Just visualizing a bowl that large... I would make it about 3/8" with a bit more on the bottom to keep the center of gravity down.

..and that is my 2¢.

3/8 sounds good. Depends on species of wood and soundness of blank.

Glenn J.

Thanks all...it's going on the lathe this weekend.  We'll see how the roughing out process goes.

Quote:





NOW YOU TELL ME!!!!!! 

Largest bowl I ever turned was 22 inch diameter. Pacific Madrone is my favorite wood, and known for unpredictable warping and cracking before you fire up the chainsaw. It finished warping at 26 by 19 inches, kind of a D shape. With that wood, it needed to be kept to about 1/4 inch so it wouldn't crack. 3/8 is a good wall thickness for that size. Much thicker and it can 'feel' too heavy. 1/2 inch thick would depend on what type of wood it is. It can make a difference in drying it.

Sounds like you are planning to turn green to final thickness rather than twice turning. If the walls are too thick, it will crack. Also, in the transition area, the extra thickness there can make for uneven drying stress, which results in cracks. I have taken to a small ogee near the base to help even that out. Also, make sure to round over both edges on the rim as the sharp edge also makes for uneven drying stresses. Stretch film on the rim is good but not for maple. Seems I always get mold growing under the plastic with maple, all that sugar in the wood. Walnut is pretty stable, but cherry, if left 1/2 inch thick may crack.

What kind of wood is it?

robo hippy

robo_hippy wrote on Jul 20^th, 2021 at 11:24am:


I prefer to 'twice turn' all of my pieces.  This wood is a 'silver maple' and is quite green as the tree was taken down within the past month.  The customer wants me to keep it as big as possible which means it could end up being 19+" in diameter and perhaps 8+" deep.  I've had good luck rough turning maple down to 3/4" wall thickness, re-sealing, and then storing my pieces on a high shelf in my garage.  I've tried any number of drying techniques and this, the simplest one, seems to work well for me here in MD.  Yes...I always rounded over the rim before storing and pay particular attention to the transition area.  One thing working in my favor is the size of the piece is so big I shouldn't have any difficulties with tool angle presentation, etc.  Either way, I'll find out for sure this Saturday once it goes on the lathe.  Definitely a chance for me to break out my large Robo tool rest. 

suggest a strength training program to use it.

  couldn't have said it better!