Drying Wood
The aim of drying wood samples is either to get a sample that can be ground to a high surface finish and/or to conserve the wood.
Drying "the natural way" sometimes results in twisted wood where dimensions have afterwards been severely changed.
By using solvents you may get a much faster drying process during which the dimensions of your sample will not change too much. Here are some ideas that can be useful for a beginner on doing this.
When you try to dry wood, think "how to remove water?"!
One way is using solvents.
The principle is then to replace the water with a solvent that is easier to remove afterwards than the water. E.g. first replace the water with ethanol and then let the ethanol disappear through a "drying process" which is faster than letting the water air-dry directly from the wood.
Three solvents are often used for this: alcohol, acetone, ether.
Water and alcohol are completely soluble in each other, and nearly absolute alcohol is hygroscopic which means that it probably extracts water from the sample. The same is true for water and acetone, but acetone dries up quicker. You may choose to use use either one of the two.
On the other hand, ether is not much soluble in water and has no hygroscopic qualities. But you could use ether, which dries up quickest, to replace alcohol or acetone once the water has been washed away from the sample.
Question: You say “nearly absolute alcohol is hygroscopic which means that it probably extracts water from the sample”. The label of alcohol that I’m using say “alcohol 96°; composition: ethylic alcohol 99,9%; Benzalchonium Chloride 0,1%”.
Answer: The label sounds dubious. 99.9 % is nearly absolute alcohol, 96 % is not (it contains 4 % water). Benzalchonium Chloride is a biocide and surfactant, why do you have it in the alcohol, it will probably remain in the dried samples? I think that 96 % alcohol should do the job, but 99.9 % will be faster. Though 96 % is cheaper as it is a natural azeotrope and can be made by destillation. Higher percentages require desiccants like zeolites which are quite expensive.
(By the way, you can save a cell phone which has fallen into sea water with a snaps. Keep it (in pieces) in a bucket with freshwater for some time, then shake off the water and put the electronic cards in a plastic bag with a shot wodka. After some more time, shake the wodka off and let the cards dry completely in the sun. Good chance that the phone will work after some time.)
Question: After the bath in alcohol the sample is drying much faster (and with almost inappreciable deformation until now) than other waterlogged samples. I can bought purer alcohol in a laboratory supplier store, but it’s more expensive. Can one estimate how long has to be the alcohol bath? I suspect I’ve not replaced all the water in the sample.
Answer: You could exchange the alcohol one or two times. And wait to let the solvent do its job, of course. There is an equilibrium forming between the water in the sample and the water in the solvent. There is no way to get more water out of the sample as there is in the solvent. Instead of using a vacuum drier you could use a glass bottle with some desiccant in the bottom to get the samples really dry. Much cheaper! The desiccant can be regenerated (be careful though , the solvents used are highly flammable!).
Question:
Rosin is sometimes named in relation with these drying operations - what's that?
Answer: Rosin (or some other resin) is soluble in alcohol too and used to "fill" pores in the wood, glue it together. It will of course make the sample unusable for C14 dating, as any other glue will do.
One suggestion if you want to enhance the surface of polished samples: apply a thin layer of furniture polish or white (bleached) shellac in alcohol. But make an experiment with a less valuable sample first! And do not use the wood for C14 dating afterwards!