Question about rust

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I'm glad somebody else had this problem.. I thought I was going nuts. Why only the jointer and not the other tools? BTW, I read the same article and in it they claim Empire's Topsaver was the best rust removal and second best preventative. I got some, used it to clean up the badly rusted used jointer I had purchased after sanding the excess rust away. It worked so well I sprayed what little I had left on the TS, small bottle...doesn't go far, and with little effort it removed the stains with ease. 8 days later with high humidity nary a sign of rust. I might mention I did apply wax afterwards. Good stuff...
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On Sun, 25 Jan 2004 03:39:30 GMT, "Mike in Mystic"

1. Water is the most common catalyst of rust. 2. Rust requires oxygen. 2. Moisture moves away from warmer temperatures and toward cooler temperatures.
You can use these facts to protect your equipment. Keep your shop as dry as possible. Keep your iron surfaces protected with some kind of coating. Place a 4 watt lightbulb inside or under your cast iron tables, just enough heat to make the temperature higher than the surrounding area. Burning kerosene, propane, wood, or combustion of any kind in the shop produces moisture--Infrared lamps or electric heat is better at keeping your shop dry.
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snipped-for-privacy@hotmail.com says...

a small shop in an unheated outbuilding and I live where the humidity is low in summer and high in winter. So the tools sit unused for a lot of the winter in a cold and damp shop.
The only time I've seen rust on either the jointer or the tablesaw was right after I bought them. And, to be truthful, the time I set a bunch of green wood on the tablesaw for 24 hours or more :-).
When I first saw the rust shortly after purchase, I started waxing the tops with Johnsons Floor Wax. I do it two or three times a year. It works, and I suspect any similar wax would also work.
If you use your cast iron tools every day, you might have to wax more often. I'm not sure about that, as I suspect the wax gets down into the pores of the cast iron and resists rubbing off. So that's just a guess.
--
Where ARE those Iraqi WMDs?

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You may want to warm up the shop SLOWER next time, the cast iron is heating up slower than the air and the temp difference is causign the condensation.
As to why it is being seen the most on the jointer is a puzzle
John
On Sun, 25 Jan 2004 03:39:30 GMT, "Mike in Mystic"

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Mike,
Tom Watson had an interesting post on this not too long ago, wherein he reported on using shellac as a coating that was more effective than all the standard ones at preventing rust. Have a look at it at:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=ln6lsv4mktceq9isav7i6ov27d7ki4rvd9%404ax.com&rnum=1&prev=/groups%3Fq%3Dgroup:rec.woodworking%2Binsubject:shellac%2Bauthor:tom%2Bauthor:watson%26hl%3Den%26lr%3D%26ie%3DUTF-8%26scoring%3Dd%26selm%3Dln6lsv4mktceq9isav7i6ov27d7ki4rvd9%25404ax.com%26rnum%3D1
Sorry for the long link. If you have trouble with it, just look up an advanced GS using the delimiters: recent date/rec.woodworking/subject: shellac/author: tom watson.
Regards, H.

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On Sun, 25 Jan 2004 03:39:30 GMT, "Mike in Mystic"

I've been trying to beat the rust problem for years and finally feel like I have it under control. Here's a few of the things I think I've learned.
Atmospheric Moisture is a byproduct of combustion. The RH of the shop air may not change that much as you run the heater, because the increasingly warm air can handle the increasing amount of moisture generated by the combustion process, but the absolute moisture content is driven way up.
The RH of the shop air is not the problem. It is the RH of the microclimate right next to the cast iron surfaces that is the problem. The cast iron, having a great deal of thermal mass, cannot react to temperature changes fast enough and stays cold enough so that, with the temperature/humidity level rising quickly in the shop's air - the cast winds up being below the dew point - and rust begins to form.
The jointer, having greater thermal mass than the other machinery, due to the thickness of the castings, shows the rust first.
The solution that I finally came to was to put my kero fired salamander on a timed thermostat. The thermostat is a plug in style from Grainger and the timer is one of those cheap things that you can use to turn lights on and off with.
I set the timer to turn the heater on to about fifty degrees for an hour or so before I go out to the shop. This allows the shop to warm up more gradually and thus avoid the air becoming too warm/moist too quickly. I had to fool around with where to put the thermostat in relation to where the hot air shot out of the salamander. If you put it entirely out of the warm air stream it will call for heat for too long and the air will heat too quickly. It's better to have the thermostat close enough to the air stream that the heater cycles on and off more than you would want for normal operation. When you come into the shop in the morning you can move the thermostat to a more normal position.
The other thing that I found out about rust is that wax doesn't work in my shop and neither does TopCote. Boeshield will work if applied heavy and left to dry without wiping but the result is too waxy for a daily use tool.
A few months ago I decided to try dewaxed shellac. It works better than anything I've ever tried. It goes on fast. There's no concern about introducing bad stuff onto the wood surface. It's cheap. It's easy to reapply. It provides a slick surface. . .(and it makes the tools look great).
Good luck.
(tom - rustless at last)
Thomas J. Watson-Cabinetmaker (ret) Real Email is: tjwatson1ATcomcastDOTnet Website: http://home.comcast.net/~tjwatson1
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The reason you get the 'preferential condensation' is that the jointer isn't warming up _as_fast_ as the other stuff.
This can occur for several reasons:
1) mass of the metal, relative to exposed areas. The more mass, per unit of 'exposed area', the _slower_ it warms up. The larger the temperature differential, the more condensation. (all else being equal)
2) _location_ in the space, a) poor air circulation around it, means slower warming. b) absent something to 'keep the air stirred up', temperatures are not likely to be uniform throughout the space.
3) The heater is a non-trivial source of humidity. *anything* that burns hydrocarbons is such a source. The reason:      C(many)H(some) + O(2) => CO(2) + H(2)O
Propane is "C(3)H(8)", thus you get 4 cu. ft. of water vapor for every cu. ft. of propane you burn. Or about 35 fl. oz of water, per pound of propane.
4) Humidity _will_ migrate into colder air, faster than heat does. The 'why' is involved. but the result is that the colder spots tend to have higher relative humidity, which contributes to the condensation.

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