Stopping Rust in the workshop?

Having moved house about 2 months ago, the brick garage with a flat roof looked like being an improvement on the 10 x 8 shed at the old house.
Now any of my big lumps of cast iron are frequently wringing wet with condensation and any bare metal parts such as flywheel rims and lathe or milling machine beds are rusting before my eyes.
Does anyone have any ideas on how to stop this. I am thinking about lining the roof and walls with plasterboard or plywood and filling the cavity between the board and brick wall with rockwool type insulation. Has anyone else tried this and found it successful, also any ideas on a long term background type of heating that can be left on at night for most of the winter without it costing a fortune.
I know that I can coat everything in oil or grease until the spring but this not always convenient when I want to nip in to the workshop and use the lathe, when I get an hour to spare I don't want to spend 20 minutes cleaning the grease off before I start and the same again reapplying before I can go back in the house.
Many thanks - Paul.
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I've just had the same problem. You need to find out where the damp is getting in, and cure to problem. It may be that the roof is leaking, poor window frames, or a whole host of possibilities. Have a good look round. Damp feeling wood is a good sign that you are close to the problem.
Lining the ceiling and walls is not likely to fix the problem, and rock wool will absorb water and may make the problem worse.
I haven't found my problem area yet, although I suspect that it is water collecting between the small gap between my garage and my neighbours.
As an immediate, but temporary solution, I have purchased a de-humidifier from a DIY shop, cost 100, and this has worked very well. It has dried out the garage, stopping the surface rust that was appearing, and is taking a lot of water out of the air. A full container a day !! At 350 Watts, it's cheaper to run than a heater, and more effective.
The good news is that a good spray of WD40 and all the surface rust is wiping off.
Hope that helps
Cheers Mark

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Paul swindell wrote in message ...

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I presume you are not doing anything silly like keeping the car in the garage too! This will import water vapour.
A garage is very unlikely to have a damp proof course and this time of year you could be getting damp by this route. As an experiment you could put a old newspaper on the floor with a sheet of polythene on top just to see how much is coming in by this route. If this turns out to be the main source then consider epoxy coating the floor. this will also pay dividends in helping keep the dust down when sweeping up.This dust is abrasive and wrecks machine slideways.
Good Luck
Bob
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On Fri, 31 Dec 2004 18:47:30 GMT, "Bob Minchin"

Tsk tsk! Surely you're not suggesting that any engineer worth his salt would consider wasting valuable workshop space by cluttering it up with cars? (other than the one being dismantled/reassembled, of course...)
Regards, Tony
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On Fri, 31 Dec 2004 17:32:01 GMT, "Paul swindell"
Paul,

I use the back eight feet of my 16 x 8 single brick garage for a workshop. It has a flat roofing felt covered roof.
I plated the walls with plasterboard on 2 x 2 battens and put a polythene sheet vapour barrier behind the plasterboard. I also plated the ceiling with plasterboard. The floor is concrete and I laid 2 x 2 battens on the floor on top of damp proof strip, then laid a tongue and grooved floor. This gives insulation from the concrete and also provides a much kinder surface to stand on. I built a partition wall across the garage so that the workshop area is self contained.
The workshop is heated with a small 2Kw electric convector heater with a thermostatic control. When I'm not in the workshop, the thermostat is set to about 55F which is above the dew point where condensation will form on machinery and tools. When I come into the workshop, the thermostat is turned up to about 70F.
I've had this setup for about ten years and I have never had any rusting on the lathe, or any other steel materials. I still provide for some ventilation since I use a drape in the doorway in the partition wall which is not air-tight, and does allow for some circulation with the remainder of the garage, which in itself has ventilation thanks to a not very well fitting up and over door :-)
JIm.
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Homebase and B&Q now sell a range of dehumidifiers.

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Do they consume heat, as you claimed before?
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I now have a double glazed and well insulated workshop but for many years made do with an unheated shed. I threw an old blanket plus an old candle-wick bedspread over the lathe thus forming a kind of tent. On the floor underneath the lathe was a caged inspection lamp with 40 Watt bulb. It served well enough.
--
Mike Hopkins
CSME <http://goto/cheltsme>
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This is a recurrent problem reported in this news group and the causes and solutions put forward show a general lack of understanding of the subject which can be both simple and complex (sorry about that, it is Hogmanay) Anyway my advice is to think first of ventilation. Dutch Barns had plenty of ventilation, the seed corn, hay and machinery stored therein kept dry. People in the past knew a thing or two.
A coating of oil is helpful once you have provided adequate ventilation but don't waste your money on WD40 for this purpose. Two stroke oil diluted with white spirit is a better bet, the white spirit evaporates leaving a goodly coating of oil.
Here in the Outer Hebrides we have plenty of dampness in a salt laden atmosphere but we also have plenty of wind to help with ventilation. My own machinery and tools in the workshop are rust free.
There are, or were when I was investigating such problems, British Standards on the subject of dampness and condensation in houses. The Building Research Establishment, if it exists post Thatcher, could also provide help.
Donald, Isle of South UIst
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writes

You want to go easy on the neaps. ;^)
--
Nigel

When the only tools you have are a Bridgeport, a CNC Taig Mill, a Colchester
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wrote:
Donald,

But what you don't have, from memory, is the possibility of very cold weather spells followed by temperature rises through the dew point, where condensation forms on cold metal surfaces. Providing some form of heating to keep the ambient temperature in the workshop above the dew point prevents this happening.
But I agree that some form of ventilation is also required.
Jim.
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Why does my car outside on the drive get a build up of condensation (and hoar frost in cold weather) when it hasn't been raining? It's as well, or better ventilated, than your description below.

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Basic physics letting you down again Gareth?
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Ventilation certainly makes a big difference, especially where there is damp penetrating from outside. My workshop is in a cellar room - built in 1900 so the DPC is bricks laid directly on sandy soil. The damp doesn't just rise, it goes sideways and down as well ;-)
Fixing the problem involved 2 approaches:
first, reduce damp penetration by painting the walls with an Epoxy 2-part paint (a water based epoxy that will cure on damp surfaces).
second, install forced air ventilation. I used a unit that Wickes used to sell - two centrifugal fans, one to expel air to the outside, the other to draw fresh air in. Both air flows go through a heat exchanger to use the (warm) exhaust air to warm the incoming cold air. Has a built in drain to lose the inevitable condensate in the exchanger.
The result is a very dry cellar - no rust on tools etc. and no "musty" cellar smell either, unless you switch off the ventilation system.
Regards, Tony
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If you have single course brickwork, then the damp drives through the mortar and you a problem. I'm now regretting not having had a cavity wall when I had the garage re-built.
What I have found is that heating the garage makes the problem worse - One cold night I spent a couple of hours with a fan heater on and the following morning the amount of rust that had formed on the cast iron I had been machining was amazing. The heater drives loads of moisture into the air, switch the heating off and the air chills very quickly.
Too keep the lathe chuck "safe" I either wrap it up and put it in its box or more usually stick the box over the chuck (including grease proof wrapper) in situ.
I am thinking about applying silicone masonry sealer in the summer to reduce the amount of moisture getting in. After that I think the next step is a full vapour barrier as described in the other posts.
I did think about a de-humidifier, but I feel that's just avoiding the root cause and can't be a permanent solution.
Steve
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At a previous house we lived at the garage was single brick with piers, much like Steves. Because of space restrictions I had to share this with a large freezer, After that - no condensation problems, I put this down to the fact that the slight amount of heat given off was enough to keep above the dew point.
Worst mistake I ever made was to fit a wall mounted propane heater supplied from and external bottle. Total disaster, switched on, went into the house whist it warmed up and came out 1/2 later to see pools of water everywhere, mill table, lathe bed and two pools collected at the base of the welding bottles.
I didn't realise that a 112lb bottle of propane will release 112 lbs of water into the air.
I currently use a large wood burning stove and have no problems with rust. I have approximately 15 to 17 tons of machinery / steel stock indoors that has to be heated so the temp differences can be extreme but the stove copes OK. I don't oil up and so far the odd wet days I used to get when the temperature took a sharp turn and left me with rust problems have long gone.
Downside is I get a fine layer of dust / ash from this stove but it's always dry so I ignore it.if I was to dust sheet down at night this would disappear but it's a working shop, crap and all <g> -- Regards,
John Stevenson Nottingham, England.
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On Sat, 01 Jan 2005 12:19:50 +0000, John Stevenson

I second the comments on the value of good insulation and low level heat. Johns wood burning stove solution is particularly good because it both exits hot moisture laden air through the chimney and draws in colder relatively dry input air.
Simpler solutions are sometimes possible.
Moisture can ONLY condense on a surface if that surface is colder than the air in contact with it. This is worst case with the surrounding air saturated with water - 100% humidity,
A typical problem is a large mass of cast iron that has been cooled down by the low temperature of the night air followed by the warm humid air of the following morning. Warm air is less dense than cold air*. In the stagnant air of an unoccupied workshop, the cold mass near ground level will set up convection currents that eventually bring much of the total air volume of the workshop in passing contact with the cold mass - each time depositing its evil bit of condensation.
It's not the small bit of stagnant air around the surface that's the problem - it's the fact that the convection currents produced by the temperature gradients make it possible for a large fraction the water carried in the workshop air volume to be deposited on the cold mass.
Because of this it's possible to make a substantial difference by simply blocking the path of the convection currents. Most of my kit is in a relatively benign workshop environment but a large floor standing circular saw with a cast iron table top has to live at the end of the garage in which I park my car.
Convection currents are roughly blocked by a large plastic sheet which is draped over the whole machine. When I first installed it several years ago I "polished" the top with a coat of simoniz car wax but apart from that it's had no further treatment and it's still rust free!
I've probably been pretty lucky because it's a very old machine with a well seasoned cast iron top. The top is also less massive than the average lathe. Nevertheless the difference is substantial - quite a lot of rusting is evident on unprotected mild steel stocks originally lightly greased and stored in the same environment.
It's not a method that I would rely on for the sole protection of a newly bought expensive machine but it's a simple and effective second line of defence. The thing to remember is that the main convective flow is vertically downwards so, as long as your plastic sheet deflects this, you're winning.
Jim
* Water vapour is less dense than air so the larger fraction of water in the warm humid air increases the density differential.
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On Sun, 2 Jan 2005 18:39:29 +0000 (UTC), snipped-for-privacy@yahoo.com wrote:

We have stored machinery up at a friend's farm (what would we do without friends!) and each has a piece of truck grade pvc/nylon sheeting over it. That has kept things nice over the past year or so without any heating at all. The building is ventilated (broken windows etc) but the roof is dry.
The stuff that has to sit outdoors is usually multi-wrapped in various sheets but the PVC/Nylon that is used for truck sheets etc is the last one on and is totally waterproof. The polypropylene woven blue tarps are next to useless, especially after a decent bit of wind (natural, not bean-induced!)
Peter
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In the old workshop - wood construction with lining inside and double glazing - I used an electric oil-filled radiator with a doctored thermostat to keep the temperature above the dew point.
Six years ago I built a new workshop, similar construction, but during a visit to the local surplus stores I noticed a dehumidifier for 25 GBP. All that appeared to be wrong with it was a cracked plastic front panel. I bought it and it works! For six years I have had it running continuously and that is all I do. No rust, just gets a bit on the cold side during the winter, but a wooly pullover solves that problem. The water it collects is stored in a large plastic drum, in case I can find a use for it, until it gets full and it also supplies water for the wife's steam iron.
The old workshop I turned into the railway room and treated it to a new dehumidifier at around 100 GBP from B&Q. It's identical to the 'broken' one and that works.
Steve wrote:

snip
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.

I also use a dehumidifier with equal success. The only problem is that it relies on ambient temperature for defrosting, so when the temperature is below 5 the ice doesn't melt, in fact it accumulates into a large block that subsequently takes a day to melt. I fitted a hose to carry the melt water out of the building to save having to empty the tank.
Cliff Coggin Kent UK
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