Advice for drying log slice

[Mark Bellonby]

Am hoping for some insight into drying a log slice. I have an interesting 4 inch thick walnut trunk (about 70 years old) which I am making into a table. It was chainsawed near the tree base, and stayed outside for about 8 months. Naturally, it developed radial cracks. I made a router jig to flatten one side and get to fresher wood. This done, I chainsawed the other side, and sealed top and bottom with two coats of a wax emulsion.

My question is what drying process to use. I don't mind some cracks in the final product, but want to do final shaping (with the router jig again and then belt sander, I guess) after most of the movement has occurred. 4 years is a long time to wait. I understand that Pentacryl might reduce cracking, but may compromise the finish.

The old rule of a year per inch seems to apply mostly to plain sawn or quartered planks. It would seem that a trunk section would dry faster, as it is lots of exposed end grain.

Any helpful suggestions would be greatly appreciated.

[Rick Lizek]

http://www.preservation-solutions.com/product.php?product_id=1003&category_id=1000&source=GreenWood&keyword=Pentacryl
Pentacryl is supposed to be compatible with all finishes and glues when dried.

[Jim Becker]

The problem you may face is extreme radial splitting as the moisture content drops on a slab that is a cross-section of the trunk.

[Gary Herrmann]

Anchorseal is another option that may help with cracking and is cheaper than Pentracryl.

[Mark Bellonby]

I am not too concerned about the cracks, unless they weaken the disc so much as to cause structural failure. Cracks all the way through and more than a third across the diameter might be fatal to the piece. I have seen solid sections of trees in museums and botanical gardens which are dried and seem structurally sound.

I can't remember too many cross sections in furniture pubs. Am I mistaken?

Thanks to the already interesting responses.

[Jim Becker]

Mark, the radial cracking I spoke of is not small cracks...it's typically a major break from the edge to nearly the pith caused by variable, but significant, shrinkage of the wood as moisture is released. The break will be something analogous to a slice of pie removed from the slab...by your definition, likely fatal to the project. This is the one major reason why you rarely see slices like this that are intact...

One person posting a similar question not long ago was considering banding the slice with metal to try and keep things intact.

[Ian Haywood]

I asked this question at a chainsaw milling forum not long ago and what I was told is this. The key to drying "cookies" is slow... real slow. One guy said that he was very successful at drying cookies by keeping them in his barn at the bottom of a pile of hay for a year or more. The hay keeps air movement to a minimum and slows the drying. Another said he put his in paper bags and then in the bottom of a closet with the doors closed, again to control any air movement on the piece and to slow drying. It was also said that it had to be a near perfect cookie. Very consistent thickness and no cracks around the edges. Any existing cracks will run as it dries. I think this was with green cookies though and might not apply to something already weathered.

Ian

[Mark Bellonby]

Jim - perhaps I was misleading with the word "fatal". Unless the disk is in danger of falling apart, the concern would be aesthetic. A pie shaped void from pith to bark could be filled and not a disaster, unless too big.

Ian - in your forum, did you get the idea that the "cookies" dried quicker than conventional planks due to their orientation in the tree? I am patient enough to wait a year or two.

Anyone know if there would be a difference in the final air dried product if it had been soaked in Pentacryl?

[Rob Will]

It will not work. Those cracks will go all the way to the center and your filler will fall out. JMHO,

Rob

[Jim Becker]

Mark, when I used "pie shaped" I really meant that...it would be as substantial section broken out in most cases. Not something you could fill with anything outside of solid wood.

[Brett Baldwin]

I agree that your chances of success are small but if you don't have anything better to do with it, it wouldn't be any big deal to give it a try. Like Ian mentioned you want to slow it down as much as possible so sealed ends and an enclosed cool place is probably your best bet. Do you have a spare corner of your basement that has nothing to do for the next year or two? I'd put it in some sort of container so that you could weigh it periodically to see if the moisture is equalized or not.

[Ian Haywood]

Ian - in your forum, did you get the idea that the "cookies" dried quicker than conventional planks due to their orientation in the tree?

They didn't mention that but yes. Most of the drying occurs through the end grain. This is why you get checks on the ends of boards, uneven drying. They almost always paint the end of the logs with sealer before they mill them so they won't crack as badly. I'm told it depends on the kind of wood it is. Some is more prone to checking than others. I'm no expert tho, have been picking up on some of it by reading, but have actually done little milling. 4 or 5 cedar logs this past summer is the extent of my experience.

Ian

[Mark Bellonby]

I don't doubt the inevitability of a pie shaped void. Being an optimistic person, I consider this a design challenge, and am willing to deal with it. Also, the "cookie" is an interesting and irregular shape, somewhat like the state of Texas, so a void may not be more than more "character". The odd shape might also affect the dominance of the pie.

The piece is probably destined for my shop, not our living room, so I plan on perservering to see what develops. If the same size pie void will occur whether I dry slowly, or soak in Pentacryl, or put in paper bags, etc., I might as well put the thing on temporary legs in my shop and scrape off the wax.

[Jim King]

Patience, cover with damp sawdust or shavings at least a foot deep and forget it for a few months.

http://www.sawmillcreek.org/showthread.php?t=36506

http://www.sawmillcreek.org/showthread.php?t=38613

[Jim Becker]

Jim, you do have some advantages with some of the tropicals that you are fortunate to have available "on the hoof"...If the OP was using a mesquite slice, I'd be more comfortable that I would with something like walnut. Walnut is a little more forgiving than some species, but it do crack radially in my experience.

[Mark Bellonby]

Jim King - Now That's what I'm talking about!!

Thanks for the pics of your nice work. My walnut cookie may not be as accomodating (piewise) as your "tropicals", but it's wrapped in paper and put away for a year. Out of sight, out of mind.