Rough Turning Green Bowls

[Marty Tippin]

When you rough turn a bowl blank, how much shaping do you do and how concerned are you with allowing for whatever "final" design you might intend?

I'm ready to move past the warping and twisting of finish-turned green bowls, but not sure how much effort I should be putting into the rough-turned blanks that I'm going to set aside for months to dry. And I really don't want to find out in 6 months that I should have done more (or less) a long time ago... :rolleyes:

[Scott Hackler]

The rough shape should be the same as your desired final shape....only thicker. General rule of thumb is 1" of thickness for each diameter of the rough out. So a 10" rough out should be left 1" thick...everywhere. No sharp edges, round everything and concentrate on consistent wall thickness. For OUR area, I found the "just bag it" and "put it in the shavings" doesn't work very well. My solution, through trial and error is Denatured Alcohol soak over night and wrap up in newspaper and stuck on the bottom shelf (in my climate controlled shop) for 4-6 weeks. Then the moisture content is low enough for final turning and such. Using this method I have about 98% success rate with no cracking and minimal warping (unless you turn Hackberry, side grain... then forget about staying round!)

[Prashun Patel]

I usually leave about an inch of wall thickness. I rough out the general form (like the shoulder height and the return), but make no sharp details including the rim edges.

I pay careful attention to the bottom, going a little deeper to account for the tenon (if you are using a tenon).

I am lazy both to prep and to finish turn, so a quick wax and a long wait works very well for my storage.

[Marty Tippin]

Think I'll give the denatured alcohol method a try. I've got a big stack of logs waiting to be roughed out and there's no way I'm patient enough to wait 6 months for them to dry naturally... ;-)

[Dennis Ford]

In addition the to DNA method, you might try just putting some in brown paper wrapping. This works great for elm, pecan, walnut, maple etc. not so good for fruit woods. In warm weather, rough-outs in brown paper are usually dry in two months.

[John Thorson]

All great advice above, one more point is to make sure the inside of the rough turned bowl dries faster than the outside. The waxing or sealer is usually just on the outside, newspaper wrap, etc. is on the outside. Basically it will shrink when drying and if the outer surface dries faster than the core or inner surface... it won't stretch so it will crack. The 10% rule is to leave you with enough thickness to finish turn when it goes oval as it dries. Some woods don't go as oval as others, some processes keep the bowl from going too oval (boiling or DNA mentioned above) and you can cheat a bit on the 10% rule and things will dry down faster. A 'balanced grain pattern' will help it kept from going into a wonky off-center oval as it dries. Close to the floor is the most humid, 1 foot up a bit drier, 3 feet up a lot dryer air. Some are going to crack or check on you, if I don't lose more than 10% I feel like I've done well, if I lose 20% of the rough-outs... well I've cut some corners. Make sure you eliminate the pith and don't include any checks that often radiate from the pith in the rough-out, none at all. Good luck.

You'll soon find that the fast and fluid action of roughing out a bowl is some of the most fun you can have while turning. Draw out a rough design, number the bowl as you date it and record the type of wood. Keep the drawing and you won't have to try to remember 'Now what was I thinking when I roughed this out?" You don't have to follow the original design when finish turning but I think this helps your design skills.