Drying and Processing Mulberry

A slow-drying wood, Mulberry requires special handling. May 18, 2010

This summer a client brought some mulberry wood to me to build counter out of. I measured the wood moisture content at 22% and told them it wasn't dried right. They took the wood to another kiln and brought it back to me after a month or so and I measured it at 14 - 16%, and I told them it was still too wet for furniture. Now they are wondering if it would ever be dry enough for furniture if they let it sit in a dry space over the winter. I don't think so, but - any ideas?

Forum Responses
(Sawing and Drying Forum)
From contributor M:
I have dried red mulberry and got it down to 6-8%. I also green turn bowls out of it, and they eventually get down under 10%. Sounds like the kiln operator needs to try at least one more time.

From Professor Gene Wengert, forum technical advisor:
You really need to try a new kiln operator, as you need 7% MC. It takes time in the kiln to achieve that MC with mulberry and apparently the kiln operator is not measuring the MC every day or so.

From contributor T:
How much mulberry is it? Mulberry usually is only available in very small quantities, less than 300 board feet, and the minimum amount the smallest kilns can accept is around 1,500, so I would assume the kiln operator stuck the mulberry in a kiln load with something else.

From my experience mulberry is similar to black locust and osage orange, so it is very slow drying and not comparable to much else, especially as far as kiln drying goes. How did this material get kiln dried? I imagine assuming this is a small quantity, you need a mini kiln, or a kiln operator willing to run a small full kiln cheaply just for your stash.

From the original questioner:
The total footage was about 200 ft. and yeah, the first guy put it in with about 4000' of other lumber. From the looks of it, he didn't stack it evenly because it came out completely twisted and checked badly. The second guy had a vacuum kiln and it was in there for a month or so. I successfully steered my clients away from the mulberry and towards mahogany.

From contributor T:
Mahogany is a big change from mulberry!

Mulberry will also produce the problem of drastic color changes. It will be orange to yellow when fresh cut, and if exposed to a lot of sun can turn a very dark burnt orange.

If you ever deal with mulberry again, I recommend air drying it to 12-15%, then bringing it into your shop or other indoor air controlled climate to further acclimate to around 8% or so. After the wood has reached the desired MC it should be skip surfaced, then left for a day or two, skip surfaced again, left for a day or two, then finally surfaced to the desired thickness, removing equal amounts off each side. This is called double or triple milling. This method is old fashioned and works very well when done properly, resulting in the flattest boards possible. I process all my finer grade woods this way.