Where did I go wrong?

[cme4dk]

I need some advice: I want to redo this lazy susan without making the same mistakes.  I am still not 100% sure where I messed up.
This is a 24 inch diameter cherry, with some leftover quartz from my countertop embedded in the center, flush with the top of the wood.  I finished the top with waterborne poly.

It was fine all spring and summer, but with the winter and inside heat, both sides started to warp.  I then realized that I did not finish the bottom of the wood.  I placed wet paper towels on the  bottom and overnight the warpage straightened out, but as I expected it came back the next day.  I then repeated with the wet paper towels and when the wood straightened out and was dry to my touch, I placed two coats of waterborne poly on the bottom .  The wood was straight for a week or two, but all of a sudden I noticed the cracks along the corners where the quartz inlay is.   

I want to redo the lazy susan, making sure I alternate the direction of the grain on adjacent pieces, finish both the top and bottom, but if I replace the quartz inlay, will the cracks reappear?  I’m not an engineer but I do know that they use oval windows on airplanes to reduce the stress from the sharp angles of rectangular windows.

[Ohio Mike]

I believe you are experiencing normal seasonal movement of the cherry wood. The wood is shrinking with the lower humidity of the winter season but the quartz is not shrinking. Something had to give.


Mike

[cme4dk]

I believe you are experiencing normal seasonal movement of the cherry wood.  The wood is shrinking with the lower humidity of the winter season but the quartz is not shrinking.  Something had to give.


Mike

Thanks, that makes total sense.  The cracks line up perfectly with the edges of the quartz.  I'll leave the quartz inlay out of the next lazy susan.

jay

[DaveR1]

You don't have to leave the quartz out of the next one. Just give it a little room so the wood can expand and contract without colliding with the tile.

[Lamar H.]

I was also thinking the same thing that DaveR1 mentioned, but you might also laminate a piece of 1/4" ply to the bottom of the cherry or even some solid wood panel with the grain 90 degrees to the cherry should help keep the cherry from moving.  I would do a round piece about 22" diameter.

Lamar

[jteneyck]

Route the gap around the quartz at least 1/16" larger all around and then caulk it with silicone.  That will allow the wood to expand and contract w/o cracking.  The rest of your plan is good. 

John

[Stwood_]

I did a 4x10 oak dining table with a granite 12" wide insert. I gave it an 1/8" gap. It's done fine over 10? years or so.

[cme4dk]

I did a 4x10 oak dining table with a granite 12" wide insert. I gave it an 1/8" gap. It's done fine over 10? years or so.

how did you fill in the gap?

[mr_skittle]

I'm with jteneyck. Slightly oversized hole for the quartz and caulk it in.

[Stwood_]

how did you fill in the gap?

Left it open so the wood could do it's thing. Granite insert set 1/4" above the surface of the table.
Sitting in a chair, you didn't notice the slight gap.
Insert was there so they could sit hot dishes on.