Question......

[Odie]

I normally rough bowls within a month or so after receiving the block when the moisture content meters above 14%. If the MC is 14%, or below, I'm in no hurry. I've got bowl blanks that were 14%, and below, that I've had for 7-8 years and there's never been any problem with these.

Not a rigid rule, but bowls that are roughed with a MC higher than around 20% on up to high thirties tend to be the ones that have the most warping.....some do, some don't, and species/grain pattern/burl, etc. all have their influence on which ones do, and which ones don't.

My question is: Is there anyone who chooses to leave bowl blocks (sealed) on the shelf for a period of time (years?) to reach a certain MC before roughing? If so, what amount of MC would be where you'd draw the line? I realize this number might vary, because the elements of that equation may vary......but, is there a general cut-off point where you'd make that decision?

Of course, I realize the interior of a block of wood may/will be entirely different than the surface, so the denseness of the species may play a more influential part of the decision making process, as well.......

ooc

 

[Bill Boehme]

The sooner the better for me! I have turned some within a day of cutting them down. I sure got a bath one time when I did this in early spring, but it was fun.

 

[Odie]

The sooner the better for me! I have turned some within a day of cutting them down. I sure got a bath one time when I did this in early spring, but it was fun.

For everything over 14% MC, this has always been my thoughts as well.

Maybe I should rephrase this.

If you're paying as much as $150 for a single bowl blank, is there a point where it would be better to suspend roughing until the blank reaches a certain level of MC in order to decrease the possibility of losses due to cracking and warping?

If so, where would be that point of decision?

20%, 25%, 30%, 35%.....? 😕

ooc

 

[hockenbery]

Odie,

If I have a nice piece of wood I can not turn in a short time I wrap it in plastic an put it in the freezer.
To keep it "wet"

At 14% the wood is basically dry so it is not wet wood.
So you won't have much warp because it has already warped.

Successfully drying bowl blanks is very difficult and will have a higher loss than Drying rough outs Which is easy.
Core them and you can be drying 2-4 rough outs.

I don't see and advantage to drying blanks.

If I had an expensive blank I would turn it or freeze it.
I would not want it to crack sitting on shelf.

Al

 

[MichaelMouse]

If you're paying as much as $150 for a single bowl blank, is there a point where it would be better to suspend roughing until the blank reaches a certain level of MC in order to decrease the possibility of losses due to cracking and warping?

If so, where would be that point of decision?

20%, 25%, 30%, 35%.....? 😕

Depends on the relative humidity and the grain in the wood. ~30% moisture is saturated, and shrinkage is pretty well linear there on down to the 10% that would be a comfortable human habitation number (55% RH). At twenty percent, you're down to half the total anticipated warp, so turning to twice the final thickness on most pieces and delaying three-five days is going to be enough. Impatience goes to microwave. If you live in the high desert, go down to 5-6% (25%RH). As we know, the best way of determining readiness is to weigh and re-weigh at five days. Then consult the hygrometer.

Then re-true. Since I don't care to try and work around the headstock, I make sure I can mount the conditioned blank bottom out first.

 

[robo hippy]

I read once that if you let the block sit for very long, the color is not nearly as bright. This means that if you get a couple of blocks from a fresh cut tree, and turn some right away, and leave the others, the ones turned right away will look better. I did experiment with this a bit and found out the difference is pretty significant. Mostly, I think the wood starts to decay/decompose/break down, like all living things do when it is cut down. If you allow the blank to sit, this is what it does. Putting it in the freezer may halt or slow down the process.

robo hippy

 

[hockenbery]

I read once that if you let the block sit for very long, the color is not nearly as bright. This means that if you get a couple of blocks from a fresh cut tree, and turn some right away, and leave the others, the ones turned right away will look better. I did experiment with this a bit and found out the difference is pretty significant. Mostly, I think the wood starts to decay/decompose/break down, like all living things do when it is cut down. If you allow the blank to sit, this is what it does. Putting it in the freezer may halt or slow down the process.

robo hippy

Totally agree....
Color loss is a major consideration. Easily seen in the Sapwood which begins to discolor in a few days.
freezing will preserve the color for years.... Be sure to wrap blanks you freeze in heavy plastic or you "freeze dry" the wood and it will crack.

Al

 

[Odie]

Thanks for all the responses. I've pretty much always immediately roughed anything above 14% MC, so I've not been aware of the discoloration. Interesting......I'll have to keep that in mind. Thanks. I am aware that certain woods, like Padauk and Osage Orange do discolor with age, and it's not dependent on how long the original bowl blank stayed in block form.

I think everyone, so far, is still missing the intent, or point of my question........🙁

I'll try once more.......

My intent is not to "season" a bowl blank in block form, but asking if at any specific level of MC, it might be best to allow a bowl blank to partially dry to that specific level of MC in order to reduce the occurrence of loss due to overly warping and cracking. At that point, the reduced MC block would be roughed as usual, and seasoned as usual to the point of MC stabilization. After stabilization has occurred, it would then it be finished turned to the final shape, as usual.

The object is to reduce the MC to some specific point, in order that the roughed bowl will have a specific pre-determined amount of MC at the time it is roughed. I'm enquiring to see if anyone has done any experimentation with this concept, and has knowledge of what level of MC works best prior to roughing.

I'm surprised that nobody has responded who might have experimented with this theory, and supplied the conclusions he found. That point might be 30%, but it might be more, or it might be less......but, I really don't have an answer, because I've not done any practical experimentation myself......just "fishing" to see if anyone has considered this, and experimented with it.

Anyone?

ooc

(BTW, MM......
There are those woodturners, including myself, who feel using a hygrometer to determine relative humidity is an exercise in inconsequential data. The relative humidity in your shop, may not be the same as in your house, or someone's house across town, state, the USA, or the world......so the only thing that really matters is MC, and that it has stabilized at the location where it will be finished turned. This is still not a guarantee that either RH, or stabilization of MC will be the same anywhere else, but the lower, and stabilized MC is a far better indicator of the target objective than RH. Please start a new thread, if you want to discuss the merits of RH, and allow this thread to stay on topic......thanks.)

 

[MichaelMouse]

(BTW, MM......
There are those woodturners, including myself, who feel using a hygrometer to determine relative humidity is an exercise in inconsequential data. The relative humidity in your shop, may not be the same as in your house, or someone's house across town, state, the USA, or the world......so the only thing that really matters is MC, and that it has stabilized at the location where it will be finished turned. This is still not a guarantee that either RH, or stabilization of MC will be the same anywhere else, but the lower, and stabilized MC is a far better indicator of the target objective than RH. Please start a new thread, if you want to discuss the merits of RH, and allow this thread to stay on topic......thanks.)

Weighing determines equalization. The hygrometer tells you what the piece has equalized with. Simple. If you anticipate a more or or less constant RH other than that the one you have equalized for, you will have to modify under containment. Which, if you think about it, is also the answer to the question you have not asked prior to the last. You turn at the higher MC if it matches the RH anticipated for constant storage or display. How close is close enough? As the book says, shrinkage is linear, not logarithmic.

Moisture content, and questions of moisture content are questions about relative humidity. You obviously know that, because you reference future conditions in terms of RH. Makes the answers you have received on point, only the questions have wandered.

 

[Odie]

Weighing determines equalization. The hygrometer tells you what the piece has equalized with. Simple. If you anticipate a more or or less constant RH other than that the one you have equalized for, you will have to modify under containment. Which, if you think about it, is also the answer to the question you have not asked prior to the last. You turn at the higher MC if it matches the RH anticipated for constant storage or display. How close is close enough? As the book says, shrinkage is linear, not logarithmic.

Moisture content, and questions of moisture content are questions about relative humidity. You obviously know that, because you reference future conditions in terms of RH. Makes the answers you have received on point, only the questions have wandered.

MM.......

If I knew my bowls were going to be sold to a customer in Hawaii, or anywhere else outside of my local area, adjusting RH to that environment might make some sense. Since almost no woodturner knows where his bowls will end up, It makes no sense to adjust for any RH, except that which exists where he is.

It is also appropriate to realize that two homes on the same street, in the same town, may have different RH levels because they are controlled environments. If everyone left their bowls outside, then it would be different matter.

These things are why stabilization of MC, is the only thing that will give some assurance of longevity, no matter where his bowls end up.

ooc

 

[Mark Mandell]

Emc(2?)

Met a guy in Arizona who had this neat little furniture business. While he made a piece here-or-there, his primary shtick was re-gluing "Snowbird" furniture (people who had moved south) when the items' joints got loose after the wood shrank in the dry desert air.

I suspect that for a one-piece bowl you boys are arguing over nothing; more important issue for segmenters. Once a piece of wood reaches EMC in a given location it will stay that way as a function of its environment. It is a given that EMC changes with the seasons and the natural rise and fall of humidity in any given location. Finish a turning in July in Ohio and it will stabilize at 11-12%. Come January in Cleveland, it may be at 9-10%.

 

[Mark Mandell]

Ps

If you wish to know whether your wood has reached EMC [for your location], take your moisture meter and check one of your interior door jambs, wood wall studs, or even your workbench. When the reading on your piece matches the reading on the existing wood, it's done.

The simple rule is that all wood in a given location will have the same EMC, regardless of species or hardness.

 

[dbonertz]

Everyone is right with what has been said. Getting to your question I can only partly answer. In my part of Colorado we are lucky since we can put a log in the field in direct sunlight and it will be good for a long time. Some woods such as elm can be out there for 6 years or more and still be good once you cut the ends off a bit and you may loose 2 inches in from the outside of the log. I bring this up because although this wood is still wet inside it has dried quite a bit from where it has started. I have not really took a meter to know exactly where it is but I can tell by roughing it that it has dried a lot. I kiln dry blanks and I have not noticed much if any advantage to waiting versus cutting really wet logs right away. They kiln dry well both ways. The only advantage that I have noticed by waiting for some moisture to leave is handling the logs/rounds through the band saw stage. But I admit I have not done a very accurate or intentional study either.

 

[Dirk Hoogendoorn]

A lot has to do with ability and ambition as well

This spring we had a real big ice storm and I got a number of big chunks of Maple. After that I do need to get them cut up, but sometime the old boy was not up to it so it waited a little longer. We are very fortunate in that we have an abundance of forest in the area if the piece is no good then it makes fancy firewood.

 

[Bill Boehme]

.... take your moisture meter and check one of your interior door jambs, .....

So do you have a story to explain to the lady of the house about the mysterious appearance of pairs of tiny holes in the woodwork? 😉

Before I try this moisture test, I would like to have a tried-and-true "explanation" in my hip pocket. I thought about saying that it was fanged by a wood snake, but since she used to teach biology, that one might not pass muster.

 

[Mark Mandell]

So do you have a story to explain to the lady of the house about the mysterious appearance of pairs of tiny holes in the woodwork? 😉

Before I try this moisture test, I would like to have a tried-and-true "explanation" in my hip pocket. I thought about saying that it was fanged by a wood snake, but since she used to teach biology, that one might not pass muster.

Ah, sooo easy.

Start of the second floor checking the bottom sill of a north-facing window, move to the jamb nearest the waste vent stack, then to the front door, finishing with the basement rafter under the kitchen sink.

"What the **** are you doing poking holes in my woodwork?!!" (Note: it became "hers" after you refinished it, of course)

"Using this fancy tool I got to keep us safe from toxic mold, My Love. The meter will detect unusual moisture content in the leak-prone areas, so if they all read the same, we're safe."

Her response: "I knew there was a reason I married you. Thank you for keeping us safe. I think I'll go to bed early tonight . . ."

More questions?

 

[hockenbery]

So do you have a story to explain to the lady of the house about the mysterious appearance of pairs of tiny holes in the woodwork? 😉
.

I turn a lot of hollow forms on faceplates. I allow a 1/4 inch of wood for the screw hole to open ahead of the screw.

When turning off the bottom......
One tiny hint of screw hole is Easily passed off as a worm hole.
Two can be passed off as a pair of worm holes. 🙂


Three even to the ill informed are faceplate holes. :-(

I think two holes and a can of raid and you are all set.....

Al

 

[dbonertz]

Ah, sooo easy.

Start of the second floor checking the bottom sill of a north-facing window, move to the jamb nearest the waste vent stack, then to the front door, finishing with the basement rafter under the kitchen sink.

"What the **** are you doing poking holes in my woodwork?!!" (Note: it became "hers" after you refinished it, of course)

"Using this fancy tool I got to keep us safe from toxic mold, My Love. The meter will detect unusual moisture content in the leak-prone areas, so if they all read the same, we're safe."

Her response: "I knew there was a reason I married you. Thank you for keeping us safe. I think I'll go to bed early tonight . . ."

More questions?

Wow Mark, don't ever turn your wife a rolling pin. It may get used for more than you care.

 

[Mark Mandell]

D,

I made her many things over the past 44 years. A rolling pin wasn't one of them.

 

[Bill Boehme]

..... Her response: "I knew there was a reason I married you. Thank you for keeping us safe. I think I'll go to bed early tonight . . ."

More questions?

You are a silver tongued devil. 😀