Drying rough turned bowls quickly.

[Dave Smith]

I posted this on Woodcentral and expect a lot of discussion there. I will try to answer your questions here also.

Fred Holder was kind enough to publish an article I wrote about drying bowls in More Woodturning. I am not sure where you can obtain a copy of the November issue or if Fred has extra copies available for purchase. The process is something I have worked on for many years and it has proven very effective.

In the interest of turners who would like to turn bowls from green wood and give them for gifts this coming Christmas I am posting the process in a nutshell. Please let me know your results, good or bad, so I can write a followup article about the general use of the process.
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ALCOHOL SOAKING GREEN BOWL BLANKS IN A NUT SHELL.

Turn the bowl to a thickness of ½"for small bowls(< 6 inches). Larger bowls may need to be thicker to allow for distortion.

Place the bowl in a container of denatured alcohol.

Let soak for 2 or more hours.

Remove the bowl and place it on a rack upside down for 1 hour to let the surface dry.

Wrap the bowl in heavy paper such as a grocery sack. On a bowl simply gather the paper around the rim and secure with a couple turns of masking tape. On a closed form the paper can be tucked into the opening and held in place with masking tape across the opening. The opening must be open to allow air circulation.

Place the bowl upside down on a rack so air can circulate into the opening.

Record the weight and date on the bottom of the paper. When the weight stops decreasing it is ready to finish turn.
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Small bowls will stop losing weight in one week or less. Large bowls will take about two weeks. Hollow forms very in drying time due to the small opening which inhibits air exchange. It is not necessary to record the weight every day but initially you may want to check the progress to satisfy your curiosity. I keep my shop heated and dehumidified year round so my drying time may very from what you may experience.

Nearly every turning I have posted on this forum has been dried using this process. There have been some failures but they have been rare exceptions. So don’t use a priceless irreplaceable piece of wood to test this drying protocol.

I owe a big think you to the many people who helped me test the alcohol drying process during the past year and those who encouraged this project. They validated my findings, edited text and gave me the confidence to publish the results. In no particular order these people are David Propst, Bill Grumbine, Dominic Grecco, Jennifer Shirley, Mark Kauder, Larry Hancock, Scott Greaves, Sean Troy, Barb Siddiqui, Mike Schwing and Ellis Walentine.

Good luck.

Dave Smith

With a shop full of dry bowls in Longview, WA.

[Barbara Gill]

Dave, thanks for posting this. I will give it a try.

[Andy London]

Thanks, what is denatured alcohol, is that the same stuff you buy at a drug store? If not, where would one find it (generic type store as I live in Canada)?

Thanks
Andy

[Jason Roehl]

Thanks, what is denatured alcohol, is that the same stuff you buy at a drug store? If not, where would one find it (generic type store as I live in Canada)?

Thanks
Andy

Andy, around here, denatured alcohol is found at the Home Depot/Lowe's/Menard's-type stores. It is ethanol with a small percentage of methanol added (typically 3%) to make it poisonous so that it doesn't get taxed by the federal government and can be sold much cheaper. A gallon of it here costs roughly $8. Everclear(tm) (95% pure ethanol, 5% water) is sold as liquor, and is about $20 for 1.75L(~1/2 gallon) in comparison.

I use it with a charcoal chimney to light my grill--no petroleum distillate aftertaste, and all the methanol burns off so it's not poisonous.

[Andy London]

Thanks Jason, I have to go to HD this evening and will look for some.

Does this mean you don't have to seal the wood? Doesn't it split? I am very interested in this as Microwave drying is not working out so good, we are sold out of turnings buy have tons of green woods, mainly figured and burls....really desperate to fins a way to dry this stuff fast and am willing to try anything.

Rather than using a scale, may I assume I can use my moisture meter?

Thanks Again
Andy

[Dave Smith]

Hi Andy,

Dominic uses a moisture meter to determine when a bowl is dry. He reports that bowls have dried down to 6% in two weeks of drying in his house. Remember that dry is equilibrium with the surroundings. I used weight because it was easy and I don't have a moisture meter. Soak the bowls and wrap the outside with paper. Just make sure air can circulate around the uncovered inside. They should be dry within two weeks.

Dave Smith

Back to the football game in Longview, WA.

[Andy London]

Dave,

I have one further concern/question, since methanol is poision and we are soaking the wood in it, does that mean for example that the turned product would no longer be food safe?

Thanks Again!!

Andy

[John Shuk]

Will isopropyl alchohol work if it is 99% pure? I can get that by the gallon for free.

[Jim Becker]

I have one further concern/question, since methanol is poision and we are soaking the wood in it, does that mean for example that the turned product would no longer be food safe?

No, it flashes off. The "formula" it to prevent folks from drinking it as grain alcohol which is exactly what it is (200 proof) until the additive and a spot of water are added.

[Dave Smith]

Hi John,

I tried isopropyl but it stunk up my shop too much. I reasoned that the larger molecules would evaporate slower and put less stress on the bowl while drying. Normally isopropyl is available at 70% concentration which is optimal for germ killing. I think it will work. Free is a very good price. The few pieces I tried with isopropyl didn't dry any different than using ethanol. I didn't like the smell and I think it was more expensive.

Good luck.

Dave Smith

Don't like my shop smelling like the hospital emergency room in Longview, WA.

[Dave Smith]

Hi John,

Denatured alcohol is 90% ethanol and about 10% methanol to make it unfit to drink. The alcohol will evaporate off. Most people use denatured alcohol for cutting shellac and dried shellac is food safe.

Dave Smith

Keeping my shop well ventilated in Longview, WA.

[Andy London]

I'm clueless on this alchol stuff so please near with me. I went to the big box nd the only thing they have by the gallon is Menthol Hydrate, is that what I need..?

[George Tokarev]

I'm clueless on this alchol stuff so please near with me. I went to the big box nd the only thing they have by the gallon is Menthol Hydrate, is that what I need..?

Three peoples divided by a common language. Denatured alcohol in the US, methylated spirits in the UK, and methyl hydrate in Canada? Look at the ingredients list on the can. You want a high percentage of ethyl alcohol (ethanol) and a modest percentage of methyl alcohol (methanol). The term methyl hydrate suggests a watered-down methanol, which is not what you want, unless you're interested in discovering the meaning of the term "blind drunk." Methanol's more intoxicating and more poisonous than ethanol, which is why it's added to the latter in the US to avoid excise taxes. They're close enough in boiling point to make vodka-production difficult.

You might also want to look at the following before following this or the LDD bandwagon. http://www.hi.is/~joner/eaps/wh_haloo.htm

With the normal bowl orientation and a taper to the bottom, there is probably no point more than a half inch from open air through end grain on a 1" thick bowl. If a board will dry, by the old rule of thumb, one inch in one year, and the end grain loses moisture at a bit more than ten times the rate of face grain ... well you do the math.

Alcohol may help evaporate the unbound water, but it's not ionic enough to strip the bound water adsorbed to the fibers, so I'd spin up my blank to fling as much unbound as possible, set it in open air, and let it dry. Even in the maritimes, wood is going to dry more rapidly in heated areas, so what you do at 1/2" thick will certainly be turnable in a month. At 1/4 inch warp and go thickness, it's a week to unblushing lacquer.

[Dave Smith]

Hi George,

I am not sure what your point is with the halo reference. Also I could not follow the line of reasoning in the last two paragraphs. If you think the process I have suggested is a lot of hooey then just say so. I spent over three years perfecting the procedure and had several turners test it during the last year before publishing it.

Dave Smith

Not a math whiz but I can use a calculator in Longview, WA.

[Dave Smith]

Hi Andy,

The alcohol I use is about 90% ethanol denatured with methanol to make it unfit for consumption. Commonly used as fuel for alcohol stoves and a solvent for shellac. I guess I need to include the common names used for the same product in other countries to limit confusion in the future. Could you let me know what the product is called when you find it.

Dave Smith

Not a linguist in Longview, WA.