Spray on protection for rust prone tools?

I seem to remember the bikers' group recommends ACF50, and gun communities seems to use Balistol

I have the same problem. There have been many times when I've been into my garage and found the metal parts of tools literally drenched in condensation.

It is particularly bad when the temperature has been very cold and then due to a warm weather front, the air temperature rises and the humid air condenses on the cold metal.

There are commercial products such as WD40 and Duck Oil which will work but these will leave sticky/waxy films.

I have a lathe and mill and what I have now used for a couple of years are large polythene bags, actually mattress bags, to cover the machines when not in use. I also cover the lathe with some old blankets.

I also place a small mains powered heater of approx 15 watts to keep the air in the bag slightly above ambient. So far seems to be working fine.

Ive not done the calculations, but a de humidifier and a humidity sensor might use less electricity

I find WD40 adequate. Cheap, easy to use and readily available. Sometimes preceded by a powered wire brushing for big castings. The lathe lives under a plastic table cloth (nobody asked where it went).

A timely reminder with the current atmospheric conditions!

Remember there are two types of dehumidifier. There is the one with a compressor in a refrigeration configuration and the other which uses silica gel which requires periodic regeneration, usually in a domestic oven.

However both really need a well sealed environment, gaps in outside doors admitting air will really hinder their effectiveness.

I use Cosmoloid H 80.

"Acid-free wax for metal preservation. It is colorless and does not react with copper, which makes it ideal as a corrosion protector, even for iron. To form a protective layer, 20 g of wax can be dissolved in 1 liter of solvent (white spirit or Shellsol® T) and applied with a brush or spray gun. Alternatively, the metal part, previously heated, can be immersed in the liquefied wax (melting point around 100 ºC)."

I spray or brush on the white spirit solution, and sometimes go over the metal with a hot air gun or propane torch to melt the stuff onto the metal. This keeps iron, stored outside but not in direct rain, rust-free for a year to years. It does not leave a palpable film, and is neither greasy nor oily. A liter of solution goes a long way, even it dipped, or generously slobbered.

It may be overkill for you -- I can walk to a store that sell the Cosmoloid over the counter...

You might try candle wax dissolved in warm white spirit (careful!) as a substitute.

Thomas Prufer

I would say that gaps in outside doors will render their effectiveness basically null and void.

Same goes for heating then

Third type is the desiccant disk type. Having seen many of those at Repair Cafes, I would never buy one and would warn never to use one unsupervised. If the disk stops rotating, the heater will set light to it.

It's difficult to dehumidify at low temperatures. Even though you may be at the dew point (100% relative humidity), the amount of moisture the air holds at low temperatures is low anyway. A refrigerant dehumidifier will work, but will have to cope will with the evaporator freezing and running defrost cycles. Even the small domestic dehumidifiers which claim to have defrost cycles - they rarely seem to work, and finding the thing is still running flat out when completely blocked with solid ice and has never attempted to defrost is not uncommon.

What actually works very effectively when dehumidifying at low temperature is to just heat the air a little. Because warmer air holds more moisture, you only need a very tiny amount of warming to take the relative humidity from 100% down to 80% (at the same absolute humidity or dew point) which will prevent condensation.

The shed contains soft furnishings, timber, and metalwork, and none has gone rusty or damp in the 10 years. The stuff was originally in storage at £200/month, and I worked out the shed's electricity cost was around £50/year (that was before the celotex was put up). The Pi controller also incorporates frost protection to prevent the shed dropping below

One interesting thing... The controller also monitors the outdoor temperature and humidity. I monitor it remotely, and I noticed a sudden increase in the amount of dehumidifying required for the same outdoor temperature and humidity. I wondered if the door or window might have been left open (not that we'd done any draftproofing). On investigating, the roof had started leaking water inside, which was an additional source of moisture which had to be coped with. On fixing that, usage went back to normal.

Many, many years ago I read an article in a science magazine about why buildings left empty and untended for years, such as abandoned stately homes, tend to deteriorate. Apparently, the destructive action was that of humidity cycling. The article recommended keeping buildings about 5degC above the outside temperature. Clearly this was written well before software-driven controllers such as you describe were available.

In Arizona there is(are) aircraft storage lot(s) where airlines send aircraft which they have temporarily taken out of service. The climate helps to prevent deterioration due to humidity.

Thanks for all the detailed advice on this. I don't think my situation is suitable for economical heating or dehumidifying.

I'm going to go for the belt and braces effect of ACF50, Cosmoloid H 80 and plastic bags and containers where possible.