Condensation in workshops

[MikeParticipant @mike89748]

I see that earlier in this thread I mentioned I was using Superdry dessicant packs. They work well, but if used in drawers or boxes must be checked very regularly. Once they get saturated the water drips out, and causes the rust they were preventing when new and active.

Like Cyril, I live by the sea in the North of Scotland, but don’t have the luxury of a permanent electric supply to my workshop – power comes from a small petrol generator which is only run while I am working. Hence, I can’t use a dehumidifier.

On the subject of WD40, I have recently been using Tesco Maintenance Spray, which seems to be pretty much the same stuff but less than half the price. It being summer (?) I can’t report at first hand on its rust prevention qualities, but it does prevent a build-up of aluminium on tool tips, and provides a good finish, too.

[Sub MandrelParticipant @submandrel]

Harold Hall makes a few comments about condensation in his workshop book. As he points out its warm air picking up moisture (e.g. from damp walls) then coming in contact with cold machinery that is the big problem. That’s why insulation that stops rapid temperature changes is the best solution.

 

The cotton cloth is in no-way inferior to plastic sheet. The latter can trap moisture next to the machine when the air is warm and damp, so it condenses when the temperature falls suddenly.

 

Cotton doesn’t act as a barrier to water vapour, it’s true, but it’s a good insulator so it reduces those temperature changes and being breathable it doesn’t trap moisture (which is why cotton is comfy in both cold and hot weather).

 

I used a monthly spray of WD40 to keep my gear OK for 7months or more, stored in a garage.

 

Neil

[PatParticipant @pat]

Hi folks

 

A very heavy cotton sheet acts not only as an insulating layer but more importantly acts as a trap for moisture. The cotton sheet needs to be heavy twill or multiple layers of cotton although I have friends who use woollen blankets. The important thing appears to be to avoid synthetic fibre but there are some fancy materials that claim to have wicking properties that might work as well cotton but on the other hand these are many times more expensive. Heavy cotton machine covers have a long history and I for one have found it a satisfactory method of keeping machinery free from rust but the root causes of the damp need to be addressed.

 

IMOH the use of an impermeable barrier cocooning the machinery will make matters worse rather than better as the machine will collect condensate from the enclosed air unless desiccant is added or a source of heat.

 

May I suggest an experiment under your local conditions. Loosely wrapping iron nails which have been cleaned in both plastic sheet and cotton . Further comparisons with the nails coated in your favourite rest preventing mix and leave them for a few weeks close to your machinery and look at the surface at the end of the experiment for each sample and then select the appropriate cover for your machines.

 

I thought plastic sheet was a good idea some 40 years ago when it first became available but was warned off my an old hand who had a thing about rubber ground sheets and tarpaulins being used as machine covers. Did the experiment to prove him wrong and have used untreated cotton covers with a light rust preventative spray to the machine not the cover. I use Rocol Ultraglide as it does not need to be wiped off – usual disclaimer about commercial connections for protection on a day to day basis with WD40 reserved for longer term storage.

 

Try the test and see – Regards – Pat

 

 

Edited By Pat on 10/07/2011 11:54:45

[Keith Wardill 1Participant @keithwardill1]

Sorry to bring this subject up again. I have read this thread (and others), and have become a little puzzled at some of the (apparently) conflicting advice. My workshop is single story, brick built, concrete floor, with fibreglass lining behind wood-panelled walls. There is no ceiling, simply wood lining panels nailed under the rafters, and the gap between lining and tiles filled with fibreglass wool. I have no heating of any kind. (not much gets done in winter )

I have several machine tools (lathes, a mill, pillar drill, hacksaw, etc, plus a large selection of handtools. The metal lathes and mill normally have an old curtain thrown over them when not in use – this was not to inhibit moisture, but to reduce the amount of dust collecting on the machines (very dusty here in summer – eastern Europe).

Autumn is usually very wet, followed by a winter of mixed snow (~100cms) and rain, with temperatures down to more than -15 degs C, before it starts to get warmer for summer, which can reach 40 degrees C.

When we first came here, I was worried about tool corrosion, but never really got around to doing anything about it – the machines tools sometimes get oiled during maintenance. Despite this, I have never suffered any corrosion at all on these tools.

At some times, I would appear to have the warm-cold-condensation conditions perfect for corrosion yet none appears, (for which I am duly grateful), but it does make me wonder why some people seem to get it badly, yet others have no problems (but I do have 'rusty hands' – another problem )

 

Edited By wotsit on 08/01/2013 19:36:44

[SteamshyParticipant @steamshy]

Think air conditioning would go down well in my shed, just came from it as the temp is 34c Andy

[colin hawesParticipant @colinhawes85982]

Greenhouse bubblewrap insulation under the plastic roof of my workshop has made a vast difference. Colin

[BazyleParticipant @bazyle]

I think conditions in central Europe can be a bit different because the moisture is frozen out of the air by the extra low temperatures whereas in the UK we are always very damp.

Plastic sheets sweat and then the water runs down the inside to hit the machine at the contact points delivering significant amounts of water that can wash away the oil at that point. Natural fibres actually absorb the moisture into the fibre whereas synthetic ones can only hold it by capilliary action between individual fibres so it is still able to touch the metal directly at contact points. Obviously the natural fibre can become saturated and loses its effectiveness especially if covered by a plastic sheet as a belt and braces approach.

Remember your vapour barrier. When installing insulation modern practice advises a waterproof barrier 100% coverage on the hot side of the insulation using plastic sheet or foil. Otherwise moisture vapourised on the warm side migrates through the insulation and condenses halfway through causing mildew or woodrot. Even a small hole will allow vapour migration and a localised problem. This also ensures no draughts to bring in moist air so a dehumidifier can quickly produce a safe atmoswhere.

Just before xmas I got a cheapo shed for storage. I have temporarily blocked most gaps and installed a dehumidifier while I am in the process of cutting up 2 in expanded poly insulation. Initially I intended to fill the 1 in framework with insulation before the 2in layer . However I found the wood and joints so poruous that I am leaving the 1 in gap and removing some air seal despite teh loss of insulation so that it can breathe naturally otherwise it will rot. Inside the insulation will be a plastic sheet with all joints taped so that he only moist air ingress path is the door.

40, 60 and 120 watt tube heaters are readily available on the auction site but check the range of prices which can be double for teh same item.

[FMESParticipant @fmes]

My workshop was purchased as a 22' x 16' concrete sectional unit with two 3' doors, one at each end, and two small double glazed UPVC windows, erected on a 6" thick reinforced and vapour barriered concrete base.

The panels had 2" x 2" timber battens bonded to the bolted sections which then formed a 3" bay into which a further vapour barrier and 3" of rockwool insulation, the battens were then covered with 19mm shuttering ply.

The roof was treated to the same but the ply was only 10mm.

I run a standard household dehumidifier with a consumption of around 350 watts on the 'night rate' and this on its own maintains a general temperature of about 10 – 12 deg C even when its frosty outside, relative humidity stays at around 40 – 55%.

The only treatment I do to the machines is a spray round of a propriety penetration spray after cleaning.

I do have air-con installed but is only required for short periods.

Lofty

Edited By Lofty76 on 09/01/2013 19:30:42

[mechman48Participant @mechman48]

On a similar tack I have posted a write up in the thread .. 'Workshop heating' .. describing my attempts to insulate & heat my garage conversion which so far have proved most satisfactory.. but there is always room for improvement!

Cheers & happy new year to all.

George

[Ian S CParticipant @iansc]

Not too practical today, this is from an artical in vol 1 no 3 March 1898, To Preserve models from Rust, with Dr J. Bradbury Winter. He used small glass trays (bird feeders), 3" long x 1 1/2" wide x 1 1/4" deep, in these he put pure, undiluted sulphuric acid, about 1/8" deep, the acid absorbs water, and when it got to 1" deep, he emptyed it, and started over again. He used this in the glass cabnet that his locomotive Como was in, in his study.

He does give a warning that one must be carefulnot to spill the acid, or get it on clothes, or your fingers. Ian S C

[nigel jones 5Participant @nigeljones5]

My metal items rust rapidly if left in the workshop (strangely the brass ones dont). I bought a second hand dehumidifier from ebay, new at B&Q they are £100, it removes gallons of water if you leave it running and nothing ever rusts!! Very worthwhile. Remember that warming the room doesnt remove moisture, it meerly changes state and moves around!

[Sub MandrelParticipant @submandrel]

Excellent advice from Dr Winter. Personally, I find it advantageous to get one of the footmen to change the acid.

Neil

[nigel jones 5Participant @nigeljones5]

It can also be used to strip the silver goblets prior to recoating them…

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