Walnut table is bowing!

[Stwood_]

I've never trusted (young 2 year old) air dried, wide lumber for any furniture applications.
Now if it was 20 years air dried, probably.

[jteneyck]

I've never trusted (young 2 year old) air dried, wide lumber for any furniture applications.
Now if it was 20 years air dried, probably.

Where I live AD wood will never go below about 12% if it's stickered outdoors.  The only way to get it down to 6 - 8% is to put it in an environment with a  low enough RH to do that.  That usually requires bringing it into an indoor environment.  

John

[Stwood_]

Where I live AD wood will never go below about 12% if it's stickered outdoors.  The only way to get it down to 6 - 8% is to put it in an environment with a  low enough RH to do that.  That usually requires bringing it into an indoor environment.  

John

Same here. 12% outside.

[petertay15]

OP here. Appreciate the discussion and questions. I have sawed off on all four sides the extra board that was added for visual thickness. Those boards were not straight grain. I thought that under the table would be a good place to use up squirrelly lumber. I’m thinking now they definitely shrank at a different rate than the top boards. So... amateur construction, lack of experience can be blamed somewhat.

Several have asked about the heat in the room. House has hot water radiators; the gas fireplace in the photo is not used. But I think the real cause of the problem has been discovered. I said in my first post that both top and underside were finished with Arm-r-Seal. Now that the table is in the shop, it appears that the underside has stain on it, but nothing more. And I know how that terrible oversight must have happened. The table project was carried out at grandson’s request, as he wanted to learn about woodworking. But we were under pressure to get the table finished in time to be used for food service in a family wedding. The finish on top was still drying just a few hours before the table was put in the banquet hall.

Then after the wedding, they took the new table home. I guess we all assumed it was finished. As I said, it was an amateur mistake to forget that last important step of finishing the underside. But the warping is still seems mysterious. If the underside lost more moisture than the top, wouldn’t it shrink? That would make the top bow up, wouldn’t it?

Anyway, as I said, the table is now cut apart, I’m adding another 6-inch board to replace the 3 inches cut off both sides. I’ll strip the whole top mark it all up to a good experience.

Sure appreciate this forum. I have not answered all your helpful questions, so if you are still wanting to ask something, I will reply. —Pete

[MichaelMouse]

I've never trusted (young 2 year old) air dried, wide lumber for any furniture applications.
Now if it was 20 years air dried, probably.

Read and learn. https://www.fpl.fs.fed.us/documnts/fplgt...gtr113.htm  Chapter 3.

[Stwood_]

Read and learn. https://www.fpl.fs.fed.us/documnts/fplgt...gtr113.htm  Chapter 3.

Whats your point

[titanxt]

Looking at how it is bowed, it appears as if the end of the table closet to the fireplace/heater is the offending end. Look at the line from the end of the table closest in the picture on the left. See how the line of the table top seems to run pretty straight up until it gets to the far end. With the far end cupped upward, the only two points for the level to touch is the two edges. I would seriously doubt that the center cupped as opposed to the end that is near such a dry source of heat.

[Stwood_]

Looking at how it is bowed, it appears as if the end of the table closet to the fireplace/heater is the offending end. Look at the line from the end of the table closest in the picture on the left. See how the line of the table top seems to run pretty straight up until it gets to the far end. With the far end cupped upward, the only two points for the level to touch is the two edges. I would seriously doubt that the center cupped as opposed to the end that is near such a dry source of heat.

He said that wall heater was not in operation/being used.

[titanxt]

Being that it was a customer, are we sure about that?

[MichaelMouse]

Whats your point

Years is immaterial.  Had you read it, you'd know the point.  Equilibrium with environment is a good as it gets, no matter how long.

That's why everyone keeps talking about the CURRENT environment in trying to find an answer.