Official Luthiers Forum!

Here's one for the Chemists (or Geologists) out there:

Has anybody used a standard salt solution to control humidity? In theory this should work, I'll explain;

For those who don't know what a standard salt solution is - it's an aqueous (water based) saturated salt solution. Basically just a quantity of water with a bunch of salt dumped in it so that there's more salt there than will dissolve in that much water, it's now saturated.

In an enclosed area the humidity will be limited by the evaporative rate of the exposed solution at a given temperature. For pure water the RH would be around 100% at 25 deg C, but depending on the type of salt added to the water, you can lower the RH to a known level. For a saturated Potassium Carbonate solution you'd have a RH of 43.something% at 25 deg C. There's a list of various salts that will give various RH, they're known as standard salt solutions, and are how scientists used to control RH in their experiments before some bright spark invented expensive electrical gadjets to do the same thing.

So I'm thinking that a largish, shallow plastic tub half filled with water and with a couple of pounds of Potassium Carbonate dumped in it with a small electric fan mounted over the tub, should be capable of controlling the humidity (providing the temp is kept at 25 deg C) in a small room, or a couple of tubs with fans in a larger workshop should be able to control the humidity for a fraction of the price of these humidifyers/dehumidifyers that I've been looking at buying. Mount them and their fans on nice sturdy shelves up near the ceiling, and top them up with water occasionaly and presto: 43.something% RH controlled environment.

So, anybody tried it? Heard of it?

That's the way it used to done in labs whe I started at university back in the 60's, I hadn't thought about it for shop control! Neat!

We don't tend to have a problem with large humidity changes here so I've never felt the need to try and control it, but I'll give this a try. Even at a lower temp it should still act as a control albeit at a different RH. Science rules! In fact with a mixture of salts in varying proportions you could hold RH at any level at your selected temperature.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

What a great idea. By the way, reminded me that when I played clarinet, we used to put piece of orange peel in the case to keep wood humidified. Wonder if half a grapfruit rind woul work in guitar casses?

[QUOTE=bob J] What a great idea. By the way, reminded me that when I played clarinet, we used to put piece of orange peel in the case to keep wood humidified. Wonder if half a grapfruit rind woul work in guitar casses?[/QUOTE] Apples in the assesories box. I use to do it when I was travaling a lot.

I have seen people in Brasil mount a couple of spot lights above the work bench and have bags of silica in the wood stack to control humidity. It sure gets hot when working on a summer day though!!

Apples, grat idea-can also use as snack enroute! Topped with peanut butter.

Apples and peanut butter!? Really?

[QUOTE=Roy O] Apples and peanut butter!? Really?[/QUOTE]

You're kidding, aren't you!

The only thing better is bananas and peanut butter. Yummmm!

Steve Brown

Ya'll have it all wrong. Its sweet pickles and peanut butter

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Don Atwood
Arlington, VA

[QUOTE=Don A] Ya'll have it all wrong. Its sweet pickles and peanut butter [/QUOTE]

Now THAT is obscene!

Steve Brown

[QUOTE=sfbrown] [QUOTE=Don A] Ya'll have it all wrong. Its sweet pickles and peanut butter [/QUOTE]

Now THAT is obscene!

Steve Brown[/QUOTE]

If you guys don't watch out, this place is going to be so obscene that it'll be blocked at my work.

REALLY, It tasts great!! Chunky is best. I use Pink Lady or Johnathan (when in season).

I'm throwing in my vote for bananas and peanut butter.....on a sandwich!!

I give in.

It's bananas and peanut butter and honey!

Come on fellas, wheres the spirit of adventure-danger?

Peanut butter and 'nanna sandwiches are best enjoyed while wearing a sequined cape...don't ask me how I know, just trust me!

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http://www.presnallguitars.com