Relieving stress in a 2" slab

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Forum topic by RussellAP posted 09-26-2014 02:23 PM 1341 views 0 times favorited 6 replies Add to Favorites Watch
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3104 posts in 2286 days

09-26-2014 02:23 PM

Hi Jocks.
Need some advise from people who have worked with hardwood slabs.

I have a customer that commissioned me to put a 2” thick by 8’ slab which is about 20” wide and is pecan for a counter behind his sink.

I have the slab and have been working the natural edge to get it revealed.

The place I bought the slab said to put some one inch deep cuts with a circular saw down the middle of the back side of the slab leaving two inches between cuts. Kind of like a dotted line.

Before I do this I want to make sure its the right thing to do.

The slab is wide enough to go from one end of the tree to the other with sap wood on both sides. Heart wood in the middle.

How would you relieve the stress towards cupping on a slab like this?

-- A positive attitude will take you much further than positive thinking ever will.

6 replies so far

View rick1955's profile


264 posts in 1430 days

#1 posted 09-26-2014 03:23 PM

How long since being cut down? 1” a year for air drying. If it’s still wet there is nothing to relieve stress. Furniture grade is 6-8% Air dried is around 10%...

-- Working smarter with less tools is a true crafts person...

View RussellAP's profile


3104 posts in 2286 days

#2 posted 09-26-2014 03:36 PM

Rick, I’m confident that it’s been air dried and then kiln dried by my sawyer. Looks to be a very stable piece. My main concern is that the advise given by the sawyer to cut some stress relieving slots on the bottom side could just as likely release stress as relieve it.

-- A positive attitude will take you much further than positive thinking ever will.

View Aj2's profile


1390 posts in 1798 days

#3 posted 09-26-2014 04:10 PM

Hi Russel,I would not kerf the back,that would be last resort.What I do with large slabs is let them rest in a spot in my shop were I check them every couple days for movement.I like standing them up.When I get ready to work the wood I take a hand saw and cut of the ends.I will see the stress in the saw kerf if it’s bad I let it rest longer.What ever I do to one side should be done to the other.Sand or place both sides.Go after the high spot first.
Patience is the key give the tree the respect It deserves it’s still has some life treat it right and it will be fine.When I get the piece of wood to its finial shape close out the cells.ASAP. Pecan is beautiful wood and worth the extra effort .Aj

-- Aj

View mahdee's profile


3883 posts in 1767 days

#4 posted 09-26-2014 04:17 PM

I think your sawyer gave you good advice, although I’ve never done it. It makes a lot of sense since the top surface will be exposed more than the bottom. Hopefully is not going to be laid on a solid surface instead of cabinet frame.


View pintodeluxe's profile


5661 posts in 2813 days

#5 posted 09-26-2014 04:30 PM

Slabs + kitchen application near water = the slab will move. Offer no guarantee and have the customer sign a disclaimer that this application is not normally recommended.

I have never had to kerf slabs before, but I always leave room for them to move. Kerf cuts are commonly used on wood decking material, so there must be some science to it.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Dallas's profile


3599 posts in 2487 days

#6 posted 09-26-2014 04:52 PM

I made a bar top out of white oak for a bar in Montana many years ago. I kerfed the back like your sawyer mentioned. After doing that I let it sit another six months to watch for movement, sure enough, there was some but no major cracks developed.
I used stuff called “Bartop” coating to finish it. I stopped at that bar about 16 years ago and the bar top looked just like when I made it.

Maybe I was just lucky, but it held up for at least 20 years before I got to check it.

-- Improvise.... Adapt...... Overcome!

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