preventing rust on CI surfaces

[Demps]

I've got a concrete floor stand alone shop. No heat on here in June. We got a cold spell this week and high humidity + rain. In one day I got light surface rust on several cast iron tops. They were well waxed one month back.
I seem to recall a discussion here about machine covers, HTC makes some apparently good, and inexpensive ones. What's the wisdom here for prevention?? I guess a dehumidifier is another option...

[bobs64ford352]

I get lots of fluctuations up this way and the CI doesn't like it. I used to use paste wax, but it didn't seem to work for me. I ended up picking up a woodworking magazine that had a rust preventer shoot out. CRC 3-36 was one of the top products and I've been using it since, with good results. A gallon jug was $36 from amazon. I've been using it for over two years now and still have at least half a gallon left.


Bob

[Steve N]

What kind of building are you in? Pole barns with metal uninsulated roofs can make their own weather. I've seen what looked like rain inside of one with a solid roof. If your building is tight, and insulated you can look at the topcoat. I use Boesheild T9 followed by a coat of cheap paste wax. I use a buffer as seen below with a mop top to buff the wax out after rubbing it down as best I can by hand.

[Demps]

Building is stick built, tight construction. Likely the problem is due the big weather fluctuations.

[Cooler]

Put a 15 watt bulb under the cast iron surface. As long as the cast iron is warmer than that surrounding areas condensation will not occur. The problem is on a warm humid night the cast iron is cooler and the moisture condenses on the surface like an iced tea in the summer.

The light bulb, if left on all the time will provide that localized heat.

http://a.abcnews.com/images/US/GTY_iced_...x9_992.jpg

[rwe2156]

Rust remover (I like the Boeshield brand) + scotchbrite, followed by a rinse with brake cleaner, then coat with Boeshield.

I too, am not a big fan of paste wax.

[barnowl]

Demps said:

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I've got a concrete floor stand alone shop. No heat on here in June. We got a cold spell this week and high humidity + rain. In one day I got light surface rust on several cast iron tops. They were well waxed one month back.
I seem to recall a discussion here about machine covers, HTC makes some apparently good, and inexpensive ones. What's the wisdom here for prevention?? I guess a dehumidifier is another option...

---

Blankets. Old, new, it makes no difference.

If the cold damp air cannot condense on the CI, it cannot rust it.

And it can't condense when there's a blanket on it to keep it from even touching it.

[Jeremy s]

Air conditioner. You can thank me later.

[YSU65]

My shop is 26 x 30, concrete floor, storage overhead. Walls and ceilings are insulated with R19. I only have a double door entry, no overhead garage door. You will get condensation - and rust - on your cast iron surfaces when warm moist air will come in contact with a cool surface. I also wax all CI surfaces with paste wax.

With that intro, I cannot open my shop up to outside air, ie open doors and windows, because the shop is cooler than outside air and I will get condensation with resulting rust. Happened once. My friend with a shop about two miles from mine opens his overhead door all the time and he has more rust than I do. Now we do live in upstate NY where we can get some humid days. If you lived in a very dry place, it may not be a major problem.

Note: I will save the detailed discussion on relative humidity and partial pressure for those poor folks stranded on some isolated island with nothing better to do....Tom

[Redman]

Cast iron rusts. You can slow it down with various things but cast iron rusts. Let it get a patina, it'll look better. Cast iron rusts, even when liberally coated with oil.