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Forum topic by Graft21 posted 04-13-2018 04:59 PM 492 views 0 times favorited 3 replies Add to Favorites Watch
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Graft21

21 posts in 1565 days


04-13-2018 04:59 PM

Hi guys,
I am making an 2 inch thick 8 foot slab table out of honey locust for my brother in law. The top will be 2 20” slabs joined together with live edge on one side.

A local sawyer milled this lumber last fall so the wood is not as dry as I would like. I am looking for feedback on my thoughts on how to put this table together to allow for the shrinkage that will continue to happen as the slabs fully dry.

My plan is to not glue the 2 slabs together. Instead, I will use elongated holes in the base to attach to each slab. I’m sure a gap will form between the 2 slabs as they dry but I can always go back next year and loosen the fasteners and close up the gap with some clamps and retighten the screws.

For attaching the slab to the base, I also plan on cutting a small dado and using cookies to attach it. As the wood shrinks laterally, this should allow for the movement.

I will not seal this table with poly. I will just use an oil (tung, danish, BLO, etc) to finish it this year. I know that next summer I will have to go back and tighten everything back up and refinish the top. If the slabs are fully dry then, I will glue them together.

Thoughts?


3 replies so far

View BobAnderton's profile

BobAnderton

294 posts in 3213 days


#1 posted 04-13-2018 07:08 PM

Since they are 20” wide it sounds like they are the full width of the tree, and they could cup/change flatness significantly as they dry. If you look at the end grain of the board, they will tend to cup such that the end grain rings will get flatter as they dry. (ie, they will cup away from the pith) This will be more pronounced the closer to the pith the boards were when cut from the log. Could be as much as 2” of cup over a 20” wide board. I don’t know how fast honey locust dries but it seems to me that it would be particularly slow drying. Most of the movement occurs as wood loses the bound water, not so much the water contained in the cells, so you may have a good bit more movement still ahead of you. I dunno, maybe I’m tellilng you what you already know.

Your measures with slots for the fastening screws sounds good. Make sure the screws can move in the slots on their own, not just when you loosen them to avoid splitting of the top.

-- Bob Anderton - Austin, TX - Nova 3000 lathe, Alaskan Mark III mill, Husqavarna Saw

View MNgary's profile

MNgary

313 posts in 2839 days


#2 posted 04-14-2018 05:35 PM

The oils you named, Graft21, penetrate into the wood and form an impermeable layer which, I think, will impede drying. However, finishes are one of my weaker areas in woodworking so my advice is to be sure you check with someone having extensive knowledge on finishing green wood.

-- I dream of a world where a duck can cross the road and no one asks why.

View msinc's profile

msinc

567 posts in 926 days


#3 posted 04-14-2018 06:42 PM

The old stand by is one year per inch, so 2” thick slabs a year into drying are half way there. That said, I have dried a few big live edge slabs in my time and one thing I have noticed is that unlike thinner milled boards, heavy slabs tend to either move in the first year or they don’t. Many of mine just didn’t move at all or at least they didn’t appear to. Don’t get me wrong, I have some that moved quite a bit, they usually cup exactly as posted above. I am not saying to go ahead and build with slabs that are half way dried, but again, based in what I have seen if they don’t move much the first year then they are not too terribly likely to move a lot the second. Best of luck.

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