boil'm or steam'm

[Raym]

Once I get the dehumidification kiln running (waiting on power) I plan on sticking some rough turned bowls (usually turned to about and inch or so) in there with drying loads to dry. I have the option of steaming them or boiling them first. which is better or does it matter. My understanding is that the moist heat breaks down the membrane surrounding the cells and will allow it to dry quicker/better with less loss to cracks. Any thoughts?

[drobertson]

Never have done either, only talked with a turner, sawed some burl for him.  He said he used a microwave, and a moist towel,  Sounded crazy to me, he says it works great.    Just a thought,      david

[GeneWengert-WoodDoc]

We do sometimes steam wood prior to drying, especially thick pieces, to try to relieve stress, but it does not work well.  Nothing special happens within the wood other than some relaxation.  The cell membranes do not change.  What does happen is that you have a lot of heat when you take the piece out of the steam or boiling water and this causes the loss of quite a bit of water almost instantly.  Long steaming or boiling can reduce the moisture to around 25% MC.  This drying can even cause cracking.  Do you want this fast drying?  Also, we know that rewetting can cause serious cracking, so if the bowls are not soaking wet (probably not that wet in your case) this does not make much sense.  In other words, I see risk but not much benefit.

[red oaks lumber]

bowl turner around here,rough turns them green then buries them in kitty litter for about a month. stirring them every week. his theory is the kitty litter removes moisture at a slower rate and the fact its buried it isnt exposed to the dryer air.

[mesquite buckeye]

One of my big drying secrets is to put figured blocks like turning wood and gunstocks either stickered or tilt stacked inside a conex (big steel shipping container). The day/night temperature variations are reduced and humidity from the wood raises the internal humidity of the container so the material drys almost perfectly where otherwise it would crack badly, even when anchorsealed. More: 1. I never fill the entire container with material, probably never over 20% filled. 2. I live in a desert, so the normal humidity is frequently 20% or below. You may get a bunch of moldy wood doing this in a moister climate. 3. I think you could use the technique in a moister climate with a dehumidifier. But then, duh, you have a dehumidification kiln, don't you.

Just sayin. ;D

[Raym]

Well it looks like my first experiment will be to just stick them on a shelf with a load of lumber and see what happens. I was thinking that boiling them or steaming them first would help stabilize them from cracking but Dr. Gene squased that idea. 

Man wouldn't it be great to have him as a neighbor? But then again with these forums everyone is a neighbor!!

Maybe experiment #2 would be to rough turn both halves and boil one side and not the other and see what happens.

[SwampDonkey]

Some fellows stick the partly turned bowls in a paper bag and place on a drying shelf. I know one member here (actually another couple that are less frequent on the forum as well) that has a room full of either partly turned bowls or rounds. ;D

[GeneWengert-WoodDoc]

Some turners also place them in a freezer, which also provides slow drying as the ice sublimes (converts to vapor without first being a liquid).

[Den-Den]

I turn quite a lot; usually coat rough-outs with anchor-seal and dry them under a shed with very few problems.  I have tried boiling rough-outs when someone wanted turnings from their post oak.  Post oak is very difficult to dry without major cracking.  It did reduce cracking and shortened drying time (did not reduce warping), it seeming like more trouble than it was worth for most woods.  Madrone is commonly boiled (also very difficult to dry).  Search for Steve Russel for more information on boiling wood.  I would guess that steaming could help also but have no idea of time or temperature needed.

[mesquite buckeye]

How about freezing, then applying a vacuum? ;D