The Trouble with those Pesky Aspen Burls
Aspen burls are hard to find but that is the easiest part of turning one into a bowl. Aspen burl bowls are spectacular with amazing grain figuring and colors, but they are among the most difficult burls to turn. This is why you don’t see so many bowls made from aspen burls. Never the less, these are my favorite bowls by far and I always turn the burls green. Here is a recent aspen burl bowl and I think you can see why I love turning them.
Most aspen burls are partly decayed, but this decay is usually hidden on the inside, making the choice of how to mount the burl on the lathe important. Many of my aspen burl bowls have holes/voids/bark inclusions which are OK and often charming, but if the decay happens to be located near the bottom of the bowl you have a problem with chucking the piece for hollowing. There are ways around this problem, but it certainly will slow down the turning process. Most aspen burls have decay just under the bark and also spread around randomly. You need to use a lot of thin CA glue to stabilize these soft areas. I do this often as I turn the burl. Most aspen burls also have frost cracks along the darker grain lines causing chunks of the wood to become loose or flying off during turning. I apply CA glue into these open grain lines as I turn. I do this often during the turning process. Some I fill with fine dark wood dust (or finely ground coffee) and CA glue to help hold the wood together. This process is repeated as needed while turning the profile and during hollowing. This really adds a lot of time and expense (CA glue) to turning an aspen burl bowl. Patience is certainly required. It is also important to have your tools sharp as this type of punky wood dulls them quickly. I sharpen every 10 minutes using a light touch with a CBN wheel.
Aspen burl bowls generally do not crack during drying but the stabilized soft areas will need a bit more CA glue as they dry. This minimizes shrinkage in these areas. I often add some black wood dust or finely ground coffee with CA glue to these areas of they shrink.
I turned the following large aspen burl recently and had to resort to some unusual fixes to get a complete bowl. This burl had the usual decay and frost cracks but unfortunately it also had a large decayed (rotten) area in the bottom of the bowl. This was bad luck and caused an actual hole in the bottom. It also made it impossible to turn a base for the bowl. This large (24” x 15”) bowl was so beautiful I decided to add a new base turned from black walnut and some black filler (artfully textured by hand) to patch the hole. You can see this in the photos of the bowl below. I generally do not mess with a bowl since I like to have a completely natural bowl. I would normally use such a bowl for firewood, but it is a large beautiful aspen burl bowl, worthy of saving. I just could not toss it out. I am sure someone will love this bowl! This one holds the record for the number of hours spent turning, sanding, modifying, oiling, and applying beeswax/walnut oil.