Is 18% moisture content too high?

[Jerry Ingraham]

I have a fair sized blank of spalted maple which I rough turned yesterday. i checked it with my moisture meter and it's at 16%-18%. I went ahead and dumped it in the dna and will dry it for a couple weeks but was that necessary? Is 16% low enough that it will remain stable and not crack or does it need to be below 10%?

[Keith Burns]

18% is too high. Wrap and set for a week or two. It should be around 8% before finish turning..

[Jerry Ingraham]

I was pretty sure that was the case, that's why I went ahead and dna'd it. I recently got a moisture meter and thus the question. Left to my old way of determining moisture content ("these shavings feel kinda moist"), I would have soaked this blank as well. I guess instincts are pretty accurate afterall .

[Richard Madison]

Keith,
Do you think it will get to 8 percent just sitting in Yakima? Maybe 12 is more realistic? Am no expert. Just asking.

[Keith Burns]

Keith,
Do you think it will get to 8 percent just sitting in Yakima? Maybe 12 is more realistic? Am no expert. Just asking.

Richard, I know that furniture makers use KD wood at about 6%. Here in Tennesse where it is very Humid I will reach 8-9% easily. I think 8% is a traget but if you get to 9% for 2-3 days thats probably all the dryer its going to get. DNA drying time varies with wood species and location. I do consider 12% too wet to be stable. These are my opinions and we all know that opinions can vary

[Richard Madison]

Keith,
Thanks for your reply. Had no idea stuff would air dry to 8-9 percent in most areas. Always thought about 12-14 was the limit. Must go look at the book some more. I use KD wood in my segmented stuff and it sits in the shop for some weeks to equilibrate before use, but have no idea what its moisture content is when used.

[charlie knighton]

just my opinion:

different form require different moisture levels
a bowl would require 8% moisture levels while hollow form 20 to 25% moisture level

[George Van]

Here in northern WI I cannot air dry below 11% without bringing the wood into a controlled environment which is heated to reduce the relative humidity or dehumidified with a mechanical source to lower the relative humidity. These readings are taken with a Wagner pinless moisture meter and the oven dry method. In the winter, indoors, I can get 6%.

[Jerry Ingraham]

Lest there be any confusion geograpically, Yakima is in eastern Washington and is a very arid climate. Sage brush covered hills surround us. I have never had a problem reaching 8% mc so I'm gonna let this blank sit rough turned and wrapped for a couple weeks and I'm betting it'll be pretty good.

[Henry Cavanaugh]

a bowl would require 8% moisture levels while hollow form 20 to 25% moisture level

Charlie
I would but interested why bowls need 8 and hollow forms 20-25.

[charlie knighton]

i am not too good on the why besides the hollow form structure holds it true

i use a dishwasher to dry hollow form blanks to 20 to 25% moisture level, start out at 80 degrees for 2 weeks and progress 10 degrees 2 days at a time up to 120 degrees

in the american woodturner magazine summer 1998 Darrell Rhudy has an articule about dry kiln

also russ's corner: a woodcentral archive talks about using a dishwasher
article from 6/21/2006

Wilford O. Bickel pointed out the articles and I had several email conversations with him, he was very helpful.

i guess most turners rough turn, dry in some manner, then finish turn
i am still a new turner but drying the hollow form blank to 20% moisture content and finish turn it seems to work for me, i do not have any forms that are over 6 months at this time, i will like to see them 5 years from now

wood has 3 dimensions, verticle(long grain), radial (center to bark), tangential(around the growth rings)

wood shrinks in the radial and the tangential directions not vertical
i turn endgrain or vertical, with no pith

wood info thanks to hockenbery post on 7/29/2006 on aaw site

then turn

the bowl form does not have a structure at the top and will warp unless at about 8%