Preparing green bowl blanks?

Re: Preparing green bowl blanks?

John Trant (Baltimore/DC area)

>I always Anchor seal the whole thing. In my opinion, it is all end grain (at least to some degree). Some of my fellow turners will just seal the end grain and any highly figured areas.

John

Re: Preparing green bowl blanks?

Mark Kauder, Phenix City, AL

>Yes, I would Carol. Put two coats on.

Mark

Re: Preparing green bowl blanks?

Chris Lee

>I was under the impression you only sealed the end grain. If you sealed the whole blank where does the moisture go? Never done it that way so just curious?

Chris

Re: Preparing green bowl blanks?

Mark Kauder, Phenix City, AL

>I agree with that method after the bowl has been roughed out. That point, you are trying to equalize the escape of moisture so that the drying process is controlled. Because wood has been removed from the inside of the bowl, there is some flexibilty so that the bowl will warp rather than bust.

However, if you are only going to cut the blanks from the log, and maybe round them on the bandsaw, I think you need to reduce moisture loss until you can rough it out.

Mark

Re: Preparing green bowl blanks?

Jim Pugh, Ohio

>Carole, sealing with anything is only a temporary measure. If you can't start roughing out within a couple of weeks I would put them in plastic bags and even then check them on a monthly basis.

Re: Preparing green bowl blanks?

John K Jordan

>>If you sealed the whole blank where

>does the moisture go?

I've bought them that way and that's the way I've done mine. After roughing out a bowl, I seal it again and it even when sealed all over the blank still drys out and warps as expected.

I think the theory is that the sealer will not STOP the moisture but slow it considerably. Drying quickly causes a more rapid moisture loss in certain areas (especially around the end grain) so those areas shrink quicker and increase internal stress. If the moisture escape is slowed all over, moisture can slowly suffuse throughout the wood so that no one part is very much dryer than another part, so shrinkage is more even in adjacent areas. The shrinkage will never be exactly the same in all directions, but there should be much less internal stress and less chance of distructive cracking and spliting. Seems to make sense.

Putting it in a bag should have somewhat the same effect - the humidity in the bag should remain relatively high so moisture escapes more slowly from the wood.

I've never studied kiln drying so I don't understand why lumber in a kiln doesn't explode into splinters! I suspect the humidity in the kiln is carefully controlled. Perhaps the heat causes the moisture to move more quickly within the wood to maintain internal equilibrium while drying more rapidly. I'd like to know just how kiln drying works.

JKJ in East TN

Re: Preparing green bowl blanks?

Carole in VA

>

After roughing a bowl, I seal ONLY the end grain. I think this evens out the moisture loss. End grain looses moisture a lot more quickly than long grain, so sealing just the end grain balances the moisture loss between the two and you don't get quite as much distortion. Sealing an entire rough-out would not do anything to compensate for increased the moisture loss from the end grain vs long grain so you would still get warping, just at an overall slower rate.

Re: Preparing green bowl blanks?

Ace Foster in Ben Lomond 95005

>You'll be better off to seal the whole blank. You'll also be better off to cut the blanks in such a way that the pith is cut away. Any time you have the center of the tree (or branch) in a piece of wood, it's apt to check.