How do I start drying green wood bowls?
There are many approaches for drying green wood bowls once they have been turned or roughed out, including using paper bags, a microwave, kiln, denatured alcohol, even desiccant drying beads, or just simply waiting.
Inside Drying Green Wood Bowls
In a dream world, we could find a freshly cut tree, process the green wood into bowl blanks, turn a bowl, then set that bowl on the shelf and it will always look like it just came off the lathe.
Unfortunately, that is not the nature of wood.
Fresh cut or green wood contains moisture. For that matter, even logs cuts years ago usually hold moisture to some degree.
This moisture inside wood can remain trapped or escape over time, based on many different factors. If not managed, uneven moisture movement causes stresses in the green wood and will likely change the overall shape of a turned bowl, or cause structural failure in the form of cracks, checks, and splits.
As we have covered in Turning Green Wood Bowls, the term “drying green wood,” is really not a thing. A more accurate term is “equalizing wood,” but since “drying” is what most people think and say, we’ll use the term “drying” to keep this simple.
Ultimately, we really want to control our green wood bowl turning to fit our specific needs. Once-turned and twice-turned bowls have different characteristics.
The quicker and more abrupt the drying process happens for once-turned bowls, the more chances there are for cracks and unpleasant results.
Waiting for full twice-turned bowls to dry is boring and forces us to wait to have the beautiful final turned bowl we are imagining.
With the following methods, we can manage the even moisture equilibrium within our drying green wood bowls.
If you’d like to learn all about the twice-turning process, be sure to read this article.
Green Wood Off the Lathe
It is possible to take a freshly turned green wood bowl from the lathe and place it on your shelf and it will dry fine without problems. However, this is the exception and will be highly dependent on several factors.
Drying Green Wood Bowls, Dynamic Contributing Factors Include
- tree species
- time since cut
- relative humidity
- temperature
- air flow
- light sources
- heat sources
- bowl wall thickness
- bowl shape
Enemies
To more closely control and ease the drying process we need to be aware of our enemies. The two biggest enemies are unevenness and environment.
If the wood is turned uneven, with thick and thin areas, it is almost impossible to dry these areas smoothly without tension and cracks forming.
Controlling the environment is critical to ease the process of drying green wood bowls. Specifically, humidity, heat, moving air, and light are the elements working against us obtaining a crack-free final bowl.
We must protect our new green wood bowl turning from these mean evil forces. The best way to accomplish this is to turn an even bowl shape and protect that turned piece afterward from the natural forces working in opposition.
Drying Green Wood Bowls Slow or Quick
When drying green wood bowls, we have two different routes to take.
The first route is to turn the wood once and ease the drying process, so the wood does not change too much or too quickly. We want to avoid causing cracks and splits.
With once-turned bowls, because the bowl walls are usually thin and will quickly leach out moisture and potentially dry uneven, we are trying to slow and even out the drying time.
The other route to take is to twice-turn the green wood, which we’ll discuss more in a moment. The first turning is deliberately oversized and designed to take the stress of change during drying.
While we still want a smooth process to a “dry” bowl with the twice-turned method, we are also usually trying to speed this method because the wood is thicker and will take much longer to dry naturally.
Drying Green Wood Bowls Once-Turned
A once-turned bowl is a piece of green wood turned into a bowl at final shape and wall thickness. After the turning, the initial form of the bowl is finished at that point. Now, nature takes over.
With a once-turned bowl, depending on wall thickness, the piece will dry, move and transform into its finished form as is dries. If the bowl is turned thin, it may shift, warp, and buckle much more noticeably. This can be a desirable or not-so-desirable effect.
Either way, a thin-walled bowl will dry quickly, usually within a few days, and reach its finished look in a short time. Very thin walled bowls can dry in a matter of hours.
It is not recommended to seal the end grain of once turned bowls. Since it won’t be turned a second time, removing the sealer can be difficult or nearly impossible without damaging the finished bowl. Sealing end grain is more important with twice-turned bowls, which we will cover in a moment.
Instead of sealing the end grain of once turned bowls, we need to slow the drying process by controlling the bowl’s environment. Using the paper bag method (below) and/or spraying the end grain periodically with water to keep the wood evenly moist are two such approaches.
Once-turned bowls tend to have a very organic, natural look to them with offset curves and rims that may rise and lower from side to side. This may or may not be the look you’d like to achieve for the final bowl.
Drying Twice-Turned Green Bowls
As the name implies, twice-turned green bowls will be turned twice. Why you might ask? To obtain a more accurate round shape for the final bowl.
The first turning of a twice-turned bowl will be allowed to thoroughly dry. In the process of drying the bowl will usually pull outward at the pith, contract on the sides and essentially stretch.
With the walls of a twice-turned bowl made thick, 10 percent of the overall diameter, there is wiggle room to “correct” this movement. I will also carefully make my tenon a bit larger so that it will still be held properly by the four jaw chuck when it’s trued up after drying.
Basically, we let the first turned bowl do all the warping, moving, and shaping, then, once dry, turn it a second time to the final shape and final wall thickness. Because the wood, after the first turning and some time, is dry or equalized, the amount of movement after the second turning is minimal.
All of the methods below will work for twice-turned bowls. Because of the thick walls of the first turned bowl, it’s a great idea to seal the bowl’s end grain with Anchorseal before starting the drying process.
Sealing the end grain of the bowl slows the amount of moisture leaking from the open end grain. The goal is to have a more even moisture loss from both the side and end grain.
Evenness is the key.
Final twice-turned bowls usually look perfectly round with clean circular rims and fresh, crisp lines.
DRY GREEN WOOD BOWLS – Six Methods
Method One – Hope and A Prayer
Take a piece of green wood and turn it into a finish shaped bowl or a rough-turned bowl. See, Turning Green Wood Bowls – The Process, for more about twice, or rough-turning. Set the turned bowl aside.
Again, remember every wood species is different, and all the external forces acting on that bowl are always present. Some woods are super cooperative, and you will have no trouble, while others species seem to crack when you look at them wrong.
The finished turned bowl needs to be reasonably uniform in thickness throughout. If, for example, the walls near the rim are thin and the base is thick, more moisture will remain in the base after the thin walls have dried and this can cause uneven stress to crack the bowl.
For a final turned bowl, think how the environment will affect the equalizing wood. A low, cool, dark, sealed cupboard will be a much better storage location than a countertop, in the sunlight, near a breezy open door or heat source.
Set the final turned bowl aside and hope for the best. In a few days or weeks, the results will be revealed. I’ve done this many times with success and several times with failure.
I have turned green wood and done nothing else to it afterward, with decent results. The bowls that come to mind were turned from two-year-old cut hickory, so, while green, the wood was much drier than when first cut with the chainsaw.
By the way, there are many aspects to making your chainsaw blade sharp at all times. Check out this article for all the tips to perfectly sharpen your chainsaw.
Another contributing factor is the nature of the hickory species, which is a solid and stout structure. Also, the hickory bowls were turned with walls about 1/4” to 3/8” thick, not thin and not too thick. Even though they dried fine without cracks, there was some movement, noticeably waves along the rims.
Method Two – Paper Bags To The Rescue
Yes, brown grocery bags work well to allow the wet green wood bowl to release moisture slowly and evenly over time. Because the paper bag breathes, it will gradually release excess moisture and progressively dry, exactly what we need.
The paper bag with wet fresh shavings makes a controlled micro-climate for our wet green wood bowl.
Simply collect some wet shaving from the shop floor, preferably the ones from the same bowl, and line a paper grocery bag. Place the bowl or roughed blank inside, cover the bowl with more wet shavings and fold over the bag top and loosely tape the bag shut. Put this is a cool dark area that has little air movement. A cabinet or cupboard works well.
This is an important note. Don’t place a green wood bowl in a plastic sealed bag. In moist locations with humidity, plastic bags will hold in moisture and most likely cause mold, bacteria and rot to form, not things we want for our beautiful bowls.
The exception to the plastic bag rule is severely dry, arid locations, such as the desert. In these locations, plastic bags are used to try to retain moisture in the green wood bowl longer and slow the evaporation process.
Everything is relevant!
For the rest of us, that live in areas where there is a fair amount of relative humidity in the air on a regular basis, paper bags breathe and help regulate the passage of moisture very effectively.
The moist, fresh shavings will slow drying but because they are surrounding the bowl, they aid in regulating or buffering the amount and speed at which the moisture leaves the green wood bowl.
After a week or so, it is a good idea to move the green wood bowl turning to a new fresh paper bag. You can check the bowl’s dryness when you move it as well. The fresh paper will prevent excess moisture build-up and reduce bacteria or mold formation.
Approximately every week or so, (days if the piece is thin) check the piece and see if it is drying evenly without cracks. Remove the shavings if they are dried up. Return the turned bowl to a new fresh grocery bag without shavings, close the top, and return it to a quiet area free from too much air movement.
Check the moisture content of the wood as we will discuss below and once it equalizes the process is complete.
Method Three: Kiln Drying
If you have access to a dryer or kiln, this can be a great way to dry twice-turned thicker green wood bowls quickly. However, again, I suggest experimenting with this process too. Every species will act differently. One bowl might dry beautifully in a dryer, while another may disintegrate.
A homemade kiln can be made out of an old refrigerator, an insulated cabinet, or a box made from foam house insulation.
Just cut a vent hole in the old refrigerator base and one in the top and place a light fixture with an incandescent light bulb inside. The heat from the light will slowly dry the wood bowl blanks.
A systematic approach for advancing lightbulb sizes can be used to increase the temperature slowly and gradually over the course of several weeks by using progressively larger bulbs.
Start with a 40w bulb, then a 60w and finally a 100w bulb. Check the moisture content of the wood with a moisture meter or weigh the pieces to determine when they have equalized.
Be careful, however. Keep in mind that quick, sudden, unstable changes in the wood structure are what will result in the most problems. So easy does it and the more even everything is along the way, the better.
This method is best suited for drying rough-turned bowls that will later be twice turned to their final shape and form. A kiln or drier can take the drying time for thicker twice-turned bowls from months or even years to only a few weeks.
Method Four: Microwave Green Bowl Drying
Microwave drying a wood bowl blank can be done with short times in the microwave at full power, around 30 seconds, followed by cooling time, around 30 minutes. Repeat the process weighing the wood bowl after each session until the weight of the bowl stabilizes.
If your bowl or roughed blank will fit into the microwave and if your spouse approves or is unaware you may want to try this technique. A garage sale microwave, just for drying green wood in your shop might be a better way to avoid domestic disputes. Just saying. 😉
Microwave the turned bowl on high for a very short period, 20-30 seconds. After each session, remove the piece and set it out to cool for at least a half hour.
I place the blank on the counter in the kitchen and prop it up on a side so that most of the bowl has good air exposure. The heated bowl will lose moisture through evaporation, so it’s essential that all surfaces of the bowl breathe.
After at least a half hour of cooling, I pop it back in the microwave for another 20-30 second dose. Repeat this process eight to ten times until the moisture content equalizes and the bowl is dry.
Don’t be mistaken, this isn’t as fast as a microwaved meal, but still much quicker than nature ever imagined.
If you’re microwave drying a thick rough turned bowl, it may take a few more trips to the microwave until the wood equalizes, then you’re ready to do the final turning.
Microwave drying green wood bowls aren’t as fast as making a bag of popcorn, but it sure beats waiting years.
Method Five: Drying Green Wood Bowls in Denatured Alcohol
Soaking rough turned or finished bowls in denatured alcohol creates a chemical process that bonds alcohol to the internal water in the bowl’s wood cells. During the drying process, this mixture evaporates from the wood very quickly.
This process requires that the bowl is completely submerged in denatured alcohol. A resealable plastic container just big enough to hold the bowl is ideal.
High quality denatured alcohol can be purchased in gallon containers, and enough is needed to completely cover the whole bowl.
Soak the bowl for approximately 24 hours before removing the bowl from the denatured alcohol. It’s not a bad idea to let the excess denatured alcohol drip back into the container so it can be used again later.
After the excess denatured alcohol is no longer dripping from the bowl, place the bowl in a paper grocery bag and press the paper around the bowl snuggly. In my research, I found some people take the time to wrap the bowl in brown craft paper, taping it securely shut with tape, like a wrapped gift.
The time it takes the denatured alcohol and water mixture to escape the wood cells in the bowl will vary but can take from one to three weeks. Like, everything we’ve discussed so far, all the various factors will contribute in different ways to affect the drying time.
Once the wood does not smell like denatured alcohol, the process should be complete. Use the techniques described below to determine dryness or the equilibrium of the moisture content in the wood bowl.
While I have not tried this technique yet, it appears to be a viable green wood drying solution for both finished once-turned bowls and roughed twice-turned bowls.
Method Six: Desiccant Green Wood Bowl Drying
When I first learned of this process, I had to stop and try to figure out how to pronounce the word, “desiccant.” Desiccant defined, is a hygroscopic substance used as a drying agent. Think of the little silica gel packets that come in some product packaging to keep the product dry.
Yes, you can purchase large amounts of desiccant and use it in the process of drying green wood bowls. I have a link in my Green Wood Resource Guide for buying desiccant in volume. No need to try to collect 10,000 little packets from various product packaging.
Here’s the cool thing about desiccant. Desiccant drying beads are color-coded, and they change color when they are saturated with moisture.
And the best part about using desiccant is that it’s reusable. Just spread the moist beads out on a cookie sheet and bake them in the oven at 250° until they are dry and ready to use again.
Desiccant needs to be sealed and not exposed to air ever. If the desiccant beads are left exposed to air, they will suck up the humidity in the air until they become saturated again.
To use the desiccant beads to dry a green wood bowl, place a layer of desiccant in a sealable plastic bag and then place the green bowl inside the bag. Completely cover the bowl with desiccant until the wood bowl is not visible, then tightly seal the plastic bag.
Depending on the size, thickness, and shape of the green wood bowl, the desiccant can dry the wood in as little as 24 hours.
Check the bowl for dryness and see if the beads have changed color to indicated moisture saturation. If the beads are wet and the bowl is not entirely equalized, bake the beads until dry and do it again.
Managing Twice-Turned Green Wood Bowls
If the particular wood species you are using is prone to cracking, it is a good idea to seal the end grain immediately after turning the twice-turned rough green wood bowl. Anchorseal is a breathable sealer that allows moisture to slowly escape and it aids in preventing cracking end grain.
For the bowls I twice-turn, I seal the end grain liberally inside and out on the roughed bowls. As the wood drys, it will lose moisture more evenly from the end and unsealed side grain.
Without the Anchorseal end-grain sealing application, the green wood pours the moisture primarily out the end grain with very little escaping from the side grain. This unevenness, like unevenly turned bowl walls, causes unbalanced stress and cracking of the turned bowl.
Think of the cells and grain of the wood like drinking straws. The end grain is the open end of the straws, and moisture quickly leaves these areas unevenly and causes stress cracks.
Later, when the rough-turned bowl has dried or equalized, it can be turned a second time to the final shape and thickness. At that point, because the green wood has undergone the drying and movement process already, it will stay very close to the final turned appearance with little or no further shapeshifting.
Measuring Green Wood Bowl Dryness
So how do we know when the wood is “dry,” (a.k.a. equalized)? We need to measure and check.
When you’ve worked with a particular wood long enough, you can sense when the wood is dry and stable. However, that can be an elusive and time-consuming sense to acquire.
There are two ways to measure for dryness. A standard wood moisture meter can be used to measure the moisture content in your bowl.
The only problem with this method is it can leave small pinprick holes in the bowl surface. Also, readings taken from different areas of the bowl can reveal very different results.
I’ve found that I don’t always get a confident answer with moisture meters. However, I do use a moisture meter to determine very wet wood compared to more dry wood.
For more precision, I use the following technique to measure green wood equilibrium.
Weighing Dryness
The method I find most useful for measuring the dryness of a green wood bowl turning is weighing the bowl. Yes, weighing the bowl will give you the best results because you actually measure the amount of water in the bowl.
I find weighing in grams is the easiest way to get a precise, and easily comparable weight reading each time. Use a small digital scale, like this one, which has a gram reading and weigh the bowl. On a slip of paper, write the date and the weight in grams.
Come back a few days later and repeat the process.
Here’s the cool simple conclusion to this process. When the weight stabilizes, the bowl’s moisture content has equalized for its environment.
It’s really that simple.
Equilibrium Can Go Both Ways
Believe it or not, I had a twice-turned bowl roughed out and placed in a dryer. I kinda forgot about it until one day I decided to pull it out and turn it for the final finished shape. Everything was fine with the wood, no cracks formed and it turned very well.
With the piece complete, I decided to weigh the bowl to measure how much moisture was still inside. As the days went by and I noted the progress, I was quite surprised. This bowl was not losing weight, but instead GAINING weight.
What had happened?
Well, in the time I forgot the roughed bowl in the dryer, the green wood went past the point of equilibrium, and the wood cells held less moisture than the relative surrounding air humidity.
When the bowl was removed from the dryer and returned to the relatively moist air it began absorbing that moisture and gained weight, just like a dry kitchen sponge soaking up water.
The moisture weight gain was minimal and did not change the bowl shape or structure enough to notice, but it was a great example of how the wood is never truly dry and always evolving.
Experiment
I hope this article gives you new ideas for how to work with green wood. There are many advantages to working with green wood, but most importantly, remember to experiment.
With all the possible variables it’s impossible to know precisely what will work and what will not. Without committing too much time, simply turn a few pieces and try drying them a couple different ways.
Take notes about your drying processes so you can recall what works. Once you’ve discovered a process for a particular species of wood, forge ahead and start creating beautiful green wood turned bowls with your new knowledge!
Drying Green Wood Bowls Conclusion
Green wood is fantastic to turn, low on flying dust, easy on tools, and usually very affordable, as in FREE. Awareness of the changes that take place once the green wood is turned is the key.
It is important to realize a transformation is taking place from a living structure to a more static artistic form. The transition between these states must be acknowledged and respected.
With a bit of experimenting and knowledge about how wet green wood dries, or equalizes to the surrounding ambient conditions, we can more reliably make fantastic green wood bowls.
While it might seem a bit frustrating, while striving for the best looking bowls possible, cracks and mishaps are going to happen. Learn from them. Remember what works and what doesn’t work, then play and have a blast turning and drying green wood bowls over and over.
Here are other green wood articles to consider:
• TWICE TURNING WOOD BOWLS – HOW TO STEP BY STEP
• BANDSAW BASICS FOR WOOD BOWL TURNERS
• GREEN WOOD BOWL BLANK MAKING PROCESS
• BOWL TURNING GRAIN ORIENTATION – WOOD BLANK DIRECTION
Happy Turning,
Kent
70 Responses
Should I use anchorseal (or latex paint) on rough cut bowls that I plan to put in a microwave? I have used the microwave method with some success but oak and maple still seem to crack some using this method. Especially the oak. The maple cracks were small and I was able to turn the cracks out when I finished them, but the I had to turn the oak down so much to get the cracks out that it made a completely different bowl and much smaller than I had planned.
Lang,
Good question.
No, when microwave drying I do not seal the end grain because I want the moisture to escape as soon as possible. If cracks start to form I might take a break and glue them to reduce their spread, but that’s all I’d do.
Happy Turning!
Kent
Good day Kent,
Using a moister meter, what percentages are we looking for before we start turning whether we are turning a 2nd turn or for a one and done?
Bill,
Good question. I usually don’t use a moisture meter because they rarely are accurate with thick timber. We cover this more in the Tree to Bowl course.
All the best to you and Happy Turning!
Kent
Would you recommend (or not) drying your piece before you turn it? That is just after you have cut your log into “blank” pieces and cut into circular pieces to turn. I am considering using an infrared.heater, that is one that turns red hot to heat and dry the wood “blanks” before turning.
Rick,
There’s no need to dry the wood before turning. You can turn dripping wet wood, medium wet wood, somewhat dry wood and very dry wood. All wood moisture types can be turned at any time. Also, attempting to dry the wood with a heater will most likely result in severely cracked wood.
We cover all the details to this topic thoroughly in the Tree to Bowl – Understanding Green Wood course http://www.TurnAWoodBowl.com/green It is truly worth every cent. This is a topic that is rarely covered well and needs to be understood.
All the best to you and Happy Turning!
Kent
I recently turned an emerging bowl from a 7″ walnut log. The log was much wetter than I thought. What method of drying would you recommend based on the half the bowl having a thin wall and the other half being half of the log. I applied some finish and so far so good. The other half log I put in a paper bag with shavings from the first one but being 3.5″ thick would mean 3.5 years before I could turn it.
Thanks for your great articles and videos I have learned a lot.
Cheers Alex
Alex,
Good question. Unfortunately, there are many elements to consider. I recommend checking out my Tree to Bowl online Course. We cover all this info and much more there. http://www.TurnAWoodBowl.com/green
Happy Turning!
Kent
Hi Kent, love your channel and have learned so much over the past 4 years of turning. I read all the comments about the different methods to dry or stabilize green wood bowls. The one method I did not see is using a food dehydrator for this purpose. .I stumbled across this in a you tube video by the Wood Whirler about a year ago. Jumped right in and bought a dehydrator and went for it. I have turned 10 green bowls. Nine of them were finished turned with 2 coats of sanding sealer before placing them in the dehydrator. Ran them at 131 degrees for between 40 and 70 hours
and none of them developed any cracks. I just did a twice turned bowl where I lowered the temp to 100 degrees thinking being thicker slower would be better. I gave a presentation to my club ( Southern Utah Wood Turners ) which sparked a lot of interest. I would love your feedback on this. Thanks Reiner
Reiner,
Thank you for writing and sharing! Sounds fascinating. How big are that food dehydrator and your bowl blanks?
I’m guessing your environment is helping a bit with drying too.
Thanks again and Happy Turning!
Kent
I am attempting to make a dryer box using an old kitchen proofer. I have disconnected the heating element, as this would result in a fast spinning meter, and probably way too high temp. I left the fan connected, and the back of the proofer has a vent where air travels up through a register and is displaced evenly inside the proofer. My plan is to install a 60w light bulb, and install some insulation board on the wall interior. There is a crack at the door seal, which I think is enough for a decent vent path for air flow. I have two questions: 1: should I apply achorseal to the end grain of the bowl(s) after the first turning prior to putting them in the dryer box? 2: Prior to making the second turn on the bowl(s), how do I re-shape the tenon if needed? (jam chuck and tail stock center). By the way, I’m very new and really have learned a lot from your videos.
Hello Shan,
Your dryer sounds great.
And yes you only need temps around 80-100° F to dry the blanks.
Seal the end-grain of the roughed bowls first.
And I have several videos about twice-turning. Here’s one to view https://youtu.be/2qor9wes5zk
All the best to you and Happy Turning!
Kent
Can a person use salt to dry a green turned bowl? You can buy salt at a feed store reasonable . A 50 lb bag. I have not done it yet but have thought a lot about it. Covering a turned bowl like you wood with decadent.
Denny,
I have never tried it, but it sounds possible. I say give it a try. Experiment!
All the best to you and Happy Turning!
Kent
Hi Kent,
I’ve had my lathe for about 5 months & first want to thank you for your on-line content – my go-to source for all things turning. My first bowl projects were from various dry hardwoods & now I’m playing with turning green wood. I cut a lot of firewood every year & look forward to the day I can make some nice bowls from the tree crotches instead of fighting with them on the splitter – a win/win. You mention above that you coat the end grain of rough green wood bowls with Anchorseal (I use Lee Valley’s log sealer – looks like the same stuff). Prior to reading this I rough turned a green wood bowl & coated the whole thing with log sealer. I also coated all cut surfaces on several blanks I made. Is it a mistake to coat side grain too? Now I’m thinking maybe this will slow the drying process unnecessarily.
Brian,
Great question.
In general, the side grain will release moisture much slower and it doesn’t need to be coated. But that said, it depends on the species and conditions. Experiement with a batch and see if there’s a difference with coating side grain or not.
All the best to you and Happy Turning!
Kent
I simply put my once-turned live edge bowls on the shelf in my shop and the vast majority do not crack. I used to seal them but it did not reduce the cracking significantly, it added work, and I simply filled the ones that cracked with turquoise and could raise my asking price for that piece.
Humidity level in my shop is 40-50%.
If I want to dry them faster, I microwave them until they are very hot, but I let them cool in the microwave or put them in a plastic bag until cool. They lose a lot of moisture but don’t crack because they’re in a very high humidity environment. I don’t dry them all the way, but this reduced the total drying time quite a bit.
Ken –
Very helpful. I’ve been woodworking for many years, but I”ve only been into green wood twice turning about a year and a half now. I’m doing all of the things you mention but still have a problem with cracking. I notice you seal just the end grain, i’ve been sealing the whole thing – might that be my problem? Also – the 1/10 rule for wall thickness gives a very thick wall on big bowls – should there be a limit there, say not thicker than 1.25″?
Your content is very helpful, thanks for sharing!
Yes, try sealing just the end grain areas inside and out. Moisture escapes slowly from the side grain, if it too is sealed almost no moisture will escape from the side and then there is uneven moisture loss. That is what causes cracking. By sealing the end grain moisture is lost more evenly throughout the blank.
The 10 percent rule is to assure there is enough material remaining after the piece distorts to turn a “true” round wall. If you limit this there will be issues. For example, a 20″ bowl roughed with only a 1.25″ wall thickness can distort and move more than an inch+, depending on species and moisture. When that roughed dry bowl is returned to the lathe, the send turning could blow right through the sidewalls because they have moved farther inward than the end grain. The 10% rule is the way to go, regardless of the size of the bowl. Happy Turning!
Hi, Kent, Great video on microwave drying. I tried it recently with a small piece of peach that resulted in a 4″ diameter bowl that I left the edge thickness about 15% of the diameter (followed your example of a turned base above the dovetail, which worked well). I put it in the microwave (1200 watts) for 15 seconds and it was rather warm when I took it out. Weighed it, waited an hour, did it again, and it came out with a number of cracks. Further research indicated that cracks result from too much heat, so I’ll turn another one the same size and try 15 seconds with 30-60 minutes between cycles and see how that works.
Two quick questions:
1) Is there a way to tell or guess at how much time should be used for each microwave cycle? Some guys suggest using 50% power; most suggest longer times. Obviously, too little time won’t dry the bowl; too much cracks it. Equally obvious, both the wood and the size of the bowl impact the drying cycle. Perhaps I should start with very short times and work up based on how warm the bowl is at the end of each cycle?
2) Have you ever used a product called Cedarshield, (it apparently used to be called Cedar Treat or Turner’s Choice)? Supposedly, this treatment reacts with the moisture in the wood and turns it into a stable gel and prevents cracks. It is marketed by a company called Cedarcide, designed for any type of wood and allows the use of just about any finish once it dries in about 72 hours. It is reportedly used by a commercial company in Hawaii who struggled for years with turned bowls that would crack when moved to a much less humid location in the mainland.
3) How do I join? I was unable to find a place on your website to establish an account, as the login requires an email address and a password that obviously has to be established before logging on.
Thanks.
Brian,
It sounds like you are doing to the right thing by paying attention to the process and keeping notes. Remember every wood is different as well as conditions.
1) If the wood feels hot, I’d say that’s too much. At most it should feel warm.
2) I have not heard of this product, but I’ll check it out.
3) You can join one of my eCourses here> https://turnawoodbowl.com/shop/ Or you can sign up for weekly Turning Tips here> https://turnawoodbowl.com/free-tips/
All the best to you!
Happy Turning,
Kent
I have been carving pictures in burls for a number of years. My first one was a small burl about 14 inches x 8 inches, a green red cedar burl from a growing tree, obviously very wet. An older gentleman came and told me a secret, his, for removing water from wood so I tried his method and it worked. I was making a head stone for my daughters grave and so time was critical. the process is this and I have used it many times. set your piece of wood down so it is as flat as you can, take some diesel and rub it into the wood and let it sit overnight, about 15 hours. Take your tool for evening the outside of the piece and work the surface until you have removed the immediate surface of the wood. Repeat this process for a few days and you will find the water inside has disappeared. I had to do this every day for 7 days to dry that cedar block and it never even checked let alone cracked. This process has never let me down yet after 40 years. There is no odor from the diesel and it makes the wood easier to work. I encased the head stone on fiber glass to preserve it. Don’t take my word for it, experiment with a scrap piece of wood and be amazed at what happens.
Ed,
Thank you for writing and sharing! I’m sorry about your daughter. Hopefully the wood carving/drying process was a bit of therapy that aided you during that time. This sounds like a very interesting technique. I might give it a try sometime. Thanks for sharing!
All the best to you and Happy Turning!
Kent
I am just beginning to turn green wood mainly maple after several years of turning segmented and solid dry wood bowls and found this information very useful , many thanks for the tips.
My pleasure. I’m glad it was helpful. All the best to you! Happy Turning!
I will be trying some of these tips out. Cheers
Thanks, John
All the best to you.
Happy Turning,
Kent
Hi Kent,
I live down under in Australia and am a relatively new wood turner (March 2020) and because of Covid19 am self taught. I love reading your posts and have gained an enormous amount of information on how to turn wood. Thank you.
I am fortunate that I have access to quite a bit of free wood in log form and have been reading your articles on preparing green wood bowl blanks. My question is;
Does it make any difference to the drying time, if I remove the bark completely or should it be left on.
I have also started using a “Woodcut” Max3 bowl saver, so should I cut multiple bowls in the green form and bag dry, or leave until the initial blank is dryer?
Great question. The bark is a tricky thing. If it is firmly holding onto the wood, you can leave it. If it is loose and breaking off, take it all off. I have found that loose bark invites more insects and critters to hide and it also holds moisture. It really depends on the tree species. Thanks for asking.
Thanks for the great info, Kent.
For the microwave drying technique, do you also anchor seal the end grain of those bowls prior to microwaving?
Or do you just use anchor seal on the end grain for air drying?
Mike,
That’s a good question.
No, I would not use Anchorseal if using the microwave technique. You’ll just be cooking the Anchorseal and that’s probably not a good idea.
Happy Turning,
Kent
Kent,
Thanks again for your breadth of knowledge and outstanding formats of education. I recently stumbled on your YouTube videos. Very nice.
Let’s back up the crack prevention effort a couple steps:
In the back yard is a black walnut tree with an 18 inch diameter at the bottom. The top is dead and it has been deemed by the spouse and our tree guy to be a risk for falling. As it would fall on my shop so it is coming down sometime but can safely wait until winter. I recall reading somewhere that bark stays on better when trees are felled in the winter. I also stumbled on some info that suggested cracking is worse if the tree is dropped in the summer.
1. What is the best time of year to drop the walnut tree to limit checking? (We live in Delaware.)
2. Once it is down, what should I do with it? There is a bunch of information for plankers out there and not much for bowlers. I do not have a kiln or drying box. I do not have the time to first turn all the wood right after it comes down though I suspect least cracking would be first turn early, anchorseal and second turn when dry stable. Do I cut logs at diameter plus two inches on each end, anchor seal and stack? Or cut the log, cut out the pith, seal and stack? Or cut the log, cut out the pith, turn the bowl blank and seal?
Thanks!
Hello BG,
I’d say just send me an invite and I’ll be glad to take care of that tree for you. LOL I’m just kidding…sorta. LOL
Winter is a great time to drop the tree as there will be less stress and moisture lost from the hot sun.
Once it is down, follow the examples in this article. Cut the logs about 1.25 to 1.5 longer than they are wide. So an 18″ diameter section, cut it about 24″-ish inches long. If you can, cut the pith sections out. This requires cutting with the grain straight down through the log. The larger sections will require a couple of inches, so make two cuts around the pith. There is an added huge benefit, you will get quarter sawn sections which can be amazing. See this video https://youtu.be/IWaTRYo6SUc
Depending on how much moisture is in the tree, you may find it best to wait a few months before turning. Too much moisture can also make a dramatic change after a bowl has been turned. I’ve found it’s good to let a tree mellow for a bit. That being said, I’d still be turning pieces at different time intervals to see how it’s performing.
Try to get the logs cut in half at a minimum and then seal the ends. That relieves tremendous cracking pressure. If you can section out the quarter-sawn pieces and remove the pith completely, all the better.
Best of luck with it!
Happy Turning,
Kent
Awesome. So helpful.
Knowledge is addictive and I continue to be thankful that you share yours in such an informative fashion.
BG,
Awesome! I’m so happy this is helpful for you!
Happy Turning,
Kent
Great site, Kent.
I turned 3 bowl blanks for the twice turned method from very freshly cut wet oak, stored them using method 2 after coating end grain with anchorseal back in April. I just checked them and all 3 have cracks 🙁
I had wrapped them up using packing paper, after covering them with the wet shavings. They are in a basement with humidity no lower than 45%.
Any ideas why they still cracked? I tried to make sure the wall thickness was even.
Thanks again for your great contributions to bowl turning.
Hello Kevin,
I feel your frustration.
It’s hard to say what makes some wood crack more than others.
I can tell you I also had a very fresh and very wet black cherry tree that acted similarly.
What I discovered, the hard way was to let the logs rest for a few weeks. The wood I worked quickly, in its very wet state, cracked like crazy. After a bit of time passed and the logs “mellowed” they turned more controllably and without as much cracking.
The lesson I learned was to reduce the extremes. Instead of going from very wet to rough turned, it was better to go from very wet, to cut logs (with some time), to cut blanks (some more time), to roughed bowls.
Think of releasing the moisture from the log like landing an airplane. We want to bring the moisture down slow and controlled, not all at once and immediate. Let me know if that makes any sense.
Happy Turning,
Kent
Me gusta mucho leer estos artículos, son muy completos en datos empíricos. Gracias por compartir toda tu experiencia.
saludos desde Uruguay.
“I really like reading these articles, they are very complete in empirical data. Thanks for sharing all your experience.
Greetings from Uruguay.”
Danilo,
Thank you for writing and greetings to Uruguay!
I wish you all the Best!
Happy Turning,
Kent
Hi Kent, I love your site. Thank you for all the great info on here! Like Val above I started turning my first piece and mistakenly stored it in a plastic bag. Now it’s moldy! I read your response to Val, started storing it in a paper bag, and at started spraying it with a bleach/water mix But to no avail! How can I fix this? If I turn it off and then seal it, can the mold still grow? Thanks for your help and God bless!
Chase,
Thanks for writing and for your kind words.
If you still have plenty of material to turn, yes, turn off the moldy area. If the piece is complete, you can apply an oil finish, like Tried and True Danish Oil, which is pure linseed oil. This will prevent mold, and also slow the drying process which helps to prevent cracking. Place it in a dry paper bag with no shavings (if you seal with the oil) and check the bag day-to-day to see if it’s moist. If moist, switch it out for a dry bag.
And, yes, the wood will dry with the oil applied. It’s almost as if the water and oil change places. I know that’s not exactly what happens, but you get the idea. The moisture still escapes even with the oil finish.
Let me know if that works for you.
Happy Turning and All the Best,
Kent
Thanks Kent. I will let you know! Also, is it ok to carve on a finished bowl? Do you have to reapply oil after?
Chase,
Thanks for the question. Yes, you will probably want to add oil to the freshly carved areas when they are complete.
Happy Turning,
Kent
Kent–Quick question about use of Anchor Seal. Do you use it on the end grain after you have turned bowl blanks on a band saw? I just made a bunch of blanks and I know many will not become bowls for weeks or months. Thanks for all the great info on your site.
BG,
Yes, if you know you won’t be turning them soon cover the end grain with Anchor Seal.
All the best to you!
Happy Turning,
Kent
Kent,
Thank you for the article on the various methods for green bowl drying. I’m new to turning and am wondering why you didn’t include a seventh method — vacuum drying at lower temperatures than kiln drying. Is using a vacuum to reduce the required drying temperature a good idea?
Regards,
Jim
Hello Jim,
Thanks for writing.
I’m not familiar with the vacuum and low temp process. It sounds like it might require a good deal of space and time.
Have you tried this?
Thanks,
Kent
Jim, I have used vacuum drying for wood items often and with success, but not for wood bowls. However, I am going to try it! My immediate problem is finding a large enough chamber to hold a decent size bowl. Also, there may still be the issue of uneven drying. I can assure you that it will speed up drying.
This is seriously the best most concise and clear guide I’ve come across on the web about drying green wood to turn into bowls. Thank you so much! I learned a ton. Just turned two bowls last week and trying the microwave method right now. About to try the dessicant method tomorrow.
The first bowl out of a silver Maple log I cut out the pith and turned but it was already cracked a little before turning it.
The second bowl out of green River Birch turned green very nicely but has now started to get some slight checking before I started today doing the microwave drying method. So we’ll see.
Any ideas on how to fix little cracks in bowls to still use them? Epoxy? CA Glue mixed with it’s own saw dust possibly?
Thanks again!
Hello Trent,
Thank you so much for your kind words. It means a lot to me to know this content helps you!
OK, here’s how I fix wood cracks.
If the cracks are hairline thin cracks, I use this technique.
For larger cracks, I will use this trick to epoxy fill, and sometimes I’ll even use turquoise as a filler.
Check out those articles and let me know what you think.
Happy Turning,
Kent
Hi Kent. Just split the log and am roughing out my first greenwood bowl tonight when I happened onto your site. Great timing! Thanks for the info.
I’m sure it varies, but approximately how long will a bowl (maybe an inch to inch and a quarter thick) sealed with Anchorseal take to dry?
Hi Barry,
So glad you found this site. Welcome!
Well, as you guessed there are many things to take into account to determine how long a piece will dry or equalize.
In general it takes a wood bowl blank an inch thick about a year to equalize (dry) and stop noticeably moving. If it’s really wet, you will want to help make that process more gradual with the paper bag technique. If the tree has been down for some time and the green wood is just slightly moist, placing it in a cool cabinet may work just fine.
One big thing to do, is experiment with a few pieces and see what works best. Every tree and every tree species is different, add to that your local climate and the condition the timber is in when you acquired it and things can get more complicated. Just pay attention and you will start to see certain woods responding in predictable ways.
So glad you’re here. Enjoy!
Happy Turning,
Kent
I use yellow carpenter’s glue to seal end grains on both my rough turned bowls and on the end of all the logs I drag home. I apply 1 coat, let it dry for one day and then apply a second coat. It is the best stuff I have ever tried and I have tried a lot of stuff. I also use to seal the end of green sawn lumber.
I also use my microwave oven to dry rough turned bowls. On them I do not use the yellow glue, it can make a mess in the microwave. I cook the bowl for 1 minute on high heat and then pack it in a paper bag stuffed with the shavings I turned off. I let it cool for a couple of hours and repeat the process until it is dried. I weigh the bowl before every burn and record the weigh directly on the bowl with a pencil. That way I don’t get the bowls mixed up and I can see how little it loose weigh after about 18 burns. I don’t have to mess with my wife, I have my own microwave. I picked it up at a yard sale for 5$, been using it for 5 years.
Val,
Thanks for writing and sharing your information!
I’m sure the glue works well for sealing the ends. Does it ever work too well and cause mold in the wood? And do you dilute the wood glue to make it thinner for easier spreading?
Good tips about microwaving. Marking each bowl with a pencil is a great tip and getting your own “shop” microwave is probably the best tip, at least for keeping your spouse happy. 😉
Thank you for sharing!
Happy Turning,
Kent
Having tried most methods with a fairly high failure rate I now wait for my wife to go to her Yoga session and slip my green bowl in the microwave. I use 45 second times with long in between periods for cooling. I also use desiccant beads from compressor dryers instead of silica due to cost. So far the micro wave seems to be working.
Alan,
Thank goodness for Yoga.
Watch out for Laurel Oak! I just got some from a local downed tree and it smells like old feet. Might make the microwave suspicious! 😉
I’m glad you’ve found a method that works for you.
What are compressor dryers? I’m not familiar with that term.
Thanks for leaving a comment.
Happy Turning,
Kent
Hi Kent,
Excellent article, thanks! I now turn green wood almost exclusively and prefer to rough turn and then finish turn. I frequently use a coring system so I end up with quite a few rough turned bowls at the same time. Similar to your denatured alcohol method, I stabilize my bowls in a 50/50 mix of cheap dishwashing liquid and water in 30 gallon trash cans. The denatured alcohol proved to be too expensive and, after a couple of uses it becomes saturated with water and no longer effective. I then do my second turning immediately or transfer the rough cores to paper bags of brown paper until I can get to them. I rarely have any cracking and warpage is kept well within the 10% thickness.
Although I use Anchorseal on the end-grain of the log segments in my woodpile that are waiting to be cut up and turned, it never occurred to me to use it on the end-grain portions my rough bowls. That is brilliant, thank you! I am going to try it on the next batch that I process. Thank you for sharing your experience.
Karl
Karl,
Thank you for leaving a comment and thanks for sharing your 50/50 solution for stabilizing bowl blanks.
I have a couple of questions.
How long do you typically leave the bowls in the solution? 50/50 sounds like a LOT of dish soap. What type of soap do you use and about how much do you mix up at a time?
Great information! Thanks again.
Happy Turning,
Kent
I’m a beginner and this is very helpful information. Thanks!
Hey Gary,
You’re welcome. Thanks for the compliment!
Happy Turning,
Kent
Thank you for this article. I’m new to green wood turning and have been reading about drying green wood only to end up confused by all of the different methods and opinions. Your article quickly cleared my confusion.
Roger,
Thank you for reading my article and sharing your findings.
What other wood bowl turning topics are you interested in or finding difficult to get good information about? I’m always looking for viewer-driven questions and issues to help create the most helpful, relevant and useful articles.
Thanks and Happy Turning,
Kent
I am new to wood turning. I have 2 blow that have molded on me. How can I kill it?
Mike,
Thanks for the question.
Be sure to place the bowl in a ventilated area and not in plastic. Paper bags work well. If it gets wet, change it out with a dry paper bag.
1-gallon water to one cap full of bleach solution sprayed on the wood surface should stop the mold.
Let me know if this works for you.
Happy Turning,
Kent
Hi Kent,
Great read and learned loads from reading your article. Can I ask your opinion on green burl, I came across a large fallen branch that was full of burls ( beech I think ) I have cut it all up and got enough for around 30 bowls from it so now I need to work out what’s the best thing to do with them. I have rough turned 3 of them leaving a 1 inch wall on them and they are quite wet so my question is – do I turn all 30 of them ASAP and wrap them all in paper and hope for the best or do I let the blanks dry some more before I turn them. Many thanks , Dave.
Dave,
Great question!
Please keep in mind every tree is different. I think you can try experimenting first before turning all the pieces. Burl is very random and not uniform like straight growing wood fibers. So, burl doesn’t deform like regular wood.
I’d try microwave drying a roughed out blank or two and see what they do. Check this out https://www.youtube.com/watch?v=0X5xyq2ikzY
In general, you want to turn cut wood as soon as possible as decay, dryness, and other factors work to deteriorate the material the longer it sits. But with burl, you may have a bit more time to work with.
Let us know how it goes!
Happy Turning,
Kent
Kent,
Great information. A book that may be worthy of the gifts for woodturners is, “Moulthrop, A Legacy in Wood,” by Kevin Wallace. In it there is a description of their drying technique. This involves a formula of polyethylene glycol (PEG 1000) and water. After soaking they place the vessels in a room with a dehumidifier. Granted not something the novice need try early on, however, I am very interested in your thoughts on their method.
Enjoy,
BG
BG,
Thanks for the heads up on this book. I’ll check it out.
Like I try to stress throughout my site, I think we each need to do what works best for us. If you can dry something effectively by placing it on a shelf and waiting, great. However, it is nice to know as many different ways as possible and then find what works best for you.
Thanks for the input!
Hi Kent,
Have you tried vacuum drying wood blanks?
I’d like to try it, but I’m not sure I should invest in the equipment, if I’m not sure if it will work.
Simplified, Vuccum canister & Vaccum pump, APX 1 week per inch
Do you have any advice?
Kevin,
This is a new one to me. I have not heard of that technique, but I will be investigating it for you. Stay tuned.