The everlasting condensation problem.

[artie]

I have been reading up the old threads about condensation problems and see I am not alone.

My workshop is about 10m by 14m divided into two 7m by 10m one of which I work in mostly, the other not so much.

4m high at the back and 4.5 at the front.

It is single block walls, concrete ,unpainted floor and corrugated tin roof. It is fairly draughty, which I think may help some.

It is unheated.

I have been working in it for 14 years :shock: , but decided recently to do something about it.

Reading the other threads, there seems to be a consensus that ventilation is key.

Considering that condensation only occurs maybe a dozen nights per winter, Perhaps hooking up a fan would be the most cost effective solution.

Does anyone have any idea how much air I would need to move to keep it dry.?

 

[SammyQ]

10x7x4 metres? Sheesh, 280 cubic metres = bloomin' big fan. Condensation happens when machines are cooler than incoming air. If you have gaps/vents all round the roof, chances are on a winter's day, machines are cooler than air - especially after sun comes up and warms the atmosphere - so you get bucket loads of condensation.

Let your fingers do a chase round the the Net for '9fingers resistors stuck to machine undersides' tip. Bob ses he has used this since Noah borrowed his big tree saw and his machines are pristine in an unheated (but also insulated) workshop. I think he has a sticky about this over on Wood Haven.

Sam

 

[artie]

The roof is my main problem. I did an experiment today, there is about 3 inches of snow on the roof, so a cert to get lots of condensation, so I went out first thing and opened all the windows and the 2 ten ft roller doors and came back in for brekky.

Then we had a power cut, so didn't go out again till after lunch. It was bloddy cold but barely a drip. I could see condensation on the roof but not nearly as much as usual.

So this would re enforce the more air or air circulation argument.

 

[busy builder]

Insulate you roof, 2" kingspan should do it, with ventilation. When I do roofs with metal profile, I always put 12mm ply down first then felt or similar then profile sheets on top, never see much condensation doing it that way. But you also need ventilation.

 

[Brad Awl]

I'm plagued with condensation problems on my lathe bed. I left the eaves open on my shed to allow air circulation but it doesn't seem to help. Am considering closing them in and running a de-humidifier.

 

[Myfordman]

The 9fingered write up is here on this forum. It should help with Brad Awls situation. It will not sort out the OP issue which needs serious work on the structure to fix.

 

[ayuce]

I don't know much about U.K.'s weather conditions but rules of physics should be same here and there. Probably you already know about it, but a quick reminder on why condensation occurs and how to control them.

Temperature changes within the shop, its not constant. Places near walls, windows probably colder, big iron machines heats up and cools down slower than surrounding. Any surface below dew point temperature in the shop will get some condensation.

Dewpoint is depends on absolute humidity, amount of water in the air. Hygrometers measures relative humidity, means how much the air saturated to water. The two is related but not the same. If you heat up the air relative humidity drops, since as air heats up its water holding capability increases. But absolute humidity doesn't change, since you do not remove any water from air.

Anyway , to avoid condensation

- You had to increase surface temperature of things ( machine, walls etc.) above dew point temperature by increasing isolation, heating up and similar.

- Or you had to lower dew point temperature = decrease absolute humidity level in your shop, by removing water from the air. You can increase air circulation ( it depens on the weather conditions, might not work always but a must), or you can use dehumidifier.

- If there is continous water vapour sources a water leakage, open water source like full buckets, bathtubes, wet chothes etc. its better to remove them.



Regards
Ahmet

 

[Brad Awl]

If there is continous water vapour sources a water leakage, open water source like full buckets, bathtubes, wet chothes etc. its better to remove them.

There is a small stream at the end of the garden a several feet from the back of the shed which is probably the main culprit for moisture laden air........ removing it however may be a challenge :mrgreen:

 

[memzey]

I don't know much about U.K.'s weather conditions but rules of physics should be same here and there. Probably you already know about it, but a quick reminder on why condensation occurs and how to control them.

Temperature changes within the shop, its not constant. Places near walls, windows probably colder, big iron machines heats up and cools down slower than surrounding. Any surface below dew point temperature in the shop will get some condensation.

Dewpoint is depends on absolute humidity, amount of water in the air. Hygrometers measures relative humidity, means how much the air saturated to water. The two is related but not the same. If you heat up the air relative humidity drops, since as air heats up its water holding capability increases. But absolute humidity doesn't change, since you do not remove any water from air.

Anyway , to avoid condensation

- You had to increase surface temperature of things ( machine, walls etc.) above dew point temperature by increasing isolation, heating up and similar.

- Or you had to lower dew point temperature = decrease absolute humidity level in your shop, by removing water from the air. You can increase air circulation ( it depens on the weather conditions, might not work always but a must), or you can use dehumidifier.

- If there is continous water vapour sources a water leakage, open water source like full buckets, bathtubes, wet chothes etc. its better to remove them.



Regards
Ahmet

That is very well explained Ahmet. Thank you very much (or should that be tesekurler kardes?)

 

[shed9]

Dehumidifier will do the job, seal up the obvious draughts and vent the output to an outside drain. Been doing that myself for over two years now in a 15x3.5m shop. Just had to replace a machine in the last few days but considering it ran constantly for over two years I don't feel I have a complaint. I've had no rust / condensation issues and the environment is more suited for the end product we are all working with, i.e. wood - seems this aspect is often forgotten about in wood shops in terms of climate control.

With your situation I would run one per area, just leave them on automatic low settings.

Make sure you get the desiccant type as this will operate at much lower temperatures and even heat the room at the same time.

 

[ayuce]

If there is continous water vapour sources a water leakage, open water source like full buckets, bathtubes, wet chothes etc. its better to remove them.

There is a small stream at the end of the garden a several feet from the back of the shed which is probably the main culprit for moisture laden air........ removing it however may be a challenge :mrgreen:

So you have to go with other two options. It's safer to use dehumidifier. Most of dehumidifiers have a hygrostat, turns on/off by checking the moisture. A nice side effect of dehumidifier, it heats up environment slightly. Woods in you shop also would be more stable.

I woudn't leave an electric heater unattended in a shop even it have thermostat. Wood and wood dust is everywhere. I've read some folks are attaching resistors to the machines, using them as heating elements. If you do it be careful about power adaptor type, ratings, quality and voltage levels. Can get electrocuted, power adaptor could burn if its poor quality or not properly choosen..


@memzey not at all ( birsey degil kardes )

Regards
Ahmet

 

[Myfordman]

One of the best sources of power adaptors for heater resistors are lighting transformers. Designed for long life and continuous use and are sold in huge volumes and so are very reasonably priced which more approvals than you usually see on other power supplies.
Output voltage is usually 12 volts and they need to be loaded to at least half their maximum rating to make sure the electronics start up properly.

Here is an example http://www.toolstation.com/shop/Lightin ... mer/p55497

60 watts is more than enough for most machines and cost is £3.28

As an example 5 resistor attached to the machine connected in parallel gives 3 ohms and 48 watts of heating.

 

[ayuce]

One of the best sources of power adaptors for heater resistors are lighting transformers. Designed for long life and continuous use and are sold in huge volumes and so are very reasonably priced which more approvals than you usually see on other power supplies.
Output voltage is usually 12 volts and they need to be loaded to at least half their maximum rating to make sure the electronics start up properly.

Here is an example
......

60 watts is more than enough for most machines and cost is £3.28

As an example 5 resistor attached to the machine connected in parallel gives 3 ohms and 48 watts of heating.

It says "electronic" and short circuit protection etc. All implies its not a simple transformer but a SMPS. It would be better if i can see the photo of inside or schematic. I know about electronic, mass market, component and manufacturing costs.
4.2€ retail price for a 60w 12v power source is "too good".

Regards
Ahmet

 

[Jacob]

.......
Anyway , to avoid condensation

- You had to increase surface temperature of things ( machine, walls etc.) above dew point temperature by increasing isolation, heating up and similar.

- Or you had to lower dew point temperature = decrease absolute humidity level in your shop, by removing water from the air. You can increase air circulation ( it depens on the weather conditions, might not work always but a must), or you can use dehumidifier.

- If there is continous water vapour sources a water leakage, open water source like full buckets, bathtubes, wet chothes etc. its better to remove them.



Regards
Ahmet

Just a reminder - the passive dehumidifier option works well, i.e. a window with weep holes and condensation collection channels which will drain condensate to the outside. It may also increase temperature by solar gain.
Velux skylights are worth a look - they are fitted on a gradient and the bottom edge of the glass panel rests on a moulded gasket with weep channels. A Velux will work as a de-humidifier.

 

[condeesteso]

I'm with shed9 - been running a dehumidifier overnights (timer midnight to 7am) for several years. Absolutely worth every penny. Machine was about £200 I recall (smaller shop than OP mind) and costs coppers a night. I remove about 5 litres a week, maybe 8 days in winter - mine is less effective as temp drops.
But the order I think is [1] insulation and ventilation (forced if necessary, i.e small fan somewhere); [2] extract moisture; [3] heat input.
As shed says, let's not forget we work wood, so dry is vital.

 

[Phil Pascoe]

Seconds &Co are worth a look if/when you insulate.

 

[Myfordman]

One of the best sources of power adaptors for heater resistors are lighting transformers. Designed for long life and continuous use and are sold in huge volumes and so are very reasonably priced which more approvals than you usually see on other power supplies.
Output voltage is usually 12 volts and they need to be loaded to at least half their maximum rating to make sure the electronics start up properly.

Here is an example
......

60 watts is more than enough for most machines and cost is £3.28

As an example 5 resistor attached to the machine connected in parallel gives 3 ohms and 48 watts of heating.

It says "electronic" and short circuit protection etc. All implies its not a simple transformer but a SMPS. It would be better if i can see the photo of inside or schematic. I know about electronic, mass market, component and manufacturing costs.
4.2€ retail price for a 60w 12v power source is "too good".

Regards
Ahmet

Not sure what you are say about a price being too good?
Yes they are a type of SMPS a technology that is highly mature now and reliable if designed properly.
I don't know of any iron based lighting transformers in mainstream us in UK - things maybe different in Turkey.
I don't have a schematic for the 60 w unit but I did take some photos a few years back







I hope this is of interest albeit a little off topic

 

[ayuce]

i`m an electronics engineer having 20 years of experience in r&d. ( i love my fingers and woodworking, us style not safe for my fingers this is why i ve searched and found a uk based forum) . Me and my teams designs goes into 15 millions home from south africa to norway, us to china every year. Pretty sure millions home in UK have our designs. So belive technology is not so much different in UK and Turkey.

i havent designed linear supply for ages for the systems we made, just smps. The pictures you send gives some hint but of course didn t enough for a professional verdict, cant say its looking great.

EU safety regulations (read as beab, vde aprovals) puts some seroious restrictions on the design and components used. And our internal standarts even higher than eu's. Especially if a user can touch output terminals. To cut costs sometimes unsuitable competents are used in cheap designs. For example instead of triple insulated smps transformer, normal one. Or ordinart high voltage caps instead of Y1/Y2 type. it works but not safe for eu standpoint.

i know the price structure this is why i said too cheap. similar psu is 2 pounds in Turkey , i ve ordered to one of team engineers buy one and examine it. Perhaps will see a suprise but dont think so.

sorry for typos i m on mobile

 

[artie]

Seconds &Co are worth a look if/when you insulate.

I had a look at their site, unfortunately the don't deliver my corner of the kingdom.

Pretty much made up my mind, I am going to keep the roof I have apply lathes and insulation on top and

then new tin over it all..

 

[artie]

I am making a start on the roof next Tue.

I am removing the old corrugated tin and replacing it with box profile cladding with the non drip coating on the inside.

We will see if that is sufficient.

Does anyone know what kind of fitting is available to take a 6' oil burner flue out through this and seal out the rain.?