March 15, 2017

Drying Wood

Like many if not all wood turners I often get lucky and am able to turn green wood. Of course this means that we need to find a way to get it dry after we either rough turn it or turn it to finish. Sometimes I turn hollow forms so thin that they are almost dry when I finish but more often there is still some moisture that needs to be removed without the piece cracking.
Some turners let it dry by gradually allowing exposure to the air by many means such as bagging, boiling, putting in shavings, setting on the floor and gradually moving them higher in the shop. Most of the methods take a while and we really want to hurry the process.
Most turners agree that if the inside of a piece dries faster than the outside the wood tends to sort of compress and limit cracking. Some people wrap with the outside with plastic wrap, some coat with paint or a wax in emulsion. This lead me to my new method.
This winter has been pretty damp with lots of snow and rain and we were often drying boots and runners etc with a relatively cheap ‘Boot Dryer”.

The one I have is adjustable as to time it runs and has the option of using heat or not.
By adding hollow sections of plastic pipe etc to allow the air to get into and circulate inside the bowl or hollow form the drying process is sped up.

I am not a scientist and have a very limited knowledge of it’s principals and as a result I am unable to actually quantify the results of my method. All I know is that pieces treated like this tend to dry in about half the time of pieces left on their own.
I have only been trying this with fairly thin hollow forms and bowls that I will return to the lathe to sand and finish.
I have no experience with twice turned pieces dryed with this method.

By using the weight of the item I now am confident that the pieces I dry this way dry twice as fast as they do if just left to dry on their own.

I now have a little more information. The week before last I used my boot dryer to dry some small fairly thin bowls made from Gravenstein Apple wood and again the wood dried about twice as fast as a piece I left on its own and I had no cracking. At the same time I dried a small cup shape, it can be seen on the other blog (https://woodbowlsandthings.wordpress.com/2017/04/17/gravenstein-apple-wood/ ‎) about Apple it was dyed and then sanded. I sort of messed up as I didn’t manage to get the bottom as thin as the rest and after about 12 hours on the dryer I noticed some small cracks on the inside. I stopped using the boot dryer and the cracks mostly closed up and never made it to the outside. d

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