How should one protect ferrous tools?

WD40 works for me. We get about 8 feet of rain a year here and it's always humid.

Shooting enthusiasts used to swear by Rangoon Oil as an anti-rust agent, and I believe it was used by the British Army in tropical climes around 150 years ago. I see it is still available, but some examples are labelled "improved formula". Problem is, I dont know what the original formula was. Does anybody? All I can find out is that it was a "clingy" sort of oil with an extremely low evaporation rate. If it was effective on steel in tropical jungles in the sweaty hands of soldiers, it must have been good stuff!

This was 'done to death' years ago in ME with trials of every different product.

The winner by 'miles' was Three-in One oil.

"If you come into a damp cold workshop and put a heater on, water will be forced out of the air and condense on the nearest cold surface"

. . . . . .really !!

What really happens is that the warming air is able to take up more moisture so no condensation takes place on the heating part of the cycle. Condensation takes place when the temperature falls and the air is less able to hold all the moisture you just breathed into it. In the winter it's good to vent the warm moist air out of the workshop when you have finished. The replacing cold air from outside will contain less water and you get less condensation when the tools cool down. Essentially you have to stay the right side of the dew point.

regards Martin

I guess you're both sort of right really because as the air temperature in workshop increases with the heating on the dew point also increases.

So even if you didn't breath and increase the humidity that big lump of cast iron will lag the air temperature and eventually fall below the dew point even while the heating is on and as the workshop cools more and more moisture will form until the dew point is below the temp of the cast iron lump.

Jon

Edited By Jon Gibbs on 14/09/2016 08:51:45

Edited By Jon Gibbs on 14/09/2016 08:54:18

Another big plus for ACF-50.

It works very well also against salty conditions.

Proven by many on their bikes thru' the winters salted roads on both ferrous and non-ferrous surfaces.

Just try missing a bit of the surface like i did and you will realise just how good it is.

Edited By MalcB on 14/09/2016 09:07:32

So say you start at 10 degrees and 70% humidity and heat the workshop to 20 degrees without adding any extra water you end up at around 38 RH. Better. If the air at the surface of your iron lump is still at 10 degrees it will still be non condensing as nothing has changed. Start to pump water into the atmosphere by breathing and the humidity will go up including at the iron lump. This as Jon says could lead to condensation in a tiny workshop with bad ventilation.

The essential thing is to understand where the water is coming from and mostly it will be you.

Ventilation is everything. Install a fan if you are going to heat your workshop. Don't waterproof the walls unless you are trying to stop damp coming through from outside. Plenty of absorbent materials like wood around. Buy a cheap humidity meter and do a test. Resist the temptation to seal all the draughts and paint all the walls. Avoid large temperature swings.

regards Martin

ACF-50 is indeed excellent. Even better, I think, is the imaginatively-named Corrosion Block, from the same manufacturer. It's more viscous than ACF-50, and hangs around much longer. I believe that ACF-50 slowly evaporates. Just a wipe with a rag impregnated with the stuff is all that's needed - a smear goes a long way. It's also an impressive penetrating oil.

...oh, and another thing. 'Hydraulic oils' typically contain anti-foaming additives (not relevant here, of course) and corrosion inhibitors. Esso Nuto H32, or equivalent, as advised for Myford lubrication (but not slideways), is a nice oil to have around the 'shop - light, and suitable for general purposes. Automotive engine oils typically contain detergents, which messes up their water-displacement properties. They are not good for corrosion protection, although no doubt there are exceptions. I believe that automatic transmission fluid is OK - perhaps it's similar to an hydraulic oil.

I also used to have "rusty" hands and can remember in my 30's anything steel based at both work and home that I used regularly were discoloured and dull. One of my colleagues, in his late 40's/early 50's never had a problem with his work tools: they were always bright and shiny. Didn't seem to affect the work though.

I'm now in my early 70's and everything is now clean & bright. So I appear to have outgrown my "rusty" hands. I suspect the answer is sweat!

As far as the engineering equipment is concerned, I used to use WD40 to protect the lathe. Bit smelly, and I often had to clean it before I could use it. Then, following correspondence in either ME or MEW, I bought some electric self-regulating heaters from RS. There are various wattages - mine are 10W. I fitted two to the lathe bed and stopped using WD40. No more rust or corrosion, and the lathe never has that bone-chilling numb inducing cold feel about it, even in the depths of winter. Fairly obviously they work by maintaining the lathe temperature high enough to prevent condensation. In addition, I also use a woven fabric cover - not sure what it is made from - and a sheet of plastic. the idea being to try and keep the heat local to the lathe. The plastic serves another function as well in that it protects against any water ingress - my garage roof is hardly the best despite now being in its 2nd replacement in 20 years.

The downside is that these heaters actually run at about 19W each, which is actually as per the specification, hence I have a constant electric drain of 38W from the lathe along with a further 19W from the milling machine which has one fitted. Ok, it costs money, but as far as I am concerned, it is worthwhile because it prevents rust and corrosion on expensive machinery.

Other people have used other means of heating their equipment - incandescent lamps under the bed, self-regulating heater tape etc.

Regards,

Peter G. Shaw

Edited to correct spelling mistake.

Edited By Peter G. Shaw on 14/09/2016 13:03:22

Good point Martin - I worded that badly! What I was trying to say that turning on a heater first thing in a cold damp workshop will warm the air before it heats the tools. Condensation can then take place on the tools whilst they are colder than the air.

The mechanism you describe also makes a lot of sense. Breathing or - even worse - using a blowlamp or paraffin heater will put a lot of moisture into the air. When you stop work that water has to go somewhere.

Thanks,

Dave

I would say that its the floor is trying to keep the garage at a low temperature. As said, wooden sheds if insulated or vented do not suffer too badly from rusty tools, at least mine has not with over 30 years use. One very easy experiment is to put down a sheet of plastic on the floor (foot square?) with a brick on it. After a week lift the plastic and see if its wet. My present Celcon built garage that has some kit in it seems to be 100% dry but it has an up and over tin door. So a balance of thermal loss and ventilation? I suppose the water table/ wet winds will affect it. Unless you can actually see wet on the inside of the walls, I would not bother with damp proofing. Air is very slippery and will just leak through bricks and paint is only about 60% air tight.

Had a thought:- how about roof insulation, so during the day solar energy is trapped within the building and leaks out so slowly, at night the building does not cool down to dew point? That has been one common factor with my outhouses.

Frank

Thanks all for yet more useful input.

That's particularly helpful Frank. I'll be provide further details of the workshop as is so hopefully specific advise may come about:

A double external garage with gabled roof of trussed rafters support. Floor is one giant concrete pouring. Not sure if membrane below - will do the plastic sheet test! Two up and over tin doors.

Workshop is one quarter of floorspace partitioned by insulated wall, and the roof joists have insulation between them and are boarded below for the workshop ceiling. Hence the worksop has: two insulated plywood lined wall, one concrete/brick single skin wall, and the tin door.

Yes roof insulation would be ideal BUT sadly I cannot insulate the roof below the felt because of another hobby of mine - an observatory in the roof space above workshop. Poking telescopes and cameras through insulated roofs, that as you say slowly re radiate, are a big no no RE optical quality. Thus why I'm careful to provide a good thermal barrier at the joist level, not at the rafter level.

I ordered a basic hygrometer as advised. I plan to record % relative humidity values over a few days to see what I'm dealing with. Does anyone know what appoximate values are desirable in a workshop?

Lower the better is the simple answer. If there was no moisture in the air your tools wouldn't rust!

Zero humidity is expensive to achieve and the problem of condensation is also strongly related to temperature changes. Aiming for a particular target feels like overkill in a home workshop.

I would use the hygrometer to try and isolate if the garage has an intrinsic damp problem or not, This can be done by comparing readings taken in the garage with readings taken at about the same time outside. Depending on the weather, you may need to take several sets of measurements because humidity naturally varies considerably. Local weather forecasts on the web will often tell you what the humidity is expected to be - the BBC tells me that Bristol is 51% today.

If the garage is consistently more humid than outside, then there's an intrinsic damp problem to be solved by the measures described earlier in the thread. You can buy a moisture meter for about £20 that will show if a particular spot on a wall or floor is damp. These are useful for pinning down where the water is coming from. (Blocked gutters, drains, rising damp, or porous walls etc.)

By the way new builds are notoriously damp until they've had time to dry out naturally.

Once any intrinsic damp problems have been controlled and you still have rust, use the hygrometer to see if the humidity increases whilst you are using the workshop. If it does then you need better ventilation or a dehumidifier. (Mine was on offer from Screwfix for £80.)

Another old trick that seems to work is to keep your tools in a wooden box rather than a metal container. Likewise, storing tools inside bags and providing covers for larger machines will help too.

Cheers,

Dave

Edited By SillyOldDuffer on 17/09/2016 10:51:22

Here is an interesting take on why things get rusty. **LINK**

Given all that I find that covering all my machinery with plastic drop covers and then old cotton sheets seems to work quite well.

On a wet and humid day, the cotton sheets can be quite damp but the lathe and mill beds are unaffected. Maybe the cotton sheets absorb the moisture and the plastic keeps the damp isolated from the hardware.

Whatever, it works.

Also, I use lanolin based products such as this:**LINK** as apart from being a decent aluminium cutting fluid it works well to protect the machinery.

Have you ever seen a rusty sheep?

* Danny M *

Insulating the shop is one way to avoid rust. My rather small wooden clad, framed and panelled shop has 50mm of glassfibre in walls and roof. The floor is 18mm ply on 8 x 2 inch bearers, which are/is closely surrounded on three sides.

Damp air is heavier than dry, so position a small vent as low down as possible, so that the moist air can escape.

Also, try to avoid sudden changes of temperature. If frost is forecast, I turn on a 60 W tubular heater, sited under the bench. After a couple of days, the shop does not feel cold, nor does metal feel cold to the touch. If I am working in there in low ambients, there is a 2Kw fan heater, fed through a thermostat.

Uninsulated Concrete walls seem to be especially prone to condensation. A friends workshop, with concrete walls and roof has glassfibre insulation, with a vapour barrier behind the internal cladding. He no longer has problems with rusting.

Howard

Just as a crude piece of advice for some but i found it definitely works. Just leave the window open ajar if you heat the building.

Some guy told me once that these special superduper I.R heaters don't generate heat in the same way, could be whack but who knows, i do it the cheap way.

Oh and for a ye olde title "Howe doth aye protect ferrouf toolf ?" 

Michael W

Edited By Michael Walters on 19/09/2016 19:00:51