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alcohols as drying agents (Long, & ?boring)

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alcohols as drying agents (Long, & ?boring)

#1

alcohols as drying agents (Long, & ?boring)

Arch

>Denatured ethyl alcohol is currently of much interest to woodturners as a green wood drying agent. I thought to add some info from reading a dermatology textbook about another alcohol that may be of interest to some here. Glycerol (glycerin, glycyl alcohol) is made by combining a fat with water. It is colorless and odorless with a sweet taste and is syrupy at normal temps.

Glycerin is much used as a skin lubricant and moistener in soaps, cosmetics and emmolients. It _appears to moisten the skin, but actually dries it by bringing water from the deeper layers to the surface. I don't know if all alcohols share this internal drying characteristic, but isn't this just what we want for drying green wood?

I'm chemically naive (illiterate?) and I'm not suggesting that we use glycerin to dry our wet timber. I just thought the semblance between ethyl alcohol that dries wood and glycyl alcohol that dries skin is interesting. I wonder if glycerin is in some dish washing detergents but not all. Could that account for the disparity in effectiveness of different brands? Who knows? I sure don't!

Turn To Safety, Arch

Re: alcohols as drying agents (Long, & ?boring)

#2

Re: alcohols as drying agents (Long, & ?boring)

JL work

>Glycerin (glycerol) is more appropriately is known as 1,2,3-propanetriol. It has a "backbone" of three carbons with three hydroxyl (alcohol) groups hanging off of this backbone. It is very thick and does a reasonable job of absorbing moisture. It is not formed made by combining a fat with water. Most of your fats consist of a glycerol molecule with one or more fatty acids linked to the hydroxyls of the glycerol by an ester linkage. You can have a monoacyl, diacyl or triacyl glycerol (acyl is used as the generic name of the fatty acid).

Glycerol would absorb water nicely. The only problem would be how to get rid of it from the wood. The shorter chain alcohols such as denatured alcohol (ethyl alcohol or ethanol) also act as agents to "solvate" or draw off the water. As ethanol has a relatively low boiling point and a much higher vapor pressure than glycerol (meaning it evaporates much more easily), it will evaporate from the wood. Glycerol would not.

Re: alcohols as drying agents (Long, & ?boring)

#3

Re: alcohols as drying agents (Long, & ?boring)

John Lucas

>Wow that makes my head hurt. Interesting however. John

Re: alcohols as drying agents (Long, & ?boring)

#4

glycerol/glycerine dehydrating

Shawn - in ID

>Hi Arch, JL pretty much said it. I use glycerol to make tissue go clear. Some biological tissues will actually 'disappear' in glyceral - the reason has to do with refractive index and bending of light (not necessary here). Oil does the same thing - this is why oil soaking helps to make thin turnings nearly translucent. Bottom line is that glycerol/glycerin is more expensive, won't penetrate wood nearly as fast as ethanol, nor will it displace the water inside as efficiently, then of course you have the problem of getting it out of the wood since you can't finish nicely over it.

Re: alcohols as drying agents (Long, & ?boring)

#5

Re: alcohols as drying agents (Long, & ?boring)

Wood Spinner

>JL

You sound like the guy to ask about CA accelerator. Can I make my own cheaper than I can buy it?

I know about using water etc. but they don't work as well as what I buy.

Thanks

Good turning and be safe

Bill

Re: alcohols as drying agents (Long, & ?boring)

#6

Re: glycerol/glycerine dehydrating

Arch

>Using glycerin to dry wood was not my point. I just thought the semblance between it and denatured ethyl alcohol and an explanation for their drying skin and wood interesting. For all I know monacyl, diacyl and triacyl are dinosaurs roaming about in Juriassic Park. :)

Turn To Safety, Arch

Re: alcohols as drying agents (Long, & ?boring)

#7

Re: alcohols as drying agents (Long, & ?boring)

J L

>Cyanoacrylate adhesive contains a mixture of "prepolymers" and monomers and a stabilizing agent. The "activator" is really a neutralizing agent for the stabilizing agent. Water acts as a neutralizing agent due to its "amphoteric" nature (both a weak base and weak acid). I am reluctant to recommend any particular compound. You can try two things. Water with a little ammonia or water with a little vinegar. Don't use too much.

Re: alcohols as drying agents (Long, & ?boring)

#8

Re: alcohols as drying agents (Long, & ?boring)

Greg in Oshkosh

>Most CA glues use a base as an accellerator. A little ammonia in water works. (baking soda etc too)Most commercial accellerators use an organic solvent plus an organic amine (to provide the base) and the solvent doesn't swell wood fibers and rough up your surface like water.