My First Attempt at Bowl Making

terrydowning · Post by **terrydowning** » Mon Feb 04, 2013 12:40 pm

What you are after is called Equilibrium Moisture Content or EMC. The point at which no more moisture will leave the wood due to surrounding conditions (Temperature, Humidity, Pressure, etc.) If there is a mill or other avid wood worker in your area they may be able to clue you in to a reasonable EMC percentage for your area. 2 scales come to mind. On smaller on kitchen type scale that goes to to a pound or two in ounces/grams and a hand held scale that ranges from a 1 to 30 pounds or so. Once the weight has stabilized, then measure with your meter and you will have have your magic percentage. I can't remember where I got my scale I used it extensively while a scout master to weigh backpacks. It turns out to be a very handy tool for weighing green blanks as well.

Another approach is to measure the moisture content of wood considered dry that has been in your shop for a while.

saminmn · Post by **saminmn** » Mon Feb 04, 2013 5:17 pm

terrydowning wrote:What you are after is called Equilibrium Moisture Content or EMC. The point at which no more moisture will leave the wood due to surrounding conditions (Temperature, Humidity, Pressure, etc.) If there is a mill or other avid wood worker in your area they may be able to clue you in to a reasonable EMC percentage for your area. 2 scales come to mind. On smaller on kitchen type scale that goes to to a pound or two in ounces/grams and a hand held scale that ranges from a 1 to 30 pounds or so. Once the weight has stabilized, then measure with your meter and you will have have your magic percentage. I can't remember where I got my scale I used it extensively while a scout master to weigh backpacks. It turns out to be a very handy tool for weighing green blanks as well.

Another approach is to measure the moisture content of wood considered dry that has been in your shop for a while.

Were Fred lives, he needs to keep the bowls inside cause they would change shape a lot if his shop is out in the 90% humidity of Houston and they were then brought inside:D

terrydowning · Post by **terrydowning** » Mon Feb 04, 2013 7:43 pm

Agreed!

We as woodworkers need to be familiar with the concept of acclimatization.

fredsheldon · Post by **fredsheldon** » Mon Feb 04, 2013 11:19 pm

Ok, I got a scale and weighed all three pieces. 2.7 lbs, 2.6 lbs and 7.89 lbs. I didn't take them out of the sacks. I have them packed with wood shavings and sawdust. Will the moisture depart the wood if I have the sack taped closed? Or do I need to poke some holes in the sacks.?

dgale · Post by **dgale** » Tue Feb 05, 2013 8:27 am

Assuming you are using brown paper bags (ie paper grocery bags), I assume the moisture will escape just fine through the paper. It's a matter of osmosis as moisture from within the bag seeks equilibrium with its surrounding environment. Remember that osmosis involves a movement toward equilibrium through a semi-permeable membrane (in this case your paper bag). You want this occur slowly to limit checking but not so slowly that mold forms. Opening the bag would accelerate the process more than is likely ideal, whereas using something less permeable would slow things down too much and potentially lead to mold. Patience is presumably the key here.

pennview · Post by **pennview** » Tue Feb 05, 2013 8:41 am

Your blanks are in paper bags, right? If so, taping the bags is no problem.

Just keep a log of how things are progressing, so you can apply that knowledge to the next round of drying. This isn't a scientific process and you'll need to adapt your procedures as you go along. The saw dust and shavings will slow the process, which basically is the whole idea, lest they dry to quickly and crack. This also will help in determining how thick the walls of your bowls ought to be in order to turn them round again after the drying.

This publication by the Forest Products Lab on air drying lumber may prove useful. It contains a chart on dryness levels around the country by month, which should give you an idea about how dry you bowls are likely to get -- http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr117.pdf

fredsheldon · Post by **fredsheldon** » Tue Mar 19, 2013 9:59 am

No 7 in the bag is from Bodark wood. It was given to me by a co-worker and is supposed to be green but it's hard as a rock to turn. It's also a vivid yellow. It will be interesting to see how it looks when dried and finished.

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I wonder what color this wood will be when it dries and is finished. I have enough to make 3 more bowls.

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My chip/shaving containment system in action.

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Bright yellow shavings from Bodark tree log.

terrydowning · Post by **terrydowning** » Tue Mar 19, 2013 10:54 am

Lookin' good Fred!

Bodark from Bois d'arc (AKA Osage Orange)

from Wood Database

Color/Appearance: Heartwood is golden to bright yellow, which almost certainly ages to a darker medium brown with time: primarily due to exposure to UV light. See the article Preventing Color Changes in Exotic Woods for more details.

fredsheldon · Post by **fredsheldon** » Thu Apr 11, 2013 10:01 pm

First 2 bowls out of the bags that have been drying since January. One has a small crack, the other is crack free. I still have a lot to learn about style and finishes.

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Crack free

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Small crack that I filled with CA glue to stabilize. I was planning on performing the final turning but it warped too much so I just sanded it and called it finished. The walls are thicker than I wanted. I think I will turn future green wood down to the final thickness and take my chances with cracking if they are going to warp bad enough that I can't finish turning.

terrydowning · Post by **terrydowning** » Fri Apr 12, 2013 10:55 am

Patience pays off Fred.

Nice job.