My first bowl warped....now what?

Tom Baugues

Member
Messages
2,794
Location
Lafayette, Indiana
So I turned my first simple bowl on Monday evening. I turned a tenion on the bottom to fit it in my chuck to do the inside of the bowl. Thursday evening I bought a set of flat jaws for my chuck so that I could reverse the bowl and finish off the bottom of the bowl. The almost finished bowl sat in my chuck on the lathe from Monday til this morning (Friday) when I removed it from the chuck to find that it had warped alot. With this being my fiirst bowl I need someone to tell me where I went so wrong.
Details:
The wood was Apple from a tree I cut down in my back yard about 8 weeks ago. I did not seal the wood at that time. The wood sat outside until about a week ago.
I knew the wood blank had checks in it before I turned it but that was ok as this was just my first attemp at bowls and really didn't expect to keep this as a usuable bowl. The turning worked out ok and after showing it here on another thread I was encouraged to finish it. I was really shocked as to how much it warped. I have read here that wood can do that but I'm guessing that I should have left the wall thickness thicker to allow for this?
When reversing the bowl in my new flat jaw chuck thw bowl wobbled all over and was no way round.
Should I have.... Only turned the piece to a rough shape then set it aside for a few more months to dry out?
Or turned the piece as I did but then seal it with anchorseal right away...would that have helped?

The walls of my turning are to thin too correct this now. I have not put a finish on it yet.
Advice wanted.

Thanks,
Tom
 
Last edited:
I suppose a wood is "green" until a moisture meter reading says it is safe to turn. Does everyone own a moisture meter too? Is there a "general" rule for drying time of a partially turned bowl? I remember reading about 1 inch of wood per year for logs but what about partially turned green bowls?

Tom
 
Tom,
The drying time is different depending on the moisture content of the wood, the temp aqnd humidity and several other factors. A lot of turner will keep a 5 gallon pail with Denatured Alchol in it and once turned green they soak them in the DNA for a few weeks. Here in Arizona I don't have to resort to that.
 
Don, the DNA soak is a day or so, not a few weeks. ;)

Tom, the direct answer to your "now what?" question is turn another, or re-turn this one until it's round again. (If there's enough wood thickness left to do so.) In your case for this bowl, it's a combination of A) apple wood likes to move quite a bit when it dries, and B) your bowl blank was not dry when you finished turning it. A real basic truth about any wood...almost any type of wood moves when it dries. Some a lot, some a little. If the wood is thick, it will tend to crack. If the wood is thin, it will tend to warp. One way or another, it wants to move. And it's not uncommon for wood to do both -- crack and warp.

There is a lot of info (some of it conflicting info) on the Internet about drying bowls. In a nutshell, the "1 year per inch rule" still applies. A bowl with 1" thick walls can take up to 12 months to dry completely. (These are general terms, since different woods dry at different speeds, and your climate has a lot to do with it, too.) There are ways to speed up that drying process so you don't have to wait a year to turn the bowl. (That's where a lot of the debate starts.)

Many turners will turn a bowl twice. When the wood is still wet, they turn the bowl to rough thickness and shape. Then after the wood dries, they put it back on the lathe and re-turn it to the final thickness and shape.

Some of us do things to speed up the drying process, like soaking the rough-turned bowl in DNA for a day or so, then taking various steps to hopefully get the wood to dry at an even rate to reduce the chance of cracking or warping. Then when it's dry, we re-turn the piece. Others soak the roughed bowl in liquid dish detergent (a.k.a. LDD) to control and minimize the cracking. And others use a microwave oven, or boil the piece in water for a few hours, to accelerate the drying times and/or control cracking and warping.

Dave Smith is the person who I believe started the DNA-soaking idea. Here's a link to an article he wrote a few years ago:

http://www.utahwoodturners.org/mags/smith-jan05.pdf

If you search around you'll see other, similar descriptions by other guys. Personally, I wrap my soaked bowl a little differently, but I think nearly everyone had a few of their own variations to the method, regardless of the method they use (DNA, LDD, microwave, boiling).

The bottom line is...welcome to bowl turning. :p :wave: Some of them warp and crack and end up being finely-crafted firewood. There are a lot of different things you can do to help prevent it, but you'll never completely eliminate it, so you learn ways to work around it.
 
Vaughn pretty much covered the gamet. If you turn a bowl green to finish it is going to warp especially fruit woods. I found for me anyway that apple moves the most. I soak my fruit wood in DNA for up to 5 days, wrap like on Dave's site and in about 3 to 4 weeks it is ready to return to the lathe to be finished. I have also started to use anchorseal after seeing Mike Mahoney at a demo and talking with him. He fully paints each bowl with anchorseal and says they are ready for returning to the lathe in 90 to 120 days. I just did one that had that treatment and sat for 181 days. It turned just fine. Since I am getting ready to retire I won't be in such a hurry to finish bowls so thought I would give the anchorseal method a go. So far with walnut, elm, cherry, ash and apple no cracks. Mike said in all his years of turning he has lost very, very few bowls. Some like Vaughn said are going to crack no matter what method you use. So you will have some artistic firewood. I don't mess with bowls that are cracked bad because life is to short to mess with bad wood.
 
Top