Need Help - Table Leaves Warped While Finishing....

Not sure if this is the right forum or not, but thought I'd start here. My wife was working on rehabbing an old table she picked up dirt cheap. It is solid oak, but the finish was rough. She has the base complete and had started on the top when Snowmageddon/SNOWVID21 hit. At that point she had only put her first coat of stain (water based) on it. When she went back out after we went from 70 degrees to -4 to 81 in the course of 8 days, the leaves had cupped up pretty bad (to the point we couldn't even force the table closed). She sanded the top back down, and it self corrected a little. The pic below is after she sanded it, and we were actually able to somewhat force the table back together with the leaves in, but it is still cupped pretty bad. So, I'm here for advice on if there are any tricks to straightening this back out. I appreciate any help.

Attachment 453348

Was the finish sanded off the bottom? If not, that's most likely what led to the problems. If it was, was it stained at the same time the top was? Both of these lead back to wood moves in response to changes in RH and moisture. In order to keep it in balance you have to treat both sides the same as much as possible and always let air circulate equally around both sides.

John

If the original finish was removed from the top surface of the tabletop only and not the bottom, it's likely that moisture was absorbed from the air more so on the top surface than the bottom . That would expand the top surface of the tabletop and create bulging. Did you indeed mean "cupped".(center down, edges up) Regardless, I would think that if you left the table in a more controlled environment for a while before continuing refinishing, it might straighten out.

Tim

Just see that John beat me to it.
Good luck with your project!

I would find another project for now. Let the table rest a week or two with good even air circulation . I would place it on its end and out of
sunlight. If you don’t see improvement ,give it another rest. If the easy way fails, you can try more water! Put it on the convex side. Yes
that is counterintuitive, but proven by scientists to work... sometimes. The water causes the top to swell and push the fibers together ,so the
table gets worse because the fibers are too tightly packed.....but that causes them to shrink as they dry and pull the top in the right direction.
Sometimes.

In theory, when the humidity goes back to what it was, the moisture content of the wood should go back to what it was, and then the shape of the wood should go back to what it was. It may take some time for the moisture to absorb, but is should get there at some point.

I can relate to the temp swing. We went from around 30F before the polar vortex, to below zero for a week or two maxing out to -28F and then back up to 45F 8 days later. My coworkers from California were having trouble conceptualizing how cold it got here, so I said that one night when I took the dogs out, it was nearly 100 degrees warmer in my house than it was outside.

Quote:

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Originally Posted by John TenEyck

Was the finish sanded off the bottom? If not, that's most likely what led to the problems. If it was, was it stained at the same time the top was? Both of these lead back to wood moves in response to changes in RH and moisture. In order to keep it in balance you have to treat both sides the same as much as possible and always let air circulate equally around both sides.

John

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No, she didn't remove the finish on the bottom, which is why I'm a little confused by the way it warped. It indeed cupped - down in the middle and raised on the edges on the top. I would have thought it would move the opposite way....

Quote:

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Originally Posted by Clark Harbaugh

No, she didn't remove the finish on the bottom, which is why I'm a little confused by the way it warped. It indeed cupped - down in the middle and raised on the edges on the top. I would have thought it would move the opposite way....

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During our cold snap the humidity also dropped dramatically which lowered the moisture content on the surface causing it to cup.

When a finished, stabilized piece of furniture, gets moved to a garage & finish stripped off one side "things" can happen.

If the unfinished top absorbed/lost moisture the wood will swell/shrink that determines which way the cup goes.

Fixing the cup might be as simple as putting a fan blowing across the top or wetting the boards.

You can also bring it in the house and give it some time.

If that doesn't work, I would sand the bottom and wet it, clamp it in some cauls, again keep it in the house.

One trick that works well for something like this is to keep the leaves in plastic bags between sessions.

Very simple fix. If it was flat with finish on both sides, it will go back to flat with the finish off both sides. Sand both sides clean and stack on a flat surface on stickers in the same environment it was when it was flat. Let it sit until it is flat again. Then finish both sides evenly.

Dan

Quote:

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Originally Posted by Andrew Seemann

In theory, when the humidity goes back to what it was, the moisture content of the wood should go back to what it was, and then the shape of the wood should go back to what it was. It may take some time for the moisture to absorb, but is should get there at some point.

I can relate to the temp swing. We went from around 30F before the polar vortex, to below zero for a week or two maxing out to -28F and then back up to 45F 8 days later. My coworkers from California were having trouble conceptualizing how cold it got here, so I said that one night when I took the dogs out, it was nearly 100 degrees warmer in my house than it was outside.

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I took a flight once, and had a 100F temperature difference from getting on to getting off. Pretty hard to decide what to wear. I guess, layers, layers, layers...