Alcohol Drying of Wet Wood

You forgot the laminar flow analysis.

With all of the George bashing that has been going on, did anyone notice that in my post, that with all of the experimenting that I have done, that I haven't noticed any real difference in the drying methods? I am not saying that it, or any of the other methods don't word, I am saying that I can't tell any real difference. Some day I will have to do a more scientific testing. robo hippy

I just started a new test with the walnut root, except I cut the root in half and turned two small bowls with 1/2" wall thicknesses. I soaked one in alcohol for two hours and the other one I simply wrapped the outside with paper. Both are wrapped in paper with the inside of the bowl open to the air. The wood was extremely wet. I'll weigh them each day until they quit losing weight and then will report back with my findings. Their initial weight, weighed at the same time, was 215 grams for the unsoaked bowl and 225 grams for the soaked bowl. Incidentally, I noticed that you said you didn't notice any difference in drying with any of the various methods and that is why I decided to make a comparison test. I personally believe that the wood soaked in alcohol dries more quickly than wood that has not been soaked, maybe my test will show that I'm wrong or hopefully it will show that myself and a lot of other people are right about the alcohol soak. In any case, I'll report my findings in a week or two. You'll note that I'm using bowls for my test and not 1" cubes.

Fred Holder

Might have to start another thread for that one Fred, I should be turning next week, and will see if I can do the same thing with the LDD. robo hippy

Fred, The folks at Forest Product Labs expect you to find a difference. At least that's what I got form the excerpt I posted, that solvent drying is a valid procedure.

Dan

A 14 hour period is not much of a test, but between 5:00 pm yesterday and 7:00 am this morning the alcohol soaked bowl lost 25 grams and the unsoaked bowl lost

10 grams. This is the first time that I've checked two identical pieces (i.e., same wood) at the same time.

Fred Holder

Yes indeed. As you might have noticed elsewhere, people who are not intimidated by the alcohol "tailors" into holding their tongue in the presence of the emperor are having similar problems. You must use good procedure for good results, none of which has anything to do with ethanol.

My spouse, bless her soul, is fond of answering the question of "how's George?" with another question.

"Compared to what?"

So, here's a comparison to help answer the question as to whether there's anything remarkable in the decidedly skimpy "data" provided as conclusive evidence at the beginning of this thread.

My neighbor felled a cherry tree on the weekend of the eighth of April of this year. It had not yet come into bud, so it was certainly low in unbound moisture. We hauled it to my place the following Thursday, April 13, and I began turning from it that weekend. Yesterday, after posting my confirmation of evaporation data, and before the 911 difficulties began an afternoon and evening of festivities, I went over to the shelf where a half-dozen early pieces made of that wood were stored.

Pieces were roughed between 1"and 1 1/8" thick to allow for a bit of design change later as desired, placed on the table in a shop with 65% day, much lower during the heated night relative humidity until no dark spots from centrifugally expressed moisture were visible, then stored under the drill press near the floor. Locating closer to the floor gives an additional 10% RH, on average, bit more when heated air is dumped from above. I'm in no rush to dry them.

They were moved to their present location 3 feet off the floor and out of the shop so the Son-in-Law and I could make all the %$#@&!! mortises for slats in the king-size mission bed my daughter wants on the 5th of May, where relative humidities are in the high 60s or even higher still (75-80) the last ten rainy days.

How have they fared? Average of 16% at the moment, measured at the worst place, the bottoms they're resting on. This compared to the best case EMC of 14.3 for 75% and 65 degrees - the current averages. Had they been thinner, of course, they'd be as dry as they can get in this humidity, since doubling the thickness triples the dry time. They'll be final turned at

9-10%, for 50% RH/70 degrees when the dehumidifier comes on line if I need their variety and size for late summer shows, or in the fall.

As to distortion, it's safe to say that this is as poorly understood as chemistry among some. Anyone who studies wood knows that distortion is related to the interval, orientation and curvature of the annual rings, and the relative density of the early and late wood. This tree grew pretty evenly, with an average of more than an eighth of an inch between rings, and the pieces were cut on average an inch from the center, making the shortest radius ring about 3/4 to 1". Anticipated diameter loss in a cherry bowl at 10% EMC , 12-15" in diameter and this ring interval/orientation seems to range from 1/4 to 3/8 of an inch exclusive of rim drop. These fit in nicely, with the worst and largest at nearly 3/8.

Liquid solvent dehydration processes, as I have referenced, are performed by dilution, the same way at least Arch can remember dehydrating samples in Histology lab. The dilute solution is removed and freshened after each soak in successive operations until the desired concentration is obtained. The dehydrated material must then be dried, of course! The magic of alcohol seems to be that it, as the bush on Sinai, burns yet is not consumed. Chemical reactions deplete the reagent(s), replacement dilutes the solvent, which is why it is removed and replaced with fresh to get to the desired concentration. See any of that in the alcohol process? Must be obeying some law other than the known laws of chemistry to work.

"But - but - but, doesn't the alcohol, with its higher vapor pressure (lower boiling point) evaporate faster than water?" Sure, but it doesn't dry the piece any faster unless you've done the dilutions. You can't have it both ways and say that the alcohol speeds the evaporation of water in a short-soak piece. If you distill alcohol from aqueous solution to get to your 95% azeotrope by using Raoult's law, you can't simply repeal it for the evaporation stage to make your theory work.

Which it doesn't. Keep an eye on the relative humidity. You can do as I and leave it open for the air to dilute the water, or protect the wood from too great a surface/interior gradient by bagging, wrapping, coating, or containing. They're all doing the same thing. Which is why they all work, and have since records have been kept and before. It's also why the alcohol "works" - because the water molecules are continually washed away by the surrounding air. It's the dilution you didn't do.

On the subject of weight. Was roughing a piece from near the end of a year-old maple log and noticed how light it felt compared to one I had roughed 40 inches into the same log two days prior, of similar thickness and shape. Piece from just inside the end checks weighed 2155 grams, while the other, which was just barely losing the shadow of unbound surface moisture tilted the scale by weighing more than 3 kilos. The real fun was in the difference between the wet and dry ends of the piece I turned. If I had whipped the speed up on the lathe, that sucker would have wobbled and flown. More than one way to get a piece out of balance.

Fred,

I have noted this in every bowl I've dried using the alcohol method. I believe it is due to much of the alcohol evaporating. I chart the drying progress of each bowl done this way. In addition, I weigh the bowl before immersing it in alcohol.

Try weighing the bowls every day at roughly the same time. I usually consider the bowl dry enough when I get the same reading on three consecutive days. (Using a postal scale that measures to 0.1 ounce.)

Please keep us posted on the progress.

Next time, correct her with "Compared to whom?" ;)

And, Fred, the effort and sharing is appreciated.

When dealing with George's data you might try the parallel experiment that Arch has just documented :).

TomNie

I'm