Alcohol Soaking

Welcome to my blog on alcohol assisted drying of wood. The intent is to provide an avenue for information sharing about the process. Much time has been spent answering individual emails from around the world and countless questions on many woodworking forums. As time permits I will share information about current pieces I am drying as well as the final outcome in the form of pictures of finished pieces.

Thursday, June 08, 2006

White Oak Bowl Drying Process

I turned this bowl from a tree I obtained the beginning of May 2006. About 11 1/4" in diameter.

Click on pictures to enlarge.


I turn bowls close to the pith as can be seen here. I have found that even if the pith area cracks it is going to be turned away when returing the rim. Even if I trimmed an inch from the pith when roughing out the blank, as most people suggest, the end grain edge will deform upward requiring further reduction in bowl height. I seldom ever have to trim the walls lower because of cracks extending from the pith.


The wall thickness is 3/4" and the rim is about 1" thick. The rule of thumb is to rough bowls to 10% of the diameter. Following that rule I would have turned the walls to 1 1/8". The rim is thicker because I plan to form a bead on the outside of the bowl to facilitate lifting it with one hand.


The bowl was placed in a 13 quart stainless steel bowl. No problem with green white oak it goes right to the bottom.


The cover I use is made by placing a heavy piece of plastic sheeting over the bowl then wrapping the rim with plastic shipping tape. By stretching the tape a reasonably tight fit is achieved. This is only the second cover I have made in five years.


After soaking about 20 hours the bowls was removed. The bowl could have been removed sooner but the longer soak time suited my schedule.


After allowing to dry for about one half hour it was ready for wrapping in a brown paper grocery bag.


After cutting the paper roughly to size it is helpful to tape down two sides to keep the paper in place while taping.


Gather the paper as you wrap tape around the rim.


Trim the paper to the in side edge of the rim.


Weigh the wrapped bowl and place it upside down on a rack to allow air to circulate inside the bowl.



A data card is not necessary but at least write the date, time , and initial weight on the paper. This will allow you to estimate when to start checking the bowl weight if you want to turn it as soon as possible. Most bowls are dry in about 2 weeks. I expect this white oak bowl to stop losing weight in 8 to 10 days.


My intent was to post this information the day the bowl was wrapped and set aside to dry. Then post the weight each day so turners could follow the progress. Life sometimes gets in the way of good intentions.

White oak from Red Lion Motel, Kelso, WA. Cut down 1 May 2006.
Diameter: 11.25"
Height: 3"
Wall thickness: 0.75"
Rim thickness: 1"
Recess cut in bottom for expanding grip with chuck jaws: 0.25" deep, 3.25" diameter
Bowl into alcohol solution: 1515, 06/01/2006
Bowl out of soaking solution: 1030, 06/02/2006
Alcohol percentage of solution:
Begin soak: 75.3%
End soak: 73.1%

Weight in grams.
06/02 - 1115 - 1490
06/03 - 0040 - 1366
06/03 - 0625 - 1324
06/03 - 1520 - 1250
06/04 - 1045 - 1198
06/04 - 2025 - 1176
06/05 - 0840 - 1144
06/06 - 0055 - 1112
06/06 - 0835 - 1106
06/06 - 2150 - 1082
06/07 - 0800 - 1072
06/07 - 2000 - 1058
06/08 - 0830 - 1048
06/08 - 2015 - 1038
06/09 - 0740 - 1026
06/09 - 2010 - 1016
Click on picture to enlarge.
The paper is very loose and the pith is hanging in there.
Picture taken 06/09/2030.
06/10 - 1015 - 1012
06/10 - 2145 - 1008
06/11 - 0905 - 1006
06/11 - 2145 - 1000
06/12 - 0905 - 997
06/12 - 2115 - 998
06/13 - 0815 - 995
06/13 - 2130 - 992
06/14 - 0930 - 991
06/14 - 2300 - 992
06/15 - 1330 - 991
06/16 - 1245 - 991
06/17 - 0715 - 989
06/18 - 0915 - 986
06/19 - 1400 - 985

White Oak bowl drying curve.
Click on the chart to enlarge.
The charted weight and time data yields a curve which is typical of an alcohol soaked piece. At this point the bowl weight will fluctuate with the shop humidity. I consider the piece dry and ready for turning. I will continue to record data for several days and up date the chart in a few days.

06/17/2006 - After 2 weeks the bowl weight is changing in relation to shop humidity. .

06/21/2006 - Removed the paper yesterday and took several pictures of the white oak bowl. There were three small cracks on one end of the bowl that do not go all the way through. My experience has been that the cracks will turn away.

The paper became very loose as the wood shrank.


Recess ovaled to 3 9/16" x 3 13/16"


Narrowest outside diameter is 10 5/8"


Widest outside diameter is 11 1/8"


Pith raised about 1/4"

Bottom distortion is less than 1/8"

Three small cracks on the outside wall of one end
My experience is that the cracks will be turned away.

5 Comments:

  • At 7:03 AM, June 08, 2006, Anonymous Anonymous said…

    Will newspaper work in place of the brown paper bag? The brown paper bags are becoming hard to come by.

     
  • At 9:49 AM, June 08, 2006, Blogger David R Smith said…

    Yes, newspaper will work. I will post an in depth answer to your question in the FAQ section later.

     
  • At 4:40 PM, June 21, 2006, Blogger Kevin Gerstenecker said…

    Ok, I know this bowl is worth more, but I am opening the bidding with $10.00. Thanks for the opportunity Dave!

     
  • At 2:17 PM, June 24, 2006, Blogger David R Smith said…

    Congratulations Kevin. You are the winner. I will email you the shipping cost later today.

    Dave Smith

     
  • At 4:21 AM, June 25, 2006, Blogger Kevin Gerstenecker said…

    Thanks Dave. I feel like a thief, getting this bowl for such a measly offer! I am sure I have something around here I can send to up the ante! ;-) I will get the funds in the mail as soon as I get your email. Thanks again Dave........I am looking forward to the challenge of finish turning this bowl. As you asked, I will document the process (with photo's too, that you can use as you see fit.) I think I better sharpen up the gouges for this one!

    Kevin

     

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