# Keeping dry atmostphere in workshop



## Hickorystick (10 Dec 2014)

Hi
My almost completed workshop has insulation in the ceiling joists (flat roof) and plasterboard over.
The walls have OSB panelling. Ive noticed over the last week when the temperature has been really cold outside that the workshop has obviously been very cold also and after being in there for a little while noticed there was a slight film of condensation on some of the metal machine casings.
My obvious worry is that if this is constantly repeated throughout the winter I will end up with a film of rust on bare metal surfaces.
Anyone know how this can be overcome ? The workshop is not heated although I had toyed with the idea of a pot belly stove but that would only be lit when I was in it.
Is there something like a dehumidifier.... or something that works like Silca Gel ?
Anyone out there with a similar issue and solved it ?

Thanks
Phil


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## woodpig (10 Dec 2014)

I've had two garage workshops that were damp. The first one leaked air quite a bit which many say should help to keep condensation down, it didn't. The second only leaked air at the up and over door and was better. I now have a wooden cabin which has sealed windows and door with just a few tiny air gaps near the roof and all is well so far. I have bought an oil filled radiator to keep the damp at bay but haven't needed to use it so far. From what others have said unless you heat the space an electric dehumidifier won't work. You could try some of those crystal types. B & Q sell them along with tubs of replacement crystals. We've used them in damp cupboards before and it's surprising how much water they can collect.


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## CHJ (10 Dec 2014)

If you can provide a small amount of heat to your machine castings with something like a low wattage bulb or vivarium matt low down under them and cover the machines with a throw then as long as the metal is a degree or so above the ambient air then condensation will not settle on them.

More elaborate methods fix low wattage, low voltage supplied resistors to the machine beds and physically supply a heat source directly, but you need some electrical knowledge to do it safely.

My chuck/accessories cabinet has a 7watt bulb in it and all steel taken out feels warm compared with stuff out in the shop.

The steel window frames are the overnight cold sink in my shop and they accumulate the condensation rather than the lathes and tools in rack.


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## Phil Pascoe (10 Dec 2014)

If you fit a pot belly you'll cause more problems than you solve. I didn't have any rust at all until I used one.


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## John15 (10 Dec 2014)

I seem to have very little problem with dampness in my small unheated (except when I'm in there) workshop. It is an all timber structure with double cladding, insulation and a plywood lining. I have removed the window, primarily for security but it also helps with keeping the place dry, and as an extra precaution against rust to my machine beds I periodically apply Liberon Lubricating Wax.

John


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## [email protected] (10 Dec 2014)

to keep a workshop dry you need a dehumidifier - end of! They only cease to work if temperature drops to around freezing as I understand it, so stick an oil filled rad in there as well when its frosty.....


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## Hemsby (10 Dec 2014)

Humidity problems are all too common :x . My workshop has no insulation at all and I used to suffer bad problems with surface rust.

I purchased an EcoAir ECO DD322FW Desiccant Classic Dehumidifier that works down to 1 deg C and since using it the rust problem has completely stopped =D> . The only heating I use and only very occasionally for a short while before I start work is a fan heater (not while there is dust about, due to fire risk) other than that it is the Dehumidifier.

Although it only works down to 1 deg the workshop, even in the coldest winter the internal temperature has never dropped below 4 deg anyway.

Keith


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## [email protected] (10 Dec 2014)

yes, dehumidifiers are amazingly effective. You can pulll out 5litres of water from the air every 24 hours - water that would otherwise have settled into the fabric and content of the building. Also because it removes moisture it makes the air seem warmer. And they cost no more than a fridge to run....


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## n0legs (11 Dec 2014)

I have a large commercial grade dehumidifier and have no issues with condensation or damp.
It's better than heating the workshop constantly to keep away the damp. It's on constantly and "plumbed in" so there's no buckets or tanks to empty.


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## DennisCA (11 Dec 2014)

As I see it, dehumidifcation is too difficult where it gets cold like here and I don't keep my shop at a temperature high enough to make it an effective proposition.

My plan is to have an air inlet and a heater to warm the incoming air. Heating the air increases its potential to hold moisture and it will absorb moisture from the colder air in your your shop and on surfaces. Then vent it via another vent somewhere else (opposite side of room perhaps, facing eastwards is preferable, or so I've been told), you can just have an heating element infront of the incoming air and rely on self-draught, or use a hot air fan.

Right now I just have an air space heater and the garage port isn't fully sealed so that is what has to allow for air movement. Not optimal but no rust issues in my shop. I plan to use a solar panel later to heat air to help warm and dehumidify air.

My garage is probably better insulated than most your houses are though...


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## Jacob (11 Dec 2014)

You can have passive dehumidification with single glazing fitted to allow condensation to drain off to the outside e.g. a gap at the bottom of the panes over a cill with a bevel, or moisture collection in a channel drained off to the outside.
It works very well on all my windows - you really become aware of how much water is extracted if the weep holes block and it accumulates instead.


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## Yetty (11 Dec 2014)

I've used an electric desiccant type dehumidifier in my workshop for years. Beforehand, the air was damp, steel rusted, and I was worried about the timber movement due to excess moisture. 

These dehumidifiers work well at lower temperatures, and the heat produced is very welcome in the winter. A cheap hygrometer is useful for checking what is happening, as there are times when the dehumidifier isnt needed.

I don't operate the dehumidifier v24/7, just when a project is running or am preparing some timber before a project starts. If a project is underway, then often I run the dehumidifier mainly when the workshop is vacant, especially at night.

A nice side effect is that the workshop temperature tends to feel a few degrees warmer than it actual is.


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## doorframe (11 Dec 2014)

I keep my workshop heated 24/7. 1 fan heater, and a 12" fan on slow to help move the air around. Yes, it does cost money to run, but it's always warm enough to work in just a t-shirt, and it's worth it to me to have it comfortable in the evenings when I get home from work and all through the weekends.

Edit to add, it's a single skin wooden structure, and it's bone dry with no rust in the last 13 yrs since I built it.


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## siggy_7 (11 Dec 2014)

See here for a description of fitting electric heaters to metal machines: tis-the-season-of-rust-and-mellow-fruitfulness-t55942.html I'm in the process of doing this at the moment.


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## tomlt (11 Dec 2014)

Look up rubydry dehumidifier, had mine 2yrs, works great in my 5.5m x 7.5m unheated garage, uses silica based technology rather than condensing so works down to low single figures no problem, also puts out a little heat, enough to keep my uninsulated building 4deg c above ambient. 

Tom.


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## wallace (12 Dec 2014)

For the past few years I have been battling the rust monster on my machines I've tried most sprays to prevent rust but still had problems. A couple of months ago I got a cheap dehumidifier from a car boot. I have noticed a big difference to my machine surfaces. I have it set low and collect about 4lts a week


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## DennisCA (12 Dec 2014)

Oh yes one of my future plans is to use a home built solar catcher to warm and dehumidify the shop for free. Probably building it next year.


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## Jacob (12 Dec 2014)

DennisCA":14kqxwr1 said:


> Oh yes one of my future plans is to use a home built solar catcher to warm and dehumidify the shop for free. Probably building it next year.


It's called a "window". 
Single glazed and drained if you want it to dehumidify. South facing for heat. The best design is the double sash - water drains off between the meeting rails and at the bottom of the bottom sash. But it doesn't have to be that complicated.


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## KevM (17 Dec 2014)

I'm toying with the idea of a dehumidifier, probably of the dessicant variety because of the background heat they produce and their ability to work to lower temperatures. There's a recent review of a bunch on the Practical Boat Owner website; an interesting snippet jumped off the page:


> Desiccant dehumidifiers ... require operation in air free from solvents. Solvents (from resin or varnish) can affect the desiccant.



From what I've read all the dessicant humidifiers seem to share a common technology in their zeolite dessicant disc, so it's probably worth bearing in mind if you use solvent based finishes.


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## Benchwayze (18 Dec 2014)

I must be lucky. I never had a problem with condensation in the workshop.

However, I use a single-garage, integral with the house, so I don't need much heating. Also the metal, up and over door, is due-south facing. Only on the coldest days does it feel chilly to the touch, and I can work in there with the door open all the year round. So I assume the door acts as a convector, whenever it gets the slightest sun on it. It gets darned hot in the summer mind! (hammer)


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## DennisCA (1 Jan 2015)

Jacob":13foqrtf said:


> DennisCA":13foqrtf said:
> 
> 
> > Oh yes one of my future plans is to use a home built solar catcher to warm and dehumidify the shop for free. Probably building it next year.
> ...



A single glaze window. I think they stopped using those in the late 1800s in Finland. The amount of heat lost through that would be atrocious.

A proper solar catcher is insulated on all sides and preferably a vacuum is made between the transparent layer and the metal to minimize heat losses there. And the black surface is corrugated for maximum efficiency of catching the sun.


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## woodfarmer (1 Jan 2015)

I use oil on my machines... roughing out bowls from green wood causes 99% of eh dampness in the lathe shed.


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## YBT4 (6 Jan 2015)

My shop is 10x4m , 150 slab with radon barier, blocks on the flat wiith 50mm kingspan on the walls and pitched roof, I have never had any dampness so far five yrs on, the external walls are not plastered even, I put it down to the radion in the slab and breathable membrane under the steel cladding


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## blackrodd (6 Jan 2015)

One of my friends bought himself a ML7R,recently, which is a solid piece of iron and I believe this latest addition has tipped the balance of cold steel mass in his workshop, as for the first year in 25 years of the workshop history, the metal is sweating and going rusty. 
He's taken to cleaning every part up and waxing with Bri-wax, and no problems re occuring so far.
(I think he's using dark oak, do you think it makes a difference)??
He also said that the Startrite planer thicknesser was easier to use and feed.
Regards Rodders


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## Benchwayze (6 Jan 2015)

DennisCA":3ryrw8bm said:


> Jacob":3ryrw8bm said:
> 
> 
> > DennisCA":3ryrw8bm said:
> ...




If that be the case Dennis, then I don't know why my shop is so dry. The metal door is white, and it has the normal gaps around it that any up and over door has. Fact is it still gets hot in summer, and reasonably warm in winter after an hour or so of sunshine. 

I don't know what condensation is in my shop.


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## Claymore (6 Jan 2015)

In my old workshop (converted garage) the metal door was white and it was always cold/damp in winter, i changed the colour to very dark green and amazingly on bright winter days it was lovely and warm and no damp  the sun warms dark colours hence reason Arabs have white cars to deflect the sun (black cars warm up more in the sun) simple solution and cost nowt.
My new workshop is great all doors are upvc white and fully glazed....... also has a 8ft d/g window, the office is insulated with plasterboard but the main room just has painted breeze blocks and insulated metal roof.... its always cosy as its south facing and gets sun all day.


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## DennisCA (7 Jan 2015)

Benchwayze":31w8r8wd said:


> If that be the case Dennis, then I don't know why my shop is so dry. The metal door is white, and it has the normal gaps around it that any up and over door has. Fact is it still gets hot in summer, and reasonably warm in winter after an hour or so of sunshine.
> 
> I don't know what condensation is in my shop.



I don't know what you think I said in my earlier post, but I didn't say it wouldn't work. Only that it would be terribly ineffective and inappropriate for this climate. I was so shocked about the single glaze thing I had to go and google about british construction standards afterwards to read up on it. In subtropical climates like the UK perhaps you can get away with things like single glazed windows without making your power bill go through the roof.


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## Benchwayze (8 Jan 2015)

Well Dennis, in the 1950s we didn't have a choice. Double glazing was unheard of, central heating was for the rich, carpets also were out of our price range. In fact I remember making a pine and perforated zinc food-safe', at school, to store the meat outside, because we didn't have a fridge. 

On the other hand, I could go to the pictures, buy a bag of sweets to eat in the cinema, buy a fold of chips on the way home, afford a bus ride, and still have change from a sixpenny piece!

well, okay... The first paragraph was true, the second paragraph might be stretching it a bit. :mrgreen: :mrgreen: :mrgreen:


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## Random Orbital Bob (8 Jan 2015)

There is a cheap and cheerful solution that works. My workshop is part of a large garage with up and over doors. Two of its walls are part of the house and two are outside facing, one of which is the big door side. It does get a bit rusty on the cast iron but the draft from the gaps in the doors helps a little. I just (about every 3 months) use a green kitchen pan scourer to clean the cast iron tables (bandsaw, tablesaw, planar/thicknesser) and then coat it with cheap old paste wax from Tesco with a soft cloth. If you want to achieve the same thing but spend a lot more money, use that T-9 Boeshield (didn't Boeing develop it for the aircraft industry???) which I understand is pretty good.

To be fair I've had no problems with the cheap wax. The trick is you have to do it in time...sort of October ish or whenever the ambient temp starts to drop and keep it up, especially after heavy use.

I do my bandsaw every time I've used it to cut heavy green timber.


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## Random Orbital Bob (8 Jan 2015)

There y' go....have page of blurb....I think I'm going to be sick....allergic to marketing speak......


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## Random Orbital Bob (8 Jan 2015)

And this is the cheap old rubbish I get from Tesco that does the job just as well but without the blurb or the need for a mortgage!


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## Hickorystick (8 Jan 2015)

excellent - I'm going to try this... and as an added bonus I'll have the nicest lavender smelling machines in the neighbourhood !


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## Random Orbital Bob (8 Jan 2015)

There you are y'see...now can T-9 botty-shield claim they smell of Roses?? I don't think so


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## Jacob (9 Jan 2015)

DennisCA":36t7b756 said:


> Jacob":36t7b756 said:
> 
> 
> > DennisCA":36t7b756 said:
> ...


Double or triple glazed will still work as a dehumidifier if designed properly with some way for water to run off. In winter you add curtains / shutters etc. All it requires is for the window to be the coldest surface, which they usually are anyway. 
One way or another there has to be energy exchange.


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## blackrodd (9 Jan 2015)

Lavender polish, Can't stand the stuff!
I had to work for my pocket money, when it was too wet or cold outside, feeding our chickens, collect eggs, work in the garden etc, I was known to be sent polishing furniture, using the jolly old lavender flavour.
Rodders


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## Random Orbital Bob (9 Jan 2015)

It reminds me of my old Mum, God rest her soul......she loved the stuff....whole house reeked of lavender.


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## blackrodd (10 Jan 2015)

Random Orbital Bob":2chnefau said:


> It reminds me of my old Mum, God rest her soul......she loved the stuff....whole house reeked of lavender.




Yeah, me too! Reminds me of picking, gooseberries, raspberries etc, etc, and the dreaded blackcurrents, about 10.000 to the pound, and bottling everything for the winter larder with mr Kilners jars. 
The house we lived in then, still had the pigsty at the bottom of the garden..
regards rodders


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## Random Orbital Bob (10 Jan 2015)

don't forget the elderflower and elderberry wine.....demijohns blipping and bubbling for months on end before the most evil smelling potion emerged from the bottle several years later


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## Phil Pascoe (10 Jan 2015)

I had a gallon of banana blow on me when the lock clogged - excrement, you should have seen the ceiling. It was one of thirty three separate gallons I had going in the kitchen at the time.


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## blackrodd (10 Jan 2015)

Random Orbital Bob":264ze00t said:


> don't forget the elderflower and elderberry wine.....demijohns blipping and bubbling for months on end before the most evil smelling potion emerged from the bottle several years later




My gran made the elder flower, so smooth, and elderberry wine, lovely in the winter as a hot toddy with the hot poker 
There was a lot to being a housewife and mum then, Rodders


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## wellywood (10 Jan 2015)

Aah! The good old days when beer was tuppence a loaf.

Back to subject. There is really only one solution to condensation and that is to heat and/or ventilate.
Godzone has quite a damp climate and the windows in our home used to stream with condensation until we installed a positive pressure ventilation system. It only requires a small fan (about the cost of running a light bulb) to draw air from the roof space and over-pressure the inside space which drives the moisture-laden air out.
I realise this might not be practical in this case (no ceiling space in the shed) but, married with a heat source, it's the only way to cure the problem. Either that or running a dehumidifier which might be expensive.


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## DennisCA (12 Jan 2015)

^^^^
That's the opposite of what we do here, we use underpressure in the house because the last thing you want is hot air being pushed out through the houses climate shell, which then causes the hot moist indoor air to meet the cold fiberglass or rockwool insulation and condense in it. Over time your insulation is destroyed and you'll be working two jobs just to afford the electricity bill in winter. Sure there is a vapor barrier but it's not perfect and gets damaged over time (installing nails and such for picture frames and whatnot). So we aim for a slight underpressure. Better to let a little cool air in than destroy the insulation. My house is so airtight air enters mostly through our machine ventilation which has a built in heat exchanger so that the exiting air's heat isn't wasted.

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Well it dropped to -10 yesterday and today it's -15 celcius, I was in the shop last night and didn't run the heater, just me being there and using the machines kept things around 4-5C, but today things had dropped to -3C inside the shop around 18:00, when I came back with an oil element to heat the shop. I don't think that's so bad considering the big garage port is a heat losing... thingy...

I got this now because it's 1 phase so it doesn't steal a valuable 3ph outlet and I can leave it on all the time with it's thermostat for temperature maintenance. The fan is much more effective since it heats the air directly and also blows it around but I don't dare leave it unattended.


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## Jacob (12 Jan 2015)

wellywood":10qd7kha said:


> Aah! The good old days when beer was tuppence a loaf.
> 
> Back to subject. There is really only one solution to condensation and that is to heat and/or ventilate.
> Godzone has quite a damp climate and the windows in our home used to stream with condensation until we installed a positive pressure ventilation system. It only requires a small fan (about the cost of running a light bulb) to draw air from the roof space and over-pressure the inside space which drives the moisture-laden air out.
> I realise this might not be practical in this case (no ceiling space in the shed) but, married with a heat source, it's the only way to cure the problem. Either that or running a dehumidifier which might be expensive.


The other way is to treat the windows as de-humidifiers - accept condensation but allow it to drain off to the outside.
It works really well. Condensation on the windows but not anywhere else. The only prob is dust on the wet parts of the window - it sticks and they need a bit more cleaning.


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## custard (12 Jan 2015)

[email protected]":1s8ot9mg said:


> to keep a workshop dry you need a dehumidifier - end of! They only cease to work if temperature drops to around freezing as I understand it, so stick an oil filled rad in there as well when its frosty.....



I bought a new dehumidifier for my boat recently and was told it's a different design that functions just as well in cold conditions as in warm. Unfortunately I'll just have to take their word for it as it's piped overboard so I've no idea how much water is actually extracted. However you're right about traditional dehumidifiers, the one in my workshop needs emptying very day in summer, but only once every four days in winter.


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## Hemsby (12 Jan 2015)

There are all sorts of suggestions how to maintain a good constant level of humidity in a workshop, but a dehumidifier is a simple no nonsense and most importantly a controllable way of doing the job. 

I would suggest that most members spent considerable amounts of money on a workshop & equipment. For me to have a rust free environment and a stable stock of timber the running cost of a dehumidifier seems insignificant in the great scheme of things.

As I mentioned in my earlier post on the subject I use a Desiccant dehumidifier which works down to 1 deg, but even in the recent freezing conditions my non insulated workshop has never dropped below 4 deg anyway.

Mine can collect the 10 litre max most days so I connected it to a permanent discharge pipe for convenience.

Humidity generally is less in cold/freezing weather than warm/hot.


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