how to find out about an unfamilar wood

[BlueRider]

A friend was asking me about a wood he is unfamiliar with. We have a lot of sorces for identifying the trees but very little info on how suitable these trees are for making into lumber. This is the procces I use in evaluating woods I am unfamilliar with and I thought others here might be interested in the info.

When I investigate a wood I am unfamiliar with I like to choose a limb that is about 8” in diameter and about 14” long. I cut it in half length wise with my chainsaw and then take it to my band saw and mill it into 3/8” thick boards. This will give plain sawn, rift sawn, and quarter sawn boards. I then take several boards and dry them one at a time in the microwave. I do this one board at a time in 2 minute intervals and for the first several cycles I stop the microwave before the cycle is up. I watch for the steam and bubbles and if it gets to be too much I stop the microwave. A little steam and bubbling is ok and once you let one cycle too long you will develop a feel for it. I turn the board between cycles using a pair of tongs. When you can make it through the 2 minutes with no bubbles or steam it is dry.

The reason I said to dry several boards is one of the ways of evaluating a type of wood for its suitability for furniture is how close the ratio is between its radial and tangential shrinkage. You can do some controlled drying tests in an oven, measure with micrometers and then do a few calculations or you can simply dry a plain sawn and a quarter sawn board and compare the warpage of the two. If one stays flat and the other turns into a taco the ratio is not very close but if they both stay perfectly flat or nearly so then the ratio is close. This is a bit of an exaggerated test due to the microwave and the thinness of the boards so to get a feel for how much movement is acceptable or what it translates to in the wood you will use in your shop I would recommend doing this exercise with a couple of known woods such as walnut, cherry, or maple.

There is another value as well as shortcoming of this exercise. It can also tell you how much degrade to expect. But at the same time there are a few types of wood that do not like to be force dried. These will crack and split if you force dry them, so much so that you might think it a waste of time to mill a whole log. Yet if you air dry the wood it dries just fine. Macrocarpa is a wood that can behave this way. This is a good exercise but not a tell all and end all test of a woods usability.

Another useful aspect of this exercise is that by using a pair of heavy gloves you can remove the partially dry and hot board from the microwave and bend it. If you bend it until the fibers on the outside of the bend tear or the fibers on the inside of the bend collapse you will discover how subtle that wood will be for steam bending.

About now SWMBO is giving you the evil eye and sorting through the kitchen knives. Take your dried boards back out to your shop and cut one into a nice spatula shape. Sand it and finish it with your favorite food safe finish. I tend to use Howard’s feed and wax. This will be your ticket to regain microwave privileges. If you put it through repeated dishwashing cycles it will also tell you how suitable that type of wood is for exterior use.

 

[BobL]

Thanks for the info BR - I must try this with some unusual woods around here some time.

 

[mikeb1079]

very interesting stuff. i'll have to try this out sometime. on second thought, i'll have to do it soon before we get a new microwave.
hey bluerider, what unusual or non traditional wood have you found to stand up to these tests and be suitable for furniture etc? and which have failed? just curious.

 

[rarefish383]

Could have bought a dozen used micro's at the sale yesterday for a buck each, Joe.

 

[BlueRider]

very interesting stuff. i'll have to try this out sometime. on second thought, i'll have to do it soon before we get a new microwave.
hey bluerider, what unusual or non traditional wood have you found to stand up to these tests and be suitable for furniture etc? and which have failed? just curious.

I think the first time I tried drying anything in the microwave it was a small piece of monterey cypress and the first time I tried milling and drying a small branch it was with siberian elm. This would have been back in the mid 1990's. I had read that elm was used in boat building but had never seen any at the local lumber yard so I knew nothing about it. I have since micro processed chinese elm, black locust, lemon, holley, Jacaranda, mullberry, acacia. And probably a few I have long forgotten.

When I started milling there were no web sites like this so I learned by doing. I could find all kinds of info on identifying trees but that was limited to the tree itself and had no info on the wood. I would read refrences to some woods having a history of being used for things like wagon wheel hubs or parts on wooden boats and that would spark my curiosity about that type of tree. Black loacust is a good example of this. I had read it was sometimes used in wooden boat building as well as being popular for fence posts and then noticed there was a bunch growing around town.