Customer wants 4" thick cherry for turning, kiln man warns of cracking

[Trent]

Customer wants 4" thick, I think it will be 10" - 12" wide. Kiln man advises to keep cut at least 2" away from pith. Kiln man says thicker wood is more likely to crack, and I should "paint" the entire piece to slow drying. Should I coat the whole thing with Anchor Seal? I'll be air drying for a month, then taking it to the kiln. Will it help (or hurt) to cut board into 24" lengths after milling? Thanks

[metalspinner]

I turn 4" cherry all the time.  But it is all green or airdryed.  I'm going to wish you luck kiln drying it. :D  That sure makes his turning more difficult. :-\

[low_48]

All fruit woods are really tough to keep from cracking. I bet one month of air drying won't be enough before going to the kiln, unless it's a vacuum kiln. If there are any defects or knots,  it's going to crack. I like to end coat my green blanks, then wrap them in newspaper. In a stack of size you might wrap it with burlap for the first weeks to slow the air coming through it. It really has to dry slowly and this time of year ain't going to help with warm winds blowing. I think cutting to lengths will help you get around those defects. Best deal, sell it green and let the turner worry about it. ;) Metalspinner is right, turning kiln dried wood is a bummer. The curls are hot, the chisels dull quicker, it's dusty, and it likes to get a little "chippy" on the end grain. If he is turning bowls, he should rough turn it while green into bowls with around 1" wall thickness, coat the end grain, and put it on a shelf for around a year. Then he can rechuck it and finish turn it.

[WDH]

It seems to me that the shorter the lengths before drying, the greater preponderance of checking per lineal foot.  Wouldn't it be better to keep it longer until dry, then cut to shorter length to limit the extent of the end checking?

[solidwoods]

What kind of dia log is that which yields a 10-12" wide (narrowest face) 2" from the pith.
Thats an expensive cherry log (very expensive around here)

Is it going into a kiln with other 4" (no)
Have you seen the kiln schedule for 4"? (very very long)

my suggest, make it from the center of this real big cherry log, split the pith between the 2 sides (helps with wandering pith crack),, cut to rough length, dip into a wax based sealant, air dry (about 1-2yrs)
Shame it won't go into the microwave dry method,, but conventional kiln is crazy long and has to be in with the same thicknesses.
Or go vac kiln (same batch must be the same requirement)
The turner can shorten the dry period by turning about 1" oversize ,, wax dip, wait.
Some turners do the above but no dip and they put the piece in a plastic bag,, its sweats each day,, each day they reverse the bag.
jim

[jim king]

You are asking a question that when you find the answer to you can participate on the forum from the beach via your satelite internet hookup and not work any more.

I make thousands of turning blanks a month and the only solution I have found after talking to a LOT of professional turners is patience in one form or another.  My favorite method is boiling the rough turned blanks and air drying them in the shade for a month or so under a fan and then finish them off in a kiln of whatever design.  The turning blank kiln can be an old refrigerater with a fan and light bulb in it and a few holes in the top and bottom or set them in a regular kiln after air drying.  All my blanks are vacum packed like hotdogs so they do not dry out in shipment and crack or permit mold growth.

My turnings are of exotics and must be transported by air to the States for shows or whatever.  If they are not dried properly they will pop like popcorn in the plane as an airplane has virtually no hunidity and acts as a very harsh kiln.  Due to this problem I am very careful about moisture content.  I would have no idea how to kiln dry 4 inch stock.

Take a look at my turning process on this page and also there are two pages by others about drying blanks that will help you a lot.

http://www.exoticwoodworld.com/index.php?c=static&sc=process

[Warren]

Trent,

My one point of reference is to seal the entire block and let the turner deal with how to properly dry the material to avoid splits and cracks.

Last fall I sawed out some maple turning blocks 2" to 3" thick by 12" to 16" square.  I started with non-spalted maple and sealed the entire block, all six sides.  A wood worker friend who does turnings came over and stated that I only needed to seal the ends, not all the sides.  Later, when I sawed out some spalted turning blocks I only sealed the ends and then placed the blocks in an attached, but unheated garage, next to the fully sealed blocks.   

Two weeks later went to retrieve the blocks for packaging and shipping, only to find that every one of the spalted blocks with only end seal had small to major cracks/splits.  But the unspalted, fully sealed blocks had zero issues, even tho they had been in storage longer. 

Just my $0.02....

Warren