Drying your green turnings..

[Kenny Regenthal]

Just curious of how you guys dry your green turnings? I like to place mine In a plastic bag with some shavings. I then turn the bag a few times till no water is on them. I was looking for a better way or another that doesn't produce the mold.. any ideas?

 

[hockenbery]

I have found that plastic bags and shavings promote mold.

I put rough turned bowls with wall thickness about 10% of rim diameter in an open grocery bag and put another grocery bag over the opening.
I usually rinse the bowl with water before going into the bag.
I keep the bags away from a fan which will speed drying.
I then swap the bags for a dry pair for about 5 days and let the damp pair dry for use the next day.
Once the bags are not damp I put the bagged bowl on a self standing on its side.
In 4 months I take the bowl,out of the bag and store them upside down on a shelf.
In 6-8 months the bowl will test 10% or less moisture and it's ready to re turn.

Hollow forms and larger natural edge bowls with walls about 3/16" I rinse with water and put in a cardboard box with top closed on day 1,
Top 1/2 open on day 2, top open on day 3, on the shelf on day 4.
This is usually not necessary but the box like the paper bags creates a humidity chamber that slows the drying so one part of the form does not dry faster and move too much.

I use plastic bags to keep a prepared,blank wet if I cannot turn it for a day or so.
Al

 

[hockenbery]

Below are slides I use in a demonstration - working with green wood.

http://aaw.hockenbery.net/WORKING WITH green wood-HOcompressed.pdf

Success in drying goes way up with nice curves, even walls and controlled drying.

Al

 

[Glen Blanchard]

I'm anything but an expert but I would think plastic is one of the last things you want to use. The objective is to slow drying so whatever you put the rough turned objects in should be able to breathe.

I wrap my rough-outs in a couple layers of newspaper taped up with a few lengths of masking tape. Weighed at regular intervals until the weight stabilizes.

Kenny - is that Lewisville, Texas?

 

[robo hippy]

You use different techniques depending in part if you are turning green to final thickness, or if you are twice turning your bowls: rough turn, dry, return. I use the green turn method. Turn down to 1/4 to 3/8 inch thick, round over bowl rims, stretch plastic stretch film around the rim, 1 inch or so over the rim and the rest around the edge/outside of the bowl. Start out on the floor, out of wind, sun, or any heat. Up on a wire rack after a few days, dry in 7 to 14 days. One other method used by Christian Burshard on his madrone is to put the piece in a paper bag and then put that inside a plastic bag. Change out the paper bag every day. This avoids the mold problem. Paper bags can be reused after they dry out again. If you are using dry shavings, this can work as well, and probably change out the shavings after a day or three. With some light colored woods like maple, which have sugar in them, you can get mold under the plastic film. Most of the time, maple is easy to dry without cracking, and the stretch film isn't necessary. It does protect the rim which is generally the most fragile part.

The twice turned bowls are similar, but much slower to dry. Every thing from totally sealing them, to sealing just the end grain, to putting them in dry shavings (wet shavings can add bad mold and color to the wood which doesn't come out). Rounding over the rims is important here too. Drying them out of the sun, wind, and heat is good as well. Mike Mahoney likes to put them in his wine cellar. Perfect humidity and temperature. Of course, each piece and species of wood dries and warps differently. Boiling and steaming are other methods for stabilizing wood that is 'difficult', but it does kind of muddle the colors a bit.

robo hippy

 

[Zach LaPerriere]

Great advice. Experimentation and experience are the best teachers.

That said, I've only been turning seriously for just over a year. I have a dedicated shack for drying rough turned bowls. It's insulated, with a wood stove, and dehumidifier. It could just as well be a dedicated room. I usually rough a large pile of bowls, and then dry the lot, slowly taking the humidity down.

I dry bowls at low temperatures, usually 35-50° F except toward the end of the drying cycle when I can usually get away with bumping up the temperature, and thus the drying speed. I find that I can keep the air much drier and have less checks at the low temps. It's also great for spalted blanks or woods prone to mold, because not much grows at the lower temperatures.
Different species dry at very different speeds. And figured wood, especially burls, generally need to dry much slower in my experience.

I use most of the drying methods: cardboard boxes, paper bags—sometimes blanks in bags in bowls. The plastic wrap that Robohippy mentioned is perfect for bigger blanks that are slow to dry and beginning to develop cracks. The woods I turn will rarely crack on the interior. Sometimes I slap some oil on a blank if I want it to dry a bit slower than the rest, say the blank has a knot in it for example, or other grain that I can see will have troubles drying faster.

I also put blanks that I guess will take longer closer to the floor where it's colder.

I check a representative number of blanks fairly often, checking moisture content, looking for any cracks—essentially looking for feedback to see if I'm drying things too fast, or if I can kick things up a bit by opening boxes/bags, raising the temp, etc.

When I find mold, I spray 10% bleach solution and that knocks it back for a while. You can also spray 90%+ rubbing alcohol (special stuff from the drug store, not the watered down grocery store variety) on, but I haven't found the need to.

Finally, when things are close, blanks go out into the open on metal shelves with about 40% relative humidity (RH) if at lower temps, or up to 50% at higher temps. When the moisture content of blanks hasn't gone down for a while, it's time to finish turn.

 

[Kenny Regenthal]

Kenny - is that Lewisville, Texas?

No sir. Lewisville NC. Just west of Winston-salem.

Wow a lot of good tips and advice. Gonna get some paper bags today..I've used the plastic bag method a lot. I don't like dealing with the mold..but the paper bag method and the wrapping the edge method will be used.

 

[Dave Fritz]

I find different woods require different treatment to dry. Some of you that provided the excellent answers above change your method based on the wood or do you use the same method for all blanks?

 

[hockenbery]

I find different woods require different treatment to dry. Some of you that provided the excellent answers above change your method based on the wood or do you use the same method for all blanks?

I use the paper bags or boxes for all woods.
I live in a humid area so I don't have the same issues someone has in a dry climate where human life itself is difficult.

Al

 

[Dave Fritz]

Do you have some that's more prone to cracking? I find burr and white oak to be a real challenge.

 

[hockenbery]

Do you have some that's more prone to cracking? I find burr and white oak to be a real challenge.

I do mostly hollow forms and NE bowls with curves and no hard angles I don't have any concerns with the woods I use.

I think more in terms of easy woods. Soft maples, camphor, poplar.... Are difficult to get to crack.

To get a piece that would crack for the slides I had to use laurel oak and leave it out.
My first attempt was maple vertical walls, flat bottom, a fat 1/2" thick and it would not crack for me.

For drying large bowls the oaks need a bit more attention to the curves, even wall thickness and balanced grain.
I turn the bottom a bit thinner so I that the bottom thickness including the tenon Is just a bit thicker than the side wall thickness at the rim.
The bottom doesn't warp much so there is plenty of wood for returning.

A sloppy 10" bowl will usually dry without cracks. A sloppy 14" bowl is probably going to crack.

 

[odie]

The idea behind seasoning roughed bowls, is to release moisture very slowly, and steadily. As indicated in this thread, there is more than one way to do it. I take a reading with a moisture meter, and roughed bowls under 14% do not require any method of slowing down the rate of moisture release, while those over 14%, require sealing the wood with a wax emulsion.

https://www.woodturnerscatalog.com/p/45/4032/Artisan-Woodsealer?term=sealer to stablize punky wood

The wax emulsion is brushed on the entire surface area of a roughed bowl. The wax emulsion isn't a sealer, but allows the moisture to release. The coated bowls are then weighed monthly until the weights stabilize. When that happens, the roughed bowl is considered "seasoned", and ready for final turning. Not all woods dry at the same pace, and generally, once a roughed bowl shows the same weight (+/- 5 grams), over a period of 3-4 months, it's ready for final turning. I always use 4 months as the indicator during winter, and 3 months during summer. Some roughed bowls will be ready in as little as 3 months, while others will take over a year to season.

The 10% rule is a good one, but some bowls can have thicker/thinner walls depending on species and atmospheric/temperature conditions in the climate where they are dried, and the location within your shop. Your plans for a final shape could effect this decision. Bowls are stacked with stickers in-between, so that as much external surface is exposed to the shop atmosphere. The usual recommendation is to dry roughed bowls low down, close to floor level, but mine are high up. I've had excellent results doing it this way, but my climate and shop conditions are different than someone down south.....or otherwise where conditions aren't the same as mine.

ko

 

[Dave Fritz]

The problem is I get so much at one time I can't rough turn it all right away. Also some is for spindle work, handles etc. Sometimes I seal it and if it cracks I make the best of what's left but you can only use so many pen blanks. I suspect treating it all the same with max. protection would be the best. For me that would be sealing a couple of times and putting it in brown paper bags and taping them shut.

 

[hockenbery]

Dave when I get fresh wood I don't cut the blanks until I'm ready to turn them. The blanks are hard to keep unless you freeze them.
Dipping them in paraffin can keep them a month or so. Wrapping them in plastic keeps them for a few days.

If you have the equipment leaving them as logs whole works well. Just cut off 4" of waste and cut blanks.
Logs will last for quite a few months maybe a year if you don't wan the sapwood.

I usually cut blank material into half logs 2-3 feet long. These I can move easily with a hand truck and load them on my trailer.
I coat the ends of these with sealtight and stack them in the shade.
When I have a day to turn I cut 2" or so off the end to get rid of the end checking then cut 2-3 blanks and turn them.

The wood begins to deteriorate in color quite quickly. For example the bright white sapwood in Cherry will be dull grey in a week or so.
It will still be nice for bowls especially if you don't use the sapwood.
I might still turn wood that is 6 months old but that is about the time it moves to the firewood pile.

Al

 

[olaf Vogel]

The wax emulsion is brushed on the entire surface area of a roughed bowl. The wax emulsion isn't a sealer, but allows the moisture to release. The coated bowls are then weighed monthly until the weights stabilize. When that happens, the roughed bowl is considered "seasoned", and ready for final turning. Not all woods dry at the same pace, and generally, once a roughed bowl shows the same weight (+/- 5 grams), over a period of 3-4 months, it's ready for final turning. I always use 4 months as the indicator during winter, and 3 months during summer. Some roughed bowls will be ready in as little as 3 months, while others will take over a year to season.

ko

This is basic method I use, even for large stuff. For smaller vessels, that are more closed, I only coat the outside, leave the inside as is. So it bowl dries from the inside out. For larger, and more open bowls, I coat both sides.

All large pieces go in the wine cellar, for controlled temperature and moisture. Basements in older homes generally work well too (not fully finished ones.)
After the cellar, they sit around the living room for a week or two to adjust to the moisture level.

Weigh the piece right away. Makes notes on a small slip of paper (weight, date, any other info you want) and toss it inside.
Come back periodically and reweigh. I use a postal scale for small stuff and an old people scale for big ones.

When it stops getting lighter, you're done!
The time varies, by a lot of factors, and can easily take months. But for me its been the most reliable method.

I just rough turn a lot of pieces and they sit around.

Ideally I try to dry as slow as possible.
A few exceptions:

- if you finish turn right away, a thin piece will dry quickly and shrink across the grain. So the shape will distort. Sometimes thats a nice effect and can be part of the design. In that case you don't want the pith in there.
- microwave drying. I've only done this 3 times, but it worked well all 3 times. Obviously its gotta be small enough to fit in your oven. But you can have a piece dried out in a few hours. The heating breaks down the bonds between the fibers and reduces cracking while drying.

There was a PHD level study done on this and its available for download, although I've forgotten where.
It very scientifically analyzes what happens during the process and how this can be used, wide scale, in industry for drying wood quickly.
Good reading, if a little dry... <pun intended>

 

[Douglas Ladendorf]

...an old people scale...

I had no idea there was a scale made specifically for old people!

 

[Kenny Regenthal]

Another idea that hit me.. I cut some maple logs, basically cut them in half right along the pith. I placed them in a lidded metal trash can. I left it partially open. It seems to be working good. They can dry some, but not too fast. So I figured it was a good step before turning.

Also I have some plain Hackberry, I placed them in a 5 gallon bucket of water. The main reason is I wanted to increase some character... it has caused a little discoloration. But nothing yet. I've even added my wife's old coffee grinds.. just as an experiment

 

[Bill Boehme]

I had no idea there was a scale made specifically for old people!

I have one ... if I could just remember where I put it.

 

[robo hippy]

Kenny, if you are looking to spalt your wood, look into these people. Just water won't do it, and probably not the coffee either. Place it with one end in the dirt, which has lots of fungus in it and you will have more luck.

http://www.northernspalting.com/about-me/

robo hippy

 

[KellyDunn]

As a production turner in a very wet climate I coat the outside of my roughed bowls with sealtite. I do use a moisture meter like Odie does. And I will agree with him that a reading under 14% needs no waxing. but its so wet here that air drying is a joke for me. so I have a cheap kiln made from an old fridge powered by a light bulb. With a few 1/2 in holes drilled in the top and bottom for a convection air current. If I finish turn a bowl on the shelf at ambient 14 to 16% moisture it will go oval and S shaped. NOT what I want. So into the kiln. Almost all pieces have been through the kiln once then put on a shelf. It only takes a couple days for one of those to drop back under 10%. I then leave them in the kiln during the finishing process. Its so wet my finish wont dry for a long time without the kiln helping. I have four of those kilns. Three are working right now. One with a 40 watt bulb full of wet roughed bowls. Two for finishing. Main one with a 40 watt bulb and one with the 100 watt but uses 23. Takes longer but its for pieces already dry that I have in case I want to finish turn THAT particular piece today but with no time horizon. Pieces with 14% or less I tend to coat the outside endgrain just in case and pop it into either the 40 or 23 watt kiln. I have many hundreds of roughed bowls, work by myself and am not in a hurry. Want to know? A moisture meter is worth the price of admission. I have a mini Ligno. I have heard of folks getting a good price on them off Ebay. But depending on the woods you use and your climate you need to come up with what will work for you. Oh, and cracks dont bother me one bit. I do lots of the Hawaiian butterfly patches. A bowl that goes so oval it cant be returned is another learning curve of leaving enough wood.

 

[Gerald Lawrence]

Drying bowls is dynamic and will always vary by the type of turner (pro or hobby) and the geographic location. Another variable not mentioned so far is the shop environment. My shop is conditioned by a heat pump and is well insulated. This may be why my method works for me. Moisture meters only tell moisture up to 1/4 inch deep and not for the whole blank.
My method is to rough turn and after weighing ,put in paper bag with fresh chips (dry chips will cause to dry to fast). Weight is noted with the date on paper. For about a week to 10 days I weigh daily and usually drop enough weight to remove chips. Then I weigh 3-4 times a week and when drying slows considerably take it out of the bag and continue weighing. When the bowl stops losing weight it is dry enough to return. Please note that blanks expose to atmosphere can gain weight when humidity rises.
Yes I do get some cracks, but for me I can glue and go . This is as I stated my method for the rough turning, for logs they last a lot longer than the 6 months Al stated. I have Cherry that was cut in May and will go for another 4-7 months and still be cherry red. I do coat the ends of logs and 1/2 logs with parafin or candle wax (from electric skillet).

 

[Kenny Regenthal]

Kenny, if you are looking to spalt your wood, look into these people. Just water won't do it, and probably not the coffee either. Place it with one end in the dirt, which has lots of fungus in it and you will have more luck.

http://www.northernspalting.com/about-me/

robo hippy

Ok thank you for the site. Didn't think of dirt...I just wanted to try a few things. Never know till you try it. PLUS I didn't have any money in the wood. So no loss there.

A.lot of great info here. I see a moisture meter is in my future.

 

[Gretch Flo]

Kenny, if you are looking to spalt your wood, look into these people. Just water won't do it, and probably not the coffee either. Place it with one end in the dirt, which has lots of fungus in it and you will have more luck.

http://www.northernspalting.com/about-me/

robo hippy

Reed/(aka Robo) and Kenny. I get the 20 cords in the 8 ft log lengths stacked in piles off the the font side of house. It spalts in the next year or 3 very nicely doing nothing. This past 2 years i was having a hard time saving some of it for firewood!!!! Gretch

 

[olaf Vogel]

I get the 20 cords in the 8 ft log lengths stacked in piles off the the font side of house. It spalts in the next year or 3 very nicely doing nothing. This past 2 years i was having a hard time saving some of it for firewood!!!! Gretch

Now I'm jealous!

 

[robo hippy]

If you ever get a chance to see Sari Robertson, or Robinson, can't remember, she is well worth it. One of the most interesting demonstrations I have ever seen. One primary reason for me was that pretty much everything I knew about spalting was wrong. One of the more interesting points was that all the home brew concoctions for inducing spalting are pretty much worthless because the fungi that do the spalting will eat the 'easy' food first before starting in on the wood. Most spalting is done in about 3 months max, then the wood gets too far gone.

I prefer warped bowls. "They are soooooo Organic!" is the most frequent comment. Cracked bowls go into a box and I take the rejects to a show and sell for at most $5. Main reason is that it takes so much extra time to repair them, it just isn't worth the extra effort for me.

robo hippy

 

[Jay Mullins]

Drying your green turnings

​

No sir. Lewisville NC. Just west of Winston-salem.

Wow a lot of good tips and advice. Gonna get some paper bags today..I've used the plastic bag method a lot. I don't like dealing with the mold..but the paper bag method and the wrapping the edge method will be used.

Kenny,

I've used the stretch plastic quite a bit and had success with it most of the time. I've also used the plastic bags also with success. The narrow roll of stretch plastic found in the office supply stores is 5" wide by 1000' long. It's $9.97 a roll at Staples and $6.97 at Walmart.

Jay Mullins

 

[Kenny Regenthal]

Ok I remember you saying that now. I'll go and get a roll this week. I'll have to try it out and see how it works... Say also what was the website for the replacement carbide tips?

Kenny

 

[Jay Mullins]

drying your green turnings

Kenny,

I posted the information you requested to your e-mail. Also a request from me.

Be Well

 

[Ted Moore]

I turn a bowl to roughly 10% thickness to outside diameter, then coat the entire bowl in anchorseal2.
Sticker it up and stack in my basement that averages 65* F and 40% RH.
Couple months later I'll check it with a pinless moisture meter and return.
I did the boxes, the, bags, shavings, etc. And found they prolong the drying too much for me.
This is what works for me in upstate SC.

 

[Kenny Regenthal]

I gotcha. Pretty good idea. Figure how close you are to me. Our climates should be close to the same. So I could possibly do the same... What brand moisture meter do you have? I like the idea of a pin less one..

 

[Bill Boehme]

I gotcha. Pretty good idea. Figure how close you are to me. Our climates should be close to the same. So I could possibly do the same... What brand moisture meter do you have? I like the idea of a pin less one..

I prefer using a digital scale that can read weight in grams. Its a lot cheaper than a moisture meter and gives a more definite indication of when the bowl has reached EMC. Just periodically check the weight and write it on a Post-It that you place in the bowl. Generally, the free water evaporates in the first four weeks. Warping doesn't begin until the bound water starts evaporating which will take an additional 12 to 24 weeks to reach EMC depending on the size and thickness of the rough turning. It's not essential that you wait until the roughout reaches EMC ... when the weight loss slows to a few grams between measurements, that's close enough.

 

[Gerald Lawrence]

I prefer using a digital scale that can read weight in grams. Its a lot cheaper than a moisture meter and gives a more definite indication of when the bowl has reached EMC. Just periodically check the weight and write it on a Post-It that you place in the bowl. Generally, the free water evaporates in the first four weeks. Warping doesn't begin until the bound water starts evaporating which will take an additional 12 to 24 weeks to reach EMC depending on the size and thickness of the rough turning. It's not essential that you wait until the roughout reaches EMC ... when the weight loss slows to a few grams between measurements, that's close enough.

Bill has hit it on the head. I use sheets (I may only have 6-8 drying at once) and record weight 3 times a week. I will reintegrate that moisture meters do not give complete internal moisture levels , only about 1/4 inch into the piece.

 

[Gretch Flo]

Bill has hit it on the head. I use sheets (I may only have 6-8 drying at once) and record weight 3 times a week. I will reintegrate that moisture meters do not give complete internal moisture levels , only about 1/4 inch into the piece.

Gerald I have a wagner pinless moisture meter and love it as I have mentioned before on the forum. . Not sure how far it reaches. but have a half inch (x12"x4") drying bowl that reads 8% tonight and if I put my finger under it it raises it to 13%. I have a thin 3/16 " bowl reading 6%, and with my finger under the wood it goes to 13%/ My finger alone goes above the max at 22%. So it's not accurate perhaps, but there is some reading in a thicker bowl and not just 1/4". . It is all relative anyway as I wait for the % to stabilize just like some wait for the Grams to stabilize. Seems when I looked on line a while back wagner had different depths depending on the model, but my info accompanying the wagner didn't state a depth. Seems when I got it ?8-10 years ago it was around $130, and last I looked it was approaching $200. Yes it is expensive. Was a gift. Would I spend this kind of $ today??? I doubt it unless I needed a tax deduction!!! Gretch

 

[robo hippy]

Err, what's a moisture meter???? Even if I did the twice turned bowls, with the quantity I do, even now after quitting the craft shows, I wouldn't use one. More than anything, I would keep adding to stock on one end and removing from the other. It would take too much time to weigh them all, and use the moisture meter. If you pay attention, you can develop a feel for how wet or dry the wood is by touch and weight. Maybe not a skill for every one, but it is like a guessing game I play with the out doors thermometer, what is the temp in the shade right now. I can get 'close enough'. With once turned bowls, not necessary at all.

robo hippy

 

[dbonertz]

Weighing works but I turn and dry quantity so it seems a waste of time if drying more than 10 blanks at once. I kiln dry around 160 blanks in my kiln so a moisture meter is essential for me. They are more accurate than what I have read from folks posting. As Gerald said they don't read the interior of the blank but I can tell you they read really close on the interior as to what is read from the depth of the pins on the exterior. I dry the blanks down to around 8%. I have cut several blanks in half to check the interior wall moisture content and they have all read within 1% to 2% different than the exterior pin depth. Darn close enough for me and what we do, so they are pretty accurate.

Just in case anyone is wondering I don't check every blank coming out of my kiln. I dry several species in any given kiln load so I like to make sure each species has dried enough. I will generally check one blank of each species from that kiln load.

 

[Bill Boehme]

I did a bunch of weighing in the past in order to generate some data to see how fast wood dries is this climate. It didn't take long to see that drying is very predictable and it is not necessary to continually do this unless you like to do science experiments more than you like to turn wood. Each species of wood is slightly different so it is important to recognize that and consider making some measurements if you are unsure about some species that you haven't turned before. Dale is right that weighing and using a moisture meter take time. He does production turning so time is a lot more important to him than it might be to a weekend warrior.

Sometimes, if I have a special piece of wood I might decide to take at least an occasional measurement to get an idea of the trend in order to estimate when the piece will be dry enough to finish.

The reason that I said that weighing was more accurate in determining when EMC has been reached is that knowing the precise moisture value, by itself, doesn't tell you if that value is EMC unless you have other information to complete the picture. Of course, kiln drying is the exception because the moisture content is taken down well below ambient EMC. Weighing, on the other hand, doesn't tell you what the percent moisture content is ... it only tells you when the drying has stabilized at EMC. For my purposes, knowing an actual number for moisture content percentage isn't the answer that I am seeking for my question, "is the wood dry"? When the piece stops losing weight, Ive the answer that I want. If I look at the weight loss trend, I am able to extrapolate ahead in time to make a good guess as to when the piece will be dry enough to finish.

Gretch mentioned taking MC readings on pieces that are 1/4" and 3/16" thick. The readings won't be as accurate as checking the MC on a thicker piece, but around here it would be sort of pointless anyway because something that thin would be dry before it came off the lathe.

 

[Donald Bear]

Plastic film

Mr. Robo Hippy,
Are you saying to cover the entire bowl in film? Just want to make sure I understand correctly.