Desiccants for rust prevention

[Sonic EscapeParticipant @sonicescape38234]

I noticed that my precision vise has a few rust spots. It is only one year old and it was nice and shiny. I have also a lot of of greasy milling cutters that I want to clean and I’m afraid they will start to rust after. I’m thinking on a simple way to prevent rusting for the tools that I’m not using very often. And I don’t like to cover them with oil.

To make a test I put a 500g calcium chloride bag in a box. After 5h the humidity dropped from 49% to 19%. Is this dry enough to prevent rusting? Calcium chloride is relatively cheap since it is sold as replacement for room dehumidifiers. But it is bad for lungs. And I think it creates some hydrochloric acid when absorbs water.

I’m thinking also on silica gel. It is suppose to be less effective but is chemically inert. You can buy it in large bags for cat litter.

I can store the tools in large zip bags with some desiccant. Or maybe custom build a tool cabinet and put a few kg of calcium chloride on the bottom? The cabinet will be hermetically sealed of course, to don’t slowly dry the planet.

 

[JAParticipant @ja]

At one time a little ceramic dish of concentrated sulphuric acid place with a model in a cabinet was popular.

However I don’t think you have quite asked the right question.

JA

[peak4Participant @peak4]

I’ve lined drawers with VPI/VCI paper; the stuff that tools are sometimes wrapped in from new.
It depends on the size of your tool collection, but a reasonably airtight cupboard and some VCI/VPI pods might do the job.
Many years ago I rescued some from a router delivery at work and used them in my micrometer cupboard to reasonable effect.
In my camera cupboard I keep a large bag of silica gel, and refresh it every now and again in a cool oven.
It does need to be a decent sized bag though; mine’s at least 500g
This is one example of a VCI pot, I’m sure they will be available closer to home for you
https://workshopheaven.com/shield-technology-toolguard-vci/

Bill

[Sonic EscapeParticipant @sonicescape38234]

I didn’t knew about VCI. Looks like a good option. Those VCI pots are empty after that substance evaporates? Or is there other clue that you have to replace them?

[duncan webster 1Participant @duncanwebster1]

Low wattage heater in the cupboard would work well. SOD did an article in ME some time ago about measuring relative humidity with Arduino and switching heater on/off as needed.

Many electrical switchgear cabinets have a heater in the bottom for just this reason.

[Sonic EscapeParticipant @sonicescape38234]

But how does this work? Warm air can store more humidity.

[duncan webster 1Participant @duncanwebster1]

If the tools are at a higher temperature than the dew point of the general workshop air you won’t get condensation. You need liquid water for rust.

[Bill PhinnParticipant @billphinn90025]

And I don’t like to cover them with oil.

 

 

Regardless of the supplier, whenever I buy a new end mill or slot drill it comes in a telescoping plastic tube. The cutter inside is always oiled or waxed in some way by the manufacturer.

Every time I put new cutter away after use with no intention of using it again for a while, I blow off the swarf and put a drop or two of oil on it before putting it back in the tube. It takes about 10 seconds.

Secondhand and seldom used cutters of any value that came without a box are stored in gripseal bags.

Smear some Waxoyl on your precision vice. As the name suggests, once dry it leaves a waxy rather than oily finish.

Supplying a smear of Waxoyl, a drop of oil and plastic containers of some kind is a whole lot easier and cheaper than controlling the humidity of my workshop.

If you really don’t want to use oil, can you store your infrequently used tools in your living areas?

[BazyleParticipant @bazyle]

I seem to have to keep repeating this every few months. Get clear Waxoyl and dilute with white spirit about 50%. Paint it on everything metal that doesn’t actually need lubrication oil to work.
It dries to a wax that feels like the glue on a post-it. Much nicer to handle than oil and very effective for years. For machine handles and things you touch use beeswax furniture polish but NOT silicone polish.
If your church has 7 day St Patrick candles see if you can get the used ones as they have a little soft wax at the bottom – the blue capped ones are beeswax. This can be smeared over sheet metal stock if slightly warmed.

[Chris MateParticipant @chrismate31303]

I have tried a few things, I have wooden segments(easy to make) in tool cabinets have painted them, put MT4’s in compartments, only to find one resting on leather with a bit of surface rust. Since then everything is in a plastic bags(Oily 68), bigger stuff in a plastic container with oil 68 sprayed over it with lid(Keep dust out), liike .

So far this method works for me, drawback   I must wipe off oil before use, but thats better than facing rust/dirt. It would be impractical for a busy shop, but could still work for stuff rarely used.

I use spray cutting oil, that helps for mill bed and lathe, so far no problems there.
So far motorcycle covers works well keeping dirt out.

[Robert Atkinson 2Participant @robertatkinson2]

1/ The “Silica Gell” sold as cat litter, flower arranging and the like is not the same as the dessicant type. It absorbs liquid water and turns to a gel. The dessicant type absorbs water vapour and does not turn into a gel, even if you put in liquid water.

2/ For protecting delicate tools Renaissance Micro-Crystalline Wax is a good choice. Designed for the purpose. https://priorypolishes.co.uk/product/renaissance-wax-polish/ Available from many other suppliers.

[Robert Atkinson 2]

On Robert Atkinson 2 Said:

1/ The “Silica Gell” sold as cat litter, flower arranging and the like is not the same as the dessicant type. It absorbs liquid water and turns to a gel. […]

I wish I had known that before I bought the bag of cat litter

🙁

MichaelG.

[Norman BillinghamParticipant @normanbillingham91454]

I would be careful using calcium chloride as a desiccant long-term.  It’s deliquescent – absorbs so much water that it turns into a liquid aqueous solution.  OK for short-term use in closed spaces, and with regular replacement but if left for too long with any access to water vapour, you can get corrosive liquid forming.

[Howard LewisParticipant @howardlewis46836]

It used to be possible to buy tubes of Lanolin to smear bover items to be kept rust free.

Very long lasting, so used for things like old fashioned verniers that are unlikely to see frequent use)

It is VERY glutinous, so it spreads more easily if the tube is heated in hot water before squeezing it out onto the item, to spread. The heat takes from nearly solid to oily, so easier to spread and a thinner coating.

Low wattage heater hopefully keep the temperature above the dew p[oint, so that condensation does not take place.

Ventilation helps. Have a small fixed vent at floor level, so that the moist air can escape.

Doesn’t always help. Adter the local “monsoon” season, was horrified to find the lathe chuck with a thin film of condensation! 60 watt heater ON, and lots of wiping!

[Howard Lewis]

On Howard Lewis Said:

It used to be possible to buy tubes of Lanolin to smear bover items to be kept rust free.

Very long lasting, so used for things like old fashioned verniers that are unlikely to see frequent use)

………………..

Lanoguard might be a modern easy to obtain equivalent; I believe regularly used in Australasia for automotive rust protection, it’s now becoming popular here; just the plain spray stuff, not the fancy versions.
https://www.lanoguard.co.uk/collections

[duncan webster 1Participant @duncanwebster1]

Lanolin was widely used in cosmetics. The main source was Esholt sewage works, recovered from washing sheep fleeces when Bradford had a big textile industry.

[ChrisLHParticipant @chrislh]

In my early days I worked in Bradford next door to a wool processing factory. They washed fleeces every last Friday of the month and the stink was awful even at that stage. Somebody must have worked hard to find a way to get rid of the smell. All gone now with the whole site occupied by retail outlets where money is being spent instead of being made.

[larry phelan 1Participant @larryphelan1]

Michael, buy a cat, problem solved !!!

[larry phelan 1]

On larry phelan 1 Said:

Michael, buy a cat, problem solved !!!

Good try Larry … but it “does not compute”

I have more than enough problems already.

It did, however, lead me to the more appropriate solution:

As we have a couple of local charities … I can donate the Kitty Litter to a Litter of Kitties.

MichaelG.

[Kiwi BlokeParticipant @kiwibloke62605]

The only time I’ve used lanolin for rust prevention, it dried (and oxidised?) to a sticky mess and stank!

+1 for Waxoyl. Not available in NZ AFAIK, but Morris’ Ankor Wax seems much the same.

However, the OP asked about dessicants. Silica gel and airtight bags work well for me (in this low rust-risk environment).

[Author]

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