Chalk as a desiccant?

[Irving]

I was looking up ways to reuse old chalk, like melting down old candles to make new ones. I didn't find what I was looking for, but I ran into a lot of stuff saying to store old chalk with your silver, or other metals to absorb moisture and keep metals from rusting or tarnishing.

I have pounds of old chalk stumps hanging around my house. Is there any way to test the effectiveness of chalk vs consumer desiccants? Someone on here has a moisture meter in a safe somewhere don't they? Let me know and I can donate the chalk. It'd be worth the experiment just to find out I think.

[SA Friday]

Chalk, calcium carbonate, CaCO3, Not that I've ever seen in the Chemistry texts.

The easiest household materials that are desiccants are epsom salt (MgSO4 - 5 H2O) and Gypsum (dry wall) (CaSO4 - 2 H2O). Others are silica materials like silica oxide and activated charcoal. Desiccants capture and retain water molecules in a gas state. The amount a chemical can retain is shown by the second portion of the chemical formula. So, epsom salt can retain 5 water molecules and gypsum can retain 2 water molecules. To determine the efficiency of a desiccant, one would heat up the material over 212 degrees F for a couple hours and dry out the material attempting to achieve no water retained within it. Weigh the desiccant on an extremely accurate scale. Then expose the desiccant to the system (your safe in your basement) for a specified amount of time. Reweigh the material and determine how much heavier the material is.

Depending on just how deep you want to go into this or just how fucked up you want me to mess your head up, you can do the math (things like Avogadro's number, 6.0221409 x 10^23, start coming into play in the formulas just for a taste of fucking your head up part) and determine how many molecules of water you retained and compare that to the about of molecules you started out with to determine what percentage of water retention the material achieved during it's exposure to the system in question. Or... you can just do it with different materials and determine which one retained the most water for equal amounts of desiccant. Either way mid-to-high-level math skill must be employed to achieve any results. Oh, and about a $1600 scale... and a couple years of chemistry lab training so your methodology and physical manipulations don't skew the results.

Then again you can just fill a decent sized container full of epsom salt and put it in your gun safe. Once every month or two, put the container in the oven and heat it up to about 250 degrees F for about an hour or two and then let it cool. Then just put it back in your safe.

[Irving]

What is the math skill involved if you're just weighing before and after?
Is a Prometheus powder measure accurate enough? What kind of time span would be appropriate for a test? I imagine that the moisture absorption would run on a diminishing returns kind of scale and say 85% of the maximum absorption would be achieved within a specific time span.

[KS63]

^^^You got a Prometheus? Lucky guy.

[Irving]

No, I just have chalk. Someone on here does, I thought.

[Monky]

Tl;dr


Sent by a free-range electronic weasel, with no sense of personal space.

[SSChameleon]

Ten best use for the chalk is to grind it up real fine. Two/three days a week, wipe a little at the base of your nostrles and be sure to talk a little faster and open your eyes real wide. Then, when the SHTF, no one will suspect you as a prepped and they will leave you alone rather than try to raid your house.

[fitz19d]

So with this idea, what about a larger foot print shallow tray full of rice or even just a ton of the little packing dessicant packs? This isnt for a safe, but instead just a room with higher humidity from a fish tank. Removing and heating/leaving in sun seems better than powering a fan and having an opening to the outside, especially during high summer/winter.

[Irving]

I don't think any reasonable amount of desiccant can match the humidity of a 300 gallon fish tank.

[fitz19d]

Actually for basement where the smalller sump is. I've got other stuff in works for the 300 including just the fact the room has essentially 3 walls due to large french doors. Air return in there, and windows of last resort.