Condensation....I never knew you

[craigs]

What do you chaps use to battle winter condensation?

My current arrangement is a humidity sensor connected to smartthings which auto triggers a dehumidifier above 65% and turns it off at 50% as a result...no rust

This works, but am i overly complicating something ?

 

[Phil Pascoe]

Humidity here is low atm, it's only 89%. If I run a dehumidifier it's on perpetually. I only had surface rust when I had a pot belly stove. 65% is a figment of the imagination here - my sister exported antique furniture to Auckland and it didn't shrink or crack - and Auckland has to be one of the most humid places in the world. It was 95% when we were last there - I commented on it and she said we should have come when it was high.

 

[CHJ]

As long as you arrange for any metal surfaces to be warmer than the ambient air temperature you will not get condensation on them to cause rusting even in high humidity.

Same applies to any surface really but metal tools and machines are usually the critical ones.
Keep tools such as planes etc. in a cupboard, heat saws, lathes etc. with low wattage heating 24/7.

Cover large equipment such as saws, pillar drills, lathes with fabric sheeting to retain heat and reduce moist air from making contact.

A search of the forum should turn up a host of back threads on the subject.

 

[porker]

The key to humidity is to understand it. This will help solve issues as CHJ states, for workshops the key is to keep the metal surfaces warmer than ambient. I have a metal lathe and mill, so a lot of cast iron I want to keep rust free so I cover with sheets and it works a treat. I have seen various solutions over the years such as running a low wattage bulb or heating element just to keep the temperature in a tool box a little warmer.

The other issue is that when people state humidity what they are really referring to is relative humidity. This is really important as the temperature has a huge effect on this value. 100% RH at 10C is 53% RH at 20C for the same amount of water vapour in the air. Often this means raising the temperature to combat the condensation or better still having good insulation.

Interesting issue with Phil's pot belly stove as I run two woodburners in my house and they tend to produce a very dry heat which I like for my old house but makes SWMBO's eyes dry sometimes. I made the mistake of running a gas space heater in my old (large) workshop and that added a lot of moisture to the air.

 

[Phil Pascoe]

The heat itself is dry, but when the workshop cools quickly the tools stay warm longer and attract condensation. I have a multi fuel indoors, but of course the bungalow never gets that cold and there's little humid through draught.

 

[porker]

Yes, good point. If you can't keep it heated it is a problem. I used to live in Cornwall and you get your share of damp compared to South East.

 

[pcb1962]

My current arrangement is a humidity sensor connected to smartthings which auto triggers a dehumidifier above 65% and turns it off at 50% as a result...no rust

This works, but am i overly complicating something ?

You could complicate it further by only running the dehumidifier if the ambient temperature is at or below the dewpoint. Above the dewpoint it doesn't matter what the humidity is because the water won't condense on your tools.

 

[CHJ]

The heat itself is dry, but when the workshop cools quickly the tools stay warm longer and attract condensation. I have a multi fuel indoors, but of course the bungalow never gets that cold and there's little humid through draught.

Are you really sure about that, water condenses out onto a colder surface I think you have got your reasoning about face.

Your previous comment about your sister took furniture to Auckland with higher humidity and it did not split or crack is to be expected, expose wood to higher air moisture levels and it will absorb the moisture and swell.

Take the same item to Morocco, Southern Spain, Egypt from Cornwall and there is a big risk it will shrink and or crack, even standing it alongside a radiator or in front of a south facing window is asking for damage.

 

[porker]

I agree. It's actually because the tools are made of metal and a good conductor (ie poor insulator) they cool quicker and hence the condensation forms on them

 

[craigs]

You could complicate it further by only running the dehumidifier if the ambient temperature is at or below the dewpoint. Above the dewpoint it doesn't matter what the humidity is because the water won't condense on your tools.

oh that goes beyond my basic skills and probably needs coding....temp i can do and i have a heater that keeps the garage above 5c overnight, but dew point i dont have an option for....le sigh

i dont have a condensation issue yet though...

 

[Benchwayze]

I never suffer from condensation in my workshop. I don't have any heating in there at all, and have no need to worry about tools going rusty. My garagre/workshop is integral with my house, and this this is one of the reasons why my shop is so dry. This is helped by by the the fact that at the open over metal door faces due South and and whatever the weather it catches the heat and acts like a convector. I cannot imagine any other reason for my shop being so dry. Only in very damp winters do I have any problem with light trust in the vicinity of the door, which has the usual disadvantage of gaps around the door. I have tried various methods to cancel out this problem, but none of them have had much effect; in the end and I just do not store metal tools too close to the door.

John

 

[Vinn]

When I bought my Record Power Bandsaw, the rep from Record said to cover it with a blanket. I'm now intending to do something like that. I have a large workshop that is difficult to dehumidify. In your experience/knowledge what would you guys recommend from:

• Cotton dustsheet
• Cotton dustsheet with plastic liner
• Plastic dustsheet
• Blanket

Just thinking about buying something from Screwfix. Plastic is cheaper but would it not work as well, I wonder?

Cheers

 

[CHJ]

Don't use plastic, not a good insulator, use an old bed sheet, old mattress cover, old child's cot blanket.

Anything that retains motor and bearing warmth when used keeps them rust free under covers when not in use.
If machines rarely used a low wattage heater in the base works wonders, in the 1960's I had 7watt car sidelight bulbs running off a transformer in my garage workshop tool cupboard to keep tools rust free. Worked even though a very wet vehicle was often parked in there.

Lathe accessories, chucks etc. not getting the benefit of radiant sun heat coming through the shed south facing windows are in a set of old kitchen draws heated 24/7 with a 7watt long life bulb, all metal items taken out always feel warm compared with the machines.

 

[Vinn]

Don't use plastic, not a good insulator, use an old bed sheet, old mattress cover, old child's cot blanket.

Anything that retains motor and bearing warmth when used keeps them rust free under covers when not in use.
...[SNIP]...

Thanks for the advice

 

[CaptainBarnacles]

I had a heartbreaking moment yesterday when I went into the workshop for the first time in a few days only to find my new bandsaw and lathe covered in rust. I have used camelia oil and renaissance wax on both machines and it clearly wasn't up to the task. My workshop is pretty big, stone-built, very draughty, unheated, uninsulated and unfortunately (at least in the winter months anyway) lies at the bottom of a steep-sided valley with a stream running right by it. Obviously I am up against it.

I have read this thread with great interest and will be digging through old threads for further info on how to combat rust.

Regarding my machines, I wiped off the surface moisture, rubbed down the bandsaw table and lathe bed with a Scotchbrite pad which thankfully removed almost all of the rust leaving a pretty decent finish. I then applied a product that I got from Yandles called Pocket-Rocket which I believe is a penetrating oil with PTFE. It stinks and I'd prefer to use something less offensive but in a hurry it was the first thing I thought would do the job. I have been back in today and there's no sign of any rust. I think I'll be looking around for some old bedsheets this afternoon.

 

[pcb1962]

I have used camelia oil and renaissance wax on both machines and it clearly wasn't up to the task.

A good coat of Liberon wax will both keep the rust off your tables and help the wood to slide across them.

 

[RGIvy]

One of the BP technical service engineers explained to me that all I needed in order to deal with most of the rust is to have my workshop 1 degree above ambient. I have a plastic shed inside a barn where I store most of my tools, and all I did was keep an old incandescent light bulb on which seemed to do the trick - no rust. I didn't even bother with a heater.

 

[mikej460]

Vintage tractor owners use 50/50 old engine oil and diesel and it works a treat on my farm machinery. For workshop machinery and tools though I now use ACF-50 which is excellent stuff.

 

[Sheptonphil]

In my last workshop which was poorly insulated and always felt damp in winter, I’d cover the whole of my Jet 3520 lathe and cast iron table of the band saw and sander with flannelette bed sheet, I spray the beds with GT85 and drape the sheeet over. I’m curious now to see if condensation on the iron is going to be an issue in my new build Insulated workshop. It’s not heated at night, only when I’m in there, but I do have a frost stat setting if I need to set it.

 

[Paul Narramore]

I have a brick built two storey workshop to house three motorcycles, and engineering lathe and an industrial pillar drill. The other day I went out there and everything was dripping wet. I got out my demidifier, an Igenix IG9800 I bought secondhand last year, and when switched on the display showed a temperature of 15C and a relative humidity of 92%. I switched it on and a few hours later is showed 50% and the condensation had gone. I now have it on a timer so it switches on for 12hrs a day, 7pm to 7am, and the tank gathers about 20 litres of water in 24hrs. No heater needed so far. Nothing is rusty as I wipe an oily rag over every bare metal. I shall fit an 1/2" hose to the humidifier to run to a drain, to avoid the daily tank emptying.