Turning Burls into Natural Edged Bowls Check out my Blog posts
I specialize in turning burls and many people have asked me for advice on how to best do this. Every burl is different so there is not a simple formula. There are two main types of burls, ones that wrap completely around a log and ones that are mostly on one side of a log. I like bowls with natural edges so my approach is to visualize the rim of the potential bowl as I analyze a burl. My natural rim requirement significantly limits the possibilities. The following images and comments show several real examples. Please contact me by email for help with your burl and include photos. The actual size of the burl and the size of your lathe obviously affects the possibilities. The examples below are for small to medium sized (15" diam) burls. Larger burls (over 20") require more complicated cutting or a very large lathe. In my STORE I show images of many burl bowls and their burls with descriptions of the turning process. Check this out.
Cutting a Burl off a Tree or Log: If the burl is on one side of the tree and covers less than about 25% of the circumference, you can safely cut the burl from the tree with a chain saw without harming the tree. Cut the burl flat and keep a clean bark edge (see image below). If the burl wraps around the tree, you will need to take the tree down. Burls do not rot as quickly as the bole of a tree so I often take dead or nearly dead trees down to harvest solid burls. If the burl wraps around a log, cut the log a few inches or more from the burl on each side (see image below). Store cut burls in a garage or shed out of the sun and seal the end grain parts of logs. I prefer to turn green wood so I keep burls and wood from drying out if possible.
Burl on One Side of a Log: There are two main approaches depending on the shape of the burl that you cut off the log. The base or bottom of the bowl can be positioned on the top or on the cut flat bottom of the burl. The following examples show the difference.
Click on an image to enlarge it.
The above images show the flat part of the burl attached to the head stock of the lathe, giving a bowl with an unsymmetrical rim. If the burl was mounted on the lathe with the flat cut part of the burl toward the tail stock of the lathe (images below), a bowl with a round edge shape would result (see top view of bowl below). The side view of the bowl shows how the bark edge gives a great bowl with a smaller diameter and greater height. For me, the choice depends on the actual shape of the burl and the thickness of the bark. Note: I secure burls to the lathe head stock using either a face plate or an Elio drive. The tail stock is required with the Elio drive, but I also use the tail stock with a face plate for safety since burls often have decay and inclusions hidden inside.
Burl Wraps Around a Log: In this case I cut the burl perpendicular to the axis of the log to give two or more cross sections of the burl for end grain turning. The pith of the log will be near the center of the bowl and the outer rim of the bowl will show the outer contour of the burl. If the burl has a large diameter you will need a lathe with a large swing or use a different cutting strategy. For example, the burl could be cut parallel to the axis of the tree, giving a piece similar to the examples shown above.
Below is a 17" diameter cherry burl that was cut into two pieces with a cut perpendicular to the axis of the log. One of the pieces is mounted on the lathe with the head stock to the right so the base or foot of the bowl is to the left.
The next images show the bowl from the above piece. The pith of the log is in the center of the bowl and the outer bark rim follows the outer contour of the burl. This burl will yield one more similar bowl.
Burl is Enormous: If a burl is too large for the above techniques, you have to study the burl and visualize potential bowls and cut the pieces accordingly. This is easier said then done, especially if you insist on bark edged bowls as I do. The following image shows me cutting an enormous black ash burl that measured about 4' x 6'. I got about 15 bark edged bowls from this burl, some 24" in diameter.
Recent Examples of the Process of Turning Burls into Bark Edged Bowls
Aspen Burl turned on March 19, 2017: The following images and brief comments show the process of turning this challenging burl into a bowl. The burl was about 17" long and 12" wide and was unfortunately cut a bit short on one side by the logger. I decided to turn a bowl with the bark edge toward the bottom (tree side) of the burl even though the bowl will not have a complete bark edge due to that short cut. The alternative approach would be to have the bark edge of the bowl on the top (bark side) of the burl. I decided against this approach since some of the bark on the top of the burl was damaged in the logging/cutting process, the bark was not thick and gnarly, and I wanted to turn a larger bowl.
The next three images below show the burl that was cut too short on the left side, the burl mounted on the lathe so that the top of the bowl is toward the head stock of the lathe (to the right in the second image), and a view from the tail stock end showing where a 3.25" diameter tenon will be turned. In the second image you can see the three pin Elio drive I used for attaching the burl to the lathe. This drive permits easy manipulation of the burl to get it oriented properly. This drive requires the use of a live center in the tail stock.
The next two images below show the turned outer profile of the bowl with its tenon, and a side view of the reverse mounted bowl using a Oneway Stronghold chuck secured on the tenon. You can see the straight barkless part of the burl in the first image that resulted from the poorly cut burl. This will result in a bowl that does not have a complete bark edge.
The next two images show the hollowing process. I start out with the live tail stock center attached to help stabilize the burl. Many burls have decay and voids and can break loose from the chuck, so the presence of the live tail stock center will help prevent this, but it obviously has to be removed to complete the hollowing. I keep the live tail stock center attached during the turning of the outer perimeter where the torque on the tenon is the greatest. I then remove the tail stock as shown in the second image to hollow out the center part of the bowl. You can see decayed areas and frost cracks in both of these images. These problem areas had to be stabilized with thin CA glue frequently during the hollowing. Click on these images to see magnified views. It is always slow going with aspen burls. This one took about four hours to turn.
The next two images show the completed rough turned bowl. Since it was turned green it will sit in my shop drying for several months and then sanded and oiled. Aspen burl bowls never show their amazing colors and figuring until sanding and oiling, so I always look forward the the finishing process and am always blown away with the beauty of aspen burl. Note that I slightly sculpted that straight barkless edge. I do not like to embellish a bowl by carving but I think the minimal carving here gives a better look. I will also make a dark outer edge in this area by slightly burning it with a torch.
Follow-up with a different Aspen Burl with a complete bark edge: The following images will tell the story of a similar burl. The bowl has been dried, sanded, oiled an waxed so it will show how the finishing brings out the beauty of aspen burl.
The images show the burl that was cut to preserve the complete bark edge along the wide part of the burl. Images are also shown of the finished bowl. The bowl is 19" long, 12" wide, and 3" high.