Drying thick slabs

[Denny Nebgen]

Ok, local Amish mill had a 5 foot piece of Walnut that he would sell me for what I thought was real reasonable. I had him slice this into 4 and 5 inch thick slabs just about 58 inches long. I cut a couple pieces off the ends of two of those pieces to turn green bowls. I now have one piece 13" wide by 43 inches long and 5 and 3/4 inches thick, one piece 45 inches long by 10 inches wide by 5 inches thick, one piece 10 inches wide by 58 inches long and 5 3/4 inches thick, plus one piece about 3 inches thick by 7 inches wide by 58 inches long.

Should I try to dry some pieces in my little home made kiln, stack and let air dry for 4-5 years, then kiln dry, t urn everything I can get out of them now while green leave thick and seal for drying? What is your experience?

[Reed Gray]

Thick slabs do not dry well. Mostly because the outside dries faster than the inside which results in shrinking outside, and that makes for cracks. Even if it dries without cracking, the inside never gets as dry as the outside. You seldom see slabs much over 2 inch or 8/4 thick because of this. Some of the commercial kilns will do it though. If you are going to make bowls out of it, I would suggest rough turning the bowl or platter blanks.

robo hippy

[Denny Nebgen]

Thick slabs do not dry well. Mostly because the outside dries faster than the inside which results in shrinking outside, and that makes for cracks. Even if it dries without cracking, the inside never gets as dry as the outside. You seldom see slabs much over 2 inch or 8/4 thick because of this. Some of the commercial kilns will do it though. If you are going to make bowls out of it, I would suggest rough turning the bowl or platter blanks.

robo hippy


Sounds like sage advise. Thank you

[Earl McLain]

Thick slabs do not dry well. Mostly because the outside dries faster than the inside which results in shrinking outside, and that makes for cracks. Even if it dries without cracking, the inside never gets as dry as the outside. You seldom see slabs much over 2 inch or 8/4 thick because of this. Some of the commercial kilns will do it though. If you are going to make bowls out of it, I would suggest rough turning the bowl or platter blanks.

robo hippy

Almost sounds like Mr. Gray has turned a bowl or two (thousand!!) :>)
Stay well Reed!!
earl

[Neil Strong]

If you are going to make bowls out of it, I would suggest rough turning the bowl or platter blanks.



+1 to that.

[Dave Mount]

Without knowing anything about the sophistication of your home kiln, it's not easy to dry stock that thick in a home kiln, because you need high heat and high humidity for a long time before you can start bringing the humidity down. Heat is needed to accelerate moisture movement from the interior to the exterior of the slabs, but high humidity is needed to keep the surface of the pieces from drying too fast and checking. Although Reed may know of commercial kilns that would take this job, I'd be surprised to find one, because thick stock requires very different kiln schedules than the 4/4 to 8/4 material most kilns are processing -- they can't just throw your thick slabs in with a load of thinner material. So unless they're already drying thick stock (not common, though it is done by some), it would require a separate (and long) run which would be very expensive.

Rough turning to thin the stock out and ease drying issues is good advice. However, if you don't have time to process it all at once, or you're not sure what you want to do with all of it now, walnut heartwood is quite rot resistant and will withstand being sealed in paraffin wax (all sides) for quite some time without degrade (easily a year or more). Sapwood will last a while under these conditions, but will begin to discolor within a few weeks to months depending on temperature. The goal here isn't drying (though it will dry very slowly in paraffin), just giving you time to figure out what you're going to do with it.

John Jordan is an advocate of submerging green wood in water (e.g., a water trough) to hold it. This would be fine for walnut heartwood, but I'd expect the sapwood will discolor before very long. Freezing is an option too, though I would seal the end grain and put it in plastic for this because if left uncovered you can still get some drying and checking even in the freezer (like freezer burn).

Best,

Dave

[Paul Williams]

I really don't know if this is good advice or just one experience. About ten years ago the neighbor of a friend of mine was cutting up a massive walnut tree for firewood. He had finished the large branches and was looking at trunk sections that were between 3 and 4 feet in diameter. My friend talked to him, and he gave me several the trunk sections. Three very over loaded trailer loads and several days working my too small for the task chainsaw later I had them cut into 17x17 x7 blanks with the ends sealed. I placed them near the floor of my garage. Over the years very few cracked and the sections that did crack left big enough pieces to use. My lathe swing is only 12 1/2 inches so I had the ability to cut away any small surface cracks in the ends. I still have a two of the large sections under a table in the back of the garage.

[Reed Gray]

Some woods dry better than others. Black walnut is one of them. It tends to be very stable as it dries. Pacific madrone on the other hand, it will turn into tooth picks, curly ones.

robo hippy

[Denny Nebgen]

I have started roughing out some bowls with this walnut. I have six roughed out and sealed, six more to go, unless I just decide to leave a piece or two to see what happens.