One of the Woodturning Basics Facebook group members had a question regarding wood bowl drying and blank drying. I’m a little late with my reply so I thought I would post an answer here.
One thing to remember about drying wood for woodturning is that it is almost always different for each project. That is, same wood species, same size blank and same bowl blank shape …..seems they all dry differently. Sometimes you get cracks and checks …..sometimes you don’t. However, there are some things you can do to get similar results on a consistent basis.
You can approach the subject of drying wood from many levels of understanding. There are FB groups that focus on nothing but drying wood, you could start your own blog if you had an intimate knowledge of drying wood. For our purposes, drying wood for woodturning can be very basic or can get somewhat complex depending on how you want to approach the subject. Some turners will turn green wood to finished size and shape and call it quits …. and some turners will take it to the other extreme of needing to have a bowl blank that is totally dry and acclimated to the humidity in their shop before they will turn and finish a bowl.
I like to keep my woodturning fun! I want to enjoy the process and not get too caught up in details other than safety!
For me, turning green wood is a lot more fun than turning a dry, rock hard piece of wood that requires you sharpen you tools every 15 minutes…….but that’s me.
And, I like to turn finished green bowls. Let them dry, warp and hopefully not crack. However, when doing it this way I turn with a recess so I can chuck it up if it cracks and needs repair…… others will say that is not the way to turn wood …..but it works for me 🙂
Anyway, I thought I would post some ideas, thoughts and videos on how others approach using things like anchor seal, paint and wax for sealing and drying their wood turning blanks and bowls…..so let’s get started!
Anchor Seal and Drying
Wood Bowl Blanks
Bryan, sorry didn’t reply to your txt ….had some outpatient surgery, been in and out of it for last couple days.
Is the wood bowl blank roughed out? In other words, did you roughly turn the bowl with the thickness of the walls of the bowl being 10% of the width of the bowl. So if you were turning a 12″ bowl (roughing it out) the wall thickness should be somewhere around 1-1/4″.
You really don’t want to put anchor seal or any other wood-sealant on a rough turned bowl. You will want to dry it using the shavings in a bag method, you could try to put the bowl on a shelf, floor level to mid floor say 4′ up and see how it is drying …..if it starts to crack, throw it immediately into a bag or box of shavings.
There are a handful of products used to seal end grain on wood from trees to keep it from drying too fast and therefore cracking and checking. Anchor Seal is one of the popular sealants to use for end grain sealing, however, check out what is available for end grain sealers if you have an unusual situation and for a greater variety!
Make a Portable Kiln
For Drying Wood Bowl Blanks
There is a guy who sticks a light bulb in a box along with the rough turned bowl and sometimes a small fan, he will put a thermometer in there and he will have a vent hole in the box someplace. Basically you are setting the bowl on a table, putting a light bulb (40 to 60 watt incandescent) and puts a box over it. It seems that he will dry a rough turned bowl in 5 to 10 days….again, weigh the bowl and write it down, watch to see how it is losing water weight.
Rick from the youtube channel RickTurns makes a quick, easy, and very inexpensive drying box for bowl blanks!
Check out Sam’s kiln from the Youtube Channel WyomingWoodTurner
Microwave Treatment for
Drying Wood Bowl Blanks
Another method for drying your woodturning blanks is to use a microwave. I have experimented with this using oak and cottonwood with some good results. Again, weight the bowl to start with….nuke it at 60 seconds 3 to 6 times, again….experiment to see what works for you. Then increase the time to 2 minutes per nuke. Do not let the bowl get “hot” you will literally see steam coming off the bowl.
I’ve done bowl blanks in the microwave that have been finished in one day and I’ve done bowls that I dried over a week or so…… the slower you do it the less likely it will crack! Sometimes I will start the drying process by nuking in the microwave for a day …usually working at night, and then set on the shelf for a week or so……I will usually keep track of the daily weight loss, I write it directly on the bowl or a piece of masking tape on the bowl. I picked up my scale from Amazon, use it all the time ….even when I do some cooking 🙂 I think this one will actually weight up to 100 lbs or so …… if you are serious about turning wood and want to process your own local woods you need a scale
No Anchor Seal or Paint
on Rough Turned Bowl Blanks
All the above drying methods are for naked wood…..no anchor seal or paint.
Drying and Storing Your Wood
Logs Using Anchor Seal
If I cut a log in half, or cut a log so the pith is cut out and I have 2 pieces, I will then usually store the log outside (under a tarp if I can) or inside in an area I try to keep my future log blanks in. These are the pieces that I seal both ends of the log to keep from cracking.
I will even paint or use anchor seal on logs that are 4 foot or longer that I have laying around waiting to be processed. Sometimes I get to them quickly, other times it might be 2 years in which case, as the log is sitting there I will put another coat or two of anchor seal or paint on the ends of the log to keep it from drying quickly on the outside and causing cracks and checking.
Circular Bowl Blank Preparation
Drying circular blanks that are cut from a half log can be treated in a different ways when it comes to drying.
I’m assuming you have half a log, you either use a circle jig for your band saw or you draw a circle on the flat side of the log and cut it on your band saw.
So now lets say you have a 10″ wide bowl blank that is circular shaped and maybe 5″ inches deep. This is how I store these types of blanks. I will apply anchor seal, wax or paint to the outside of the bowl blank, on the 5″ side all around the bowl blank. That leaves 2 sides with no treatment, the 10″ circular top and bottom. Often times one of those will be covered with bark. Feel free to strip the bark if you are not going to make a live edge bowl.
Seal the entire circumference of that bowl blank. That will include end grain and side grain. It will dry, but slowly dry because you have the top and bottom of the blank exposed to air. I am usually not so much interested in drying the piece but more interested in keeping it from cracking and checking. You can store this piece indoors or outside for years. If I have gone to the trouble of cutting a circular bowl blank I usually will store these inside.
Drying Or Storing A
Wood Blank With Stretch Wrap
I also have gotten good results with using shrink wrap or packaging stretch wrap around the outside circumference of the bowl blank. I wrap it several times with the plastic wrap and set it aside to be stored or dried. I have had most of them develop some type of mold under the plastic wrap but when turned on the lathe the mold is gone.
I’ve checked blanks wrapped with plastic for weight loss and they do lose water weight over time. I think I prefer anchor seal or paint over using the plastic shipping wrap, although, the shipping wrap provides a quick solution to sealing up bowl blanks…..you can always rip it off and apply the anchor seal or paint. If you don’t mind a little mold, go with the plastic stretch wrap especially if you plan to turn it quickly and the wrap is there just to keep it from cracking or checking.
I use the stretch wrap when I cut a bunch of round bowl blanks that I plan on turning over the next week or two. Just so happens that some of them were never put on the lathe and sat wrapped in plastic for a year. These blanks did not crack and lost water weight…..but they grew mold.
Final Bowl Blank Drying Thoughts
There are 2 schools of thought when it comes to turning wood. Turning wood bowls with “dry” wood bowl blanks and turning bowls with “wet” bowl blanks. In either scenario you would like to turn the bowl blank while it does not have any checks or cracks, so treating and storing your wood and bowl blanks becomes a matter of “what works” and it is a priority!
First method, lets say you have a 5 foot log.
You can turn 12″ bowls so you cut 12″+ pieces off the log. If you want 2 bowl blanks, cut off one 12″+ piece. Then get your anchor seal or paint and seal up the fresh cut on the log.
If you are turning the bowl blank wet then you don’t need to do anything except cut a circular bowl blank and put it on your lathe. Turn it and then dry it as you desire. No need to use any anchor seal, wax or paint ……unless you want to preserve the round rough turned bowl blank as it is. If you seal all edges it will probably stay as it is….moisture wise, and will not crack. You can put it on the lathe any time and then dry as desired.
My Wood Bowl Blank Cracked and Checked
When I first started to work with wood bowl blanks almost all of them cracked and checked so I learned how to turn cracked wood bowl blanks and make repairs. This is really another matter but don’t throw out your bowl blank because its cracked!
Keep in mind however, depending on how bad it is cracked or checked you might need to do the repairs before you turn it so it doesn’t fly apart while on your lathe. Otherwise I usually will turn the piece to rough form, then use CA and coffee grounds, shavings or sawdust to seal and glue the crack together. The cracks can actually make the piece look better 🙂
If you are not familiar with CA glue, here is a CA glue starter kit that will help you get started using CA with your woodturning projects.
Oak wood bowl with cracks filled with CA and coffee grounds.
Free Wood and How to Dry It In Your Small Shop
Shawn (I think that’s his name) from youtube channel “worththeeffort” has a couple of great videos on how to process lumber from local trees for woodworking and woodturning. He is a great teacher and explains the concept behind drying wood so that you can understand the reason for the madness of drying wood 🙂
I noticed he recommends coating the end grain in his rough turned bowl blanks before putting them up to dry. Number one, you need to be able to identify the end grain ….#2 I’m not so sure that is necessary. However, its up to you to experiment with drying your wood bowl blanks and what works for you and the wood you are working with.
I will post 2 videos from Shawn’s channel. One he talks about drying in general and #2 he talks about building a kiln from an old broken freezer case. Something I plan on doing soon!