but the building is far from sealed. Went out to the barn today to find all tools with an even coat of bright red rust. Anywhere an item was left on the cast iron the metal underneath was okay.
Does anyone know how to prevent the rust? Have treated with tools with Bo-Shield prior to storage or long periods on non-use before. Only real problem with Bo-Shield, both cans I’ve purchased in the past have only sprayed out less than a third of the contents before quiting. Don’t know if they clogged or just didn’t have enough propellent.
Any help would be greatly appreciated. Almost lost my lunch when I saw the tools. May have damaged a trash can and a pair of safety glasses in the physical display of frustration following this discovery. Glad my kids were not around to see that one.

-- "Man's ingenuity has outrun his intelligence" (Joseph Wood Krutch)

18 replies so far

View marcb's profile


768 posts in 3877 days

#1 posted 12-29-2008 03:21 AM

The problem that you had I had as well.

The problem with a temperature change that rapid is the cast iron has a huge amount of thermal mass. This means it is resistant to change.

When the temp spiked and all the snow melted the humidity went through the roof. The cast iron on the other hand was still cold and caused condinsation.

With something this ext ream it is not possible to prevent any rust at all from happening. All of the surfaces became doused with water. That water slowely made its way through the layers of wax and started to cause rust.

The only possible solution to a problem like this would be to cover all the surfaces with something like those magnetic pads that they sell. However this will also trap moisture inside and can cause issues as well.

Keeping the air moving might help, I got all the moisture to go away by hitting my fan and turning the heat on for a few hours. Then some 000 Steel wool to knock the rust off and then a layer of T-9 + wax again.

View Karson's profile


35149 posts in 4604 days

#2 posted 12-29-2008 03:27 AM

I’ve had better luck with t-9 also. My shop in NJ was the same way. When spring came it was terrible. I just removed the rust and wished for summer.

Now that I’ve moved to NJ. I don’t seem to have the problem anymore.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia †

View ChuckV's profile


3180 posts in 3731 days

#3 posted 12-29-2008 03:35 AM

I have had the same problems in Massachusetts. There have been days, like today, when the temperature and humidity have suddenly gone wild. My workshop is in an unheated barn.

After the first time, I cleaned up and reapplied wax. Since then, I have been loosely covering the iron surfaces with cardboard – at least when I see that the troublesome weather conditions are on the way. This has stopped the rust and I do not worry about things being too airtight.

-- “Big man, pig man, ha ha, charade you are.” ― R. Waters

View BTKS's profile


1989 posts in 3668 days

#4 posted 12-29-2008 03:52 AM

Thanks for the input!!
Talked to my dad, he has a metal shop down the road. He said his welding table and all steel tools had water dripping off of them.
Think I’m going to try closing up some of the drafts and installing the wood stove I’ve been meaning to put in. I don’t think it will solve the problem but it might help.
Chuck V,
The cardboard sounds good. Do you think wax coated cardboard would be better or worse? Can get all the wax coated I want. In-laws get food shipped in wax boxes for a resteraunt.
Again, thanks, anything to save a hefty investment.

-- "Man's ingenuity has outrun his intelligence" (Joseph Wood Krutch)

View ChuckV's profile


3180 posts in 3731 days

#5 posted 12-29-2008 04:16 AM

I am just using regular corrugated cardboard. I’m not sure if the wax-coated type would work any differently. It just seems that you need something to stop all that warm moist air from directly passing over the ice-cold metal. My first cover on the bandsaw table missed a tiny area near the edge, and there was rust on just that one little spot afterwords.

-- “Big man, pig man, ha ha, charade you are.” ― R. Waters

View archie18's profile


204 posts in 3694 days

#6 posted 12-29-2008 04:25 AM

I also have a pole barn shop. I cover all my major tools with old shower curtains when not in use.

-- Robert in middle TN

View BTKS's profile


1989 posts in 3668 days

#7 posted 12-29-2008 04:59 AM

Are you using the inner curtain or the cloth like outter curtain. I covered a wood stove in plastic one time and nearly ruined it. Ended up having it sand blasted and high temp painted. Turned into a green house. Come to think of it, I had the plastic elevated off the surface just like a green house.
Between the cardboard and curtains, I should have a simple solution. Seems like simple is usually the best.
Thanks guys.

-- "Man's ingenuity has outrun his intelligence" (Joseph Wood Krutch)

View GFYS's profile


711 posts in 3675 days

#8 posted 12-29-2008 05:03 AM

Yes covering the metal is the easiest way to keep condensation from occuring. Wax does stop condensation it only creates a barrier to reduce the effects of oxidization. Keeping the air from circulating along the cold metal surface or eliminating the dewpoint entirely are the only ways to prevent condensation.

View Mark Shymanski's profile

Mark Shymanski

5623 posts in 3916 days

#9 posted 12-29-2008 07:17 AM

Would one of those radiant heaters pointed at the tools warm the surface sufficiently to prevent the condensation?

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

View bbqking's profile


328 posts in 3927 days

#10 posted 12-29-2008 08:26 AM

Don’t treat your tools as flooring. Do not use floor wax. Treat them as you would a nice car and use car wax. I used Turtle Wax all the time I had an open shop in Iowa. Temps from -25 degrees to over 100 degrees every year. Wipe your open surfaces down and rub them out like it was a Mercedes. You will get what you work for. bbqKing.

-- bbqKing, Lawrenceville

View KBC's profile


34 posts in 3665 days

#11 posted 12-29-2008 09:23 AM

I am totally with bbqking.

I just recently worked over my entire shop with a cool product called “The Original Purple Cleaner” from California Custom, then after polishing the surfaces I applied Turtle wax and buffed them out.

We had the same temp. changes here in Illinois and none of the tools had any rust forming( the back door to the shop was not latched down tight and the run off water ran through like a river and still we have had no rust forming)

We also have a radiant heating unit,but the setting is only at 40 degrees ( fuel prices and all) the moisture just couldn’t get through the Turtle wax!

-- Ken, Northern Illinois,

View marcb's profile


768 posts in 3877 days

#12 posted 12-29-2008 05:40 PM


By keeping the shop at a constant 40 degrees you might have kept the tools from being cold enough to cause condensation.

Did you go into the shop on Saturday and check to see if there was a layer of water that formed over all the cast iron or granite (My surface plate was doused)?

View KBC's profile


34 posts in 3665 days

#13 posted 12-29-2008 06:11 PM

Yeah Marcb,I am in the shop every day( since my knee surgery, every day is therapy;the walk to,the standing and moving,the ‘long’ walk back)

I had zero moisture on any of the tools.( I even went back out late last night to look them over,,in fear that rust might be forming …HA)\

Seriously, the Turtle wax (and the Purple polish/cleaner) has been the trick to my shops rust forming problem.

But as I re read your words,,I didn’t check the marble lentil right off the floor,,I am going to check it out today.Lentil

-- Ken, Northern Illinois,

View Bob42's profile


456 posts in 3994 days

#14 posted 12-29-2008 06:27 PM

I am on Long Island and have had the same issues. What has worked very well for me is to clean the surface really well and then use a couple of coats of good liquid Carnauba wax. The liquid gets into the pores or the cast iron and protects it better. I do this every couple of months. This helps the wood slide easier as well. I have also left a small amount of saw dust in the top to absorb any extra moisture. The biggest thing is if you had a way to control the temp in the room. I am going to install this winter a infrared heater to keep me and the tools warm.

-- Bob K. East Northport, NY

View John Gray's profile

John Gray

2370 posts in 4089 days

#15 posted 12-29-2008 07:58 PM

I think the “car wax” is the way to go, it forms a more water-tite seal than Johnson’s. I’d be careful with what is laid on the cast iron, I left a piece of MDF on my tablesaw and it created a large rust spot under it. My 2 cents.

-- Only the Shadow knows....................

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