Further Drying & Storage

So you wood has now dried to about 15 to 18% outside. Well it is not going to get get much drier than that, it will stay like that for years, providing you keep the stack dry - If you are going to use the wood for outside projects, then it is in the perfect condition, just use it from the stack. There is no point in drying the wood to 6% for outside projects, it will only increase in moisture content again once it is brought outside.

 

If, like me I want to use it for furniture making, then I have to dry again, this time under more controlled conditions.

My workshop is not so large, but I have taken ¼ of the space available and dedicated this to drying and storage of timber.

To try and maintain the humidity to constant level in the workshop, I use a dehumidifier, nothing fancy, just a general household version costing about 150€. This is running on automatic and is set to 40% RH, this also produces a certain amount of heat. To assist in the drying process, I employ a general fan, just to circulate air- this enables me to keep the lumber inside the shop at about 7 to 8% MC (Moisture content).

As the wood in this rack is all very dry, there is no advantage to using sticks between the planks, it would be very difficult to do and and would halve the space available for dry wood.

 

 

So you know want to dry your wood inside, basically it is just a repeat of what you did outside, but now you have the control over the environment.

Heating the air alone will help to reduce the MC in the wood, and of course you will need the air to pass over the damp wood, this will help to dry the surface of the wood, allowing more moisture to come to the surface.  If you can combine the previous to treatments with some method of extracting the moisture out of the air (eg. dehumidifier), then you are onto a winner.   You can of course scale down the size of the environment you are drying the wood in and create a big box, with Heat and dry air circulation - this maybe quicker and cheaper (less electric costs) than the method I use, I have not tried this yet, so I cannot comment at this time.

Remember that when you bring your wood inside, you are bringing water inside as well, so the humidity of the room/environment will rise (watch out for your precious dry stock).  although the wood you bring in will be about 15 to 18%, it is till prone to movement until it dries to about 6% - so you still have to place "BALLAST" on top of the stack to keep it flat.

 

The stack of wood you can see here is Finnish Oak (not very common no far north) A customer cut this tree down 3 years ago, but only milled the lumber this year {May 2008} (0.7m³/300bf). He approached me a few weeks ago and wanted me to turn his tree into furniture for his new house.

Most of the lumber was 30 to 40% MC (July 2008). We could not wait for the lumber to dry naturally outside for 2+ years, so I brought the Oak inside to dry it. The dehumidifier has been turned on to max and the fan speed increased to increase the air circulation.

For the first couple of days, the humidity in the storage room was in the 50%+ range, but after a week it is back under control and down to 40% RH. I am currently removing about 10Ltr (2 ½ gallons) of water a day. After a week the MC in the 12/4 lumber has gone from 40% down to 27%. I estimate about another 8 weeks and it should be ready to use.

{update Oct 2008.  the rate of water removal has now decreased to about 1 ltr a day.  the 1st projects with this wood are now nearing completion}

This photograph shows the timber samples I use for measuring the moisture in the wood. Over the years that have been proven to be quite representative of the timber stored in the racks usually within ±1% MC.

Species I have in stock are: White Oak (USA & EU), Ash, Black Cherry, Pine, Fir, Alder, Aspen, Birch, Beech, Black Walnut, Maple (Hard & Soft), Mahogany, Iroko, Jatoba, Purple heart, Teak, Finnish Oak (very different to red or White Oak), Bird Cherry (Tuomi) and always on the lookout for different species to add to the collection, big or small

To summarize, Keep it FLAT & Keep it DRY.

So this concludes my mini series of blogs on Lumber cutting and drying.  I have only just scratched the surface of this topic, but with the use of the Internet, good books and fellow woodworkers, I am sure that if you want to try this, whether its a log from the wood pile or a neighbor's tree that has fallen down, you will appreciate the difference and the pleasure from knowing that you have made something, that involved every process of woodworking from the tree in the ground to the finished product. 

I hope you have enjoyed it and found it informative.

Tags: lumber, lumber storage, drying

Categories: General