My workshop is in a detached brick built double garage 20' square with
a pitched roof. The two up & over doors are blocked off (one is
sealed with foam sealer and the other has a polystyrene lined
hardboard skinned pannel in front of it). Most of the walls are
polystyrene/chipboard lined. At the moment the temperature is about 5
degrees (just to cold for comfortable working). When I want to work
in there I use a small fan heater to lift the temperature a few
degrees -8 degrees seems OK to work in. I run a dehumidyfer, but at
these low temperatures it is obviously of little use.
Given the size of the workshop, would one of the small "greenhouse"
type of electric heater have any impact. It would be nice to keep it
a couple of degrees warmer -so it takes less time to get to a working
temperature, and to minimise condensation risks (not that I have a
problem at the moment, but I do have nightmares about damp!). If I
were to use one of these what size would it need to be to have an
impact. I'm looking at leavign this on all the time, so if it needs
to be too large a wattage it will obviously not be practical (I need
to be able to pay the electric bill!).
I use a paraffin space heater in mine (jet engine type) 130,000
btu........the secret is to heat it 24/7.
I have the space heater on a thermostat.....this I wired into its mains
I have it set at about 17 degrees.
I have no problem with condensation at all ...a little bit on the
windows... not much.......as all the machines ,walls and air after a
few days running equalise in temp.
I have a small vent at each apex to bleed off a tiny proportion of the
hottest air which contains nearly all the moisture.
running this way over the last two weeks (cold spell) it has used an
average of 1 gallon a day.............paraffin in bulk costs about
=A31.40 a gallon.
My workshop is about 25 by 25 with an insulated roof but solid concrete
walls and single glazing .
During the coldest days a few days ago it was on for eight Min's every
when you first turn it on for the first time,for three days you will
have bad condensation problems .but after that ...when every thing
begins to heat up ..........it's great .....no trouble.
Think doing the same with any other bought fuel would be mega
It may put a gallon of moisture into the air with every gallon
burned....but all I can say is I've not noticed it ........I have a
humidity gauge on the wall that reads a constant 55 % moisture level .
the up and downs in temp with this set up are 15-25 degrees when run.
(thermometer is on a wall that is away from the blast)........the 25
degees quickly disperses and gets the workshop to a Nice 17 degrees
when the heater switches off.
all the best....mark
I have a workshop / garage 20' x 40', I have a fan heater on a thermostat
set to cut in at about 0 C, this stops the pipes freezing.
I have a vent 250 x 150 mm at each end, and I have not sealed the garage
doors though I have fitted a 'skirt' to stop rain splashing in under the
I put the thermostat up to 10 C when I'm working.
I have had no damp problems.
The way to keep damp at bay is to keep water out, this includes not running
fuel burning heaters that do not exhaust out side, and letting hot ( and
thus moisture bearing ) air out...
I have a de humidifier, but it's useless below about 5C.
Any kind of background heating is going to be lost if the insulation and heat
retention of the place are not up to scratch.
If you can reduce heat loss then almost any small electric radiator would keep
it at a low level at a small cost.
When we moved into our new factory back in 1982/3 winter, we had to have a big
gas power blower heater to keep it at all comfortable, and we used a couple of
56kg cylinders a week.
We then spent £2k on a suspended ceiling and partitioned off the stores area
from the offices, and now we have a couple of 6kW GEC wall-mounted fan heaters
that we run in the winter, probably one continuously and the other
internittently, and that keep nearly all of the 900sq ft at a nice temperature.
They are both on timers and come on at 6am so the factory is warmed up before
staff arrive. One goes off at 10am and the other stays running on cold days.
The key was the ceiling, it kept any heat down where it could be felt. We didn't
insulate the ceiling, it's just a standard micafil type ceiling board, about
1/2" thick. If we added insulation it would probably improve things even more.
I'd be inclined to get your pitched roof sealed off so you can retain heat at
your level first, that will help a lot.
Peter & Rita Forbes
My workshop is a similar area to yours, well insulated apart from the
draughty double doors and the concrete floor. I run a dehumidifier
most of the time, it does contribute a small amount of warmth even
when things are too cold for it to do its main job.
I have two old 1kW industrial 'space heaters' bolted to the walls,
just a simple convector heater probably similar to a greenhouse
heater, one of these is often enough to take the chill off, the
second gets used when things get a bit colder, and for seriously cold
weather I have a portable ceramic element infra-red radiant heater
which is very good for local heating. That one didn't come out at all
last winter, I have a feeling it might do this time, though!
One of my 'space heaters' was in my un-insulated attic bedroom over 40
years ago, if I forgot to turn it off I was likely to get my pocket
money docked :-( I have to confess that these days I sometimes leave
it on all day or night if the weather is very cold, I only have myself
to answer to over the electricity bill
Traditional & Modern canal craft repairs
Vintage diesel engine service
As I understand it, you need to keep the temperature in the worksho
fairly constant. It's no good if during the day you keep it warm an
let it go too cold overnight because the moisture in the warm air fro
the day just condenses out on the cold metal overnight. Again I'm no
sure but I think greenhouse parafin heaters also promote moisture i
the air but I can't remember why (byproduct of what they'r
combusting?). A dry heat like that coming from an electric fire or
central heating radiator are the ideal solution. If there i
condensation on your machines in the morning, wipe it off with pape
towel before putting the heater on. Either that or cover the machine
in some old cloth or paper towels to absorb any condensation when yo
go in at night (and of course, keep the machine surfaces oiled)
Good points here. Combustion leads to water and carbon dioxide when
burning most things - gas, oil, paraffin etc. Warm air can take up a
lot more moisture than cold. And big lumps of metal take a lot more
time to warm up and cool down than air. You need to avoid warm moist
air and a cold lump of metal, cold air and warm metal is fine.
So a constant temperature sounds good, that keeps metal and air both
warm - so you might not get condensation on the tools even using a
combustion heater. But if you let everything go cold overnight, then
warm up the air with a combustion source, then the cold metal on your
tools can condense water out - just the same way your glasses mist up
when you walk into a warm pub on a cold night. So if you are going to
let things go cold overnight, then use a dry heat to warm the air when
you are in there - e.g. from a radiator or electrical. If its a very
small shed your own breath may still make the humidity go up enough to
cause some condensation - as will your kettle.
24 hour heat also means unattended heating - so it had better be super
On the other hand using cold tools make you feel chilly too, and 24
hour heating does at least keep them warm-ish.
I think dry background heat 24hrs to keep the chill off, and electrical
warm air or radiant heater if you feel its still too nippy when you are
in there. I don't like the idea of an unattended combustion heater in
Exactly. I believe most of the oxidation (rust) happens as the wate
evaporates off which is why drying the machine with a paper towel i
preferable to letting the hot air do it when you first put the heate
on. It's also why you shouldn't put away a wet car in a warm garage
Keeping the lathe's temperature above the dew point of the atmospher
at all times is the ideal scenario
Your going to need ten 180 watt ones in a 20 by 20 BUILDING to keep it
at a nice temperature .that equals 1800 watts
that's 43 units every 24 hours in cold spells, if it was ten pence a
unit that would be =A34.30 a day !!! =A330 a week !! and thats a low
guesstimate you may need more.
if your afraid of naked flames and combustion .why not just install an
oil fired central heating boiler outside in an outhouse ........and
have heaters running off it .........this would probably workout
nice...about the same as what I'm paying.
or pipe the Central heating over to the workshop
before i insulated the roof of my place i worked out that it needed a
constant 4000 watts of electricity to keep the place at 17 degrees by
running a few fan heaters in there with outside temps of below 5
I've done a bit of research into this ..my answers are based on that
.=2E.im not making anything up.
waste oil heating is the cheapest solution.........I'm working on this
.=2E........well I would be if i didn't keep getting diverted onto other
projects.............sort of .miniature version of the thermobile
because their smallest one is to big.
all the best........mark
.=2E. Because paraffin produces copious amounts of water vapour as a
byproduct of combustion... far more than other fuels. Paraffin is the
'last' thing you want to use to heat a workshop.
But all of this is like dejavue to me.... I have been 'off-line' from
the model engineering groups for some time (about 2-3 years) until
fairly recently ... and one of the last threads I recall (from the then
group I subscribed to) was exactly on this perennial subject.
There is another thing you can do to help with keeping rust off the
Make them some 'cosies' ...
.=2E.(as in the old tea-cosy ... seriously).
We had a small division of the company I used to own which made
industrial covers for machinery. We supplied them with moisture trap
pockets inside (basically a number of small bags sewn on the inside
which contained a kilo or three of Silica Gel). Originally these were
developed for temporary external storage covers for sensitive or
delicate items (where for whatever reason the item couldn't be got
under cover for a week or two). I had some of our covers made for my
own workshop equipment and they performed brilliantly. We used to
bespoke make them for folks, but haven't done for some time. We also
made large versions for Caravan storage.
If you want to make them up yourself all you need is a nice new (cheap)
tarpaulin large enough to completely cover your lathe/miller etc (with
spare space), a set of measurements for your machine, a
wife/friend/colleague/Mum with a robust sewing machine (the old Singer
Treadles are perfect as they will stitch just about anything ), 2 or 3
kilos of Silica Gel (probably the hardest thing to get in this quantity
as it tends to come in industrial quantitites of at least 50kgs), some
of the ripstop nylon netting they make Koi/Tropical fish nets from, and
a bit of nylon rope to use as a 'drawstring'.
Make the pattern ... cut out your tarpaulin fabric ... 'double' stitch
it together ... have the bottom hemmed to incorporate the 'drawstring'
.=2E. stitch the net bags inside regularly spaced (best if they don't
actually touch the 'sensitive' bedways but are held just above)... then
cover the machine immediately you have finished using it and whilst it
is still warm, tuck it all in nicely to keep it 'cosy' and drawup your
drawstring. Make sure the Cosy reaches to the floor or within an inch
or so of it.
It won't completely kill the need for trace heating in all
circumstances, but my old Harrison has been wearing it's cosy for 6
years now in an unheated workshop and the beds are exactly as they were
when I started. Not a sign of rust and that included an 18 month period
of zero use whilst I concentrated on the fine work with the watchmakers
By comparison I bought a Bridgeport 2 years ago and put it in the same
workshop and (for lack of time in having a proper cosy made) simply
covered it with an old bit of carpet and a sheet ... BIG mistake...
within weeks I had severe rust on the table. Should have taken my own
advice ... but got lazy.
You need to take the Silica and dry it out every now and again... But
if the machine isn't being used (as in my case for 18 months) the
Silica will continue to work for months/years(?) Whenever you start to
see pink or blue spots appearing (depending upon which type of Silica
you get ... look in Yellow Pages for Chemical Supplies ... if anyone
gets stuck I might be able to help with supplying some).
By covering up the machine whilst warm with a non-porous material you
are effectively creating it's own little micro-climate... reducing the
temperature gradient, as the ret of the workshop cools, and the Silica
draws moisture from the atmoshere reducing the humidity inside the
cover. Both elements reduce the likelihood of condensate forming on the
machine itself. Someone will say that it isn't foolproof... (which I
don't claim it to be) ... but it does help greatly. Cost ? ... about
=A340 all in for something the size to cover a lathe the size of the
Harrison, or about =A350 for a Bridgeport, or if you have to pay soeone
to make it for you about double that price would be fair (there's some
heavy sewing involved... be prepared to bribe 'SWMBO').
Hope this gives some 'food for thought'
In message , Adrian Godwin
If, for one reason or other, it is impractical to keep the whole space
at the desired level of temperature and humidity, then why not?
For a few years my lathe survived very well in a damp and unheated shed
while covered with an old army blanket plus a large old candlewick
bedspread that draped down to the floor. Under the lathe, on the floor
and permanently lit, was 25watt bulb protected by an inspection lamp
Meanwhile a couple of large unprotected pieces of ferrous metal suffered
the ravages of the slow red plague.
I read somewhere (on this forum?) that leaving a low wattage lamp o
in the bottom of the lathe/mill stand was a way to keep the too
moisture free. I've not tried it myself, though.
Even putting a simple plastic cover over your lathe makes a bi
difference. It acts as an insulating layer against temperatur
extremes. Coldness won't hurt machinery per se. The damage is done b
moisture condensing out of warm wet (or cold wet) air onto col
machinery. You either have to stop the moisture condensing out throug
temperature, in which case you need to see that the machinery is kep
relatively warm, or use a dehumidifier. If you want to use you
machinery over the winter comfortably, the only completely safe an
ideal solution is to constantly heat the room that they're in
Keeping a thin layer of oil or grease on all exposed surfaces would work as
well if not better than managing and monitoring the heating and humidity
And no, heating by the ways you note would not be the best answer for you
would be left with the problem of damp in the air all the same, and the
extra heat would increase the reactivity of the steels.
I run a large, 2 foot square by 4 foot high sawdust burning stove
although for the last two years it's been on scrap wood.
I'm fortunate around here as there are literally dozens of small
furniture manufacturers and scrap beech wood is free for the
Anyone who has been in my shop in winter will tell you you can't stand
near my stove.
It only runs during the day and it does get cold at night as I have no
roof insulation as yet.
Since fitting this I have no problems with rust and I don't oil up
only for lubrication.
My biggest problem is the roof and draughts plus having to get about
17 tons of material and machinery up from cold in a morning every day.
Before this I had a space heater and it was useless, fumed, caused
condensation and as soon as it switched of you were freezing again.
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