Laminate countertops

I'm making a sewing table for my wife for our hobby room. After a kitchen remodel, the old base cabinets went in there, along with a custom built cabinet/closet folding table. Both of the previous additions received 6' laminate countertops, complete with backsplash. The remaining available wall has about 5' of space, and it's got a window on it (with a standard 34" sill). she wanted a sewing table with a countertop to match the others, except the top must slide under the window sill.
I figured it should be too hard. I built the frame out of 3/4 MDF. I took the skill saw and lopped off a good chunk of the backsplash, figuring to delaminate and fold down enough to make a flat surface. The delamination didn't go as easy as planned, and I wound up chiseling away the particle board to leave just the laminate, I figured I could just heat it up and bend it down. It was too hard to heat it evenly enough, and I broke the hell out of it.
Moving to option 3, I put the countertop on the table saw and took evened what was left of the edge, planning on filling the void with 3/4 MDF, which will blend satisfactory enough with her travertine-like laminate.
She wanted 3 drawers, and since I had 1 12' and 2 18" salvage drawers, I made her 3 12's. It was fun, trying to determine placement of the new slides, since the 1 vertical was not in place, and after it WAS installed I figured I wouldn't have much room to get in there with the power driver for mounting. After several hours of measuring and remeasuring, and finally mounting, I had the slides on the drawers, slides on the side of the cabinet, and slides on the yet-to-be- installed vertical piece. On paper, it was perfect!
I set the vertical piece in place (the countertop was already mounted), put the drawers in, and it looked like hell! Everything was crooked! I verified the sides were square and noticed the side of the cabinet was off the floor. Putting a level in a drawer verified one side was high.
I figured I overlooked cutting the vertical piece to height, which would explain everything, so I figured it was an easy chore of pulling it out, cutting it in the table saw and cutting it ti length. I put a tape on it and it came out dead on. As I was sitting there scratching my head I noticed the the countertop had a dip in the middle. Sheesh!
I put it all back together, sat on the countertop, and everything was perfect. I got up, the top returned to it's skewed condition, and everything was off again.
Now I'm unsure of what to do next.I could replace the countertop, but I don't want to spend another $40 if there's another way. I could shorten the vertical and remount the slides on it,which would make the drawers right but the top will be uneven.
All this work so far has been in the shop, and the outside doors have been open most of the time.
Did the removal of the backsplash allow the top to deform? Was it the humidity? Was it the fact that because it wasn't as big as the base it is currently only supported by each end?
If I finish it as planned and place it in her hobby room, will it return to level once it's supported on 3 sides with the center vertical or will it stay this way forever? I'm contemplating placing my lathe on it (with the vertical in place) and see it that makes a difference after a few days.
Anyone else run into this before?
Drifter Bend, Oregon
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A proper laminate top will have a laminate backer on it as well. They seldom do, however. The top was held somewhat straight by the back-splash, but the removal of it, along with it being exposed to air is the likely cause. In a lot of cases, the cabinets will help keep it straight.

Not likely to have a successful ending.

Yup. Make a new top. And if you want the top to float freely, use a balance sheet. (Which, in a pinch, can be normal laminate.)
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Drifter wrote:

Have you considered fastening the top to the vertical sides and partition? Also, the back and face frame if they exist.

Something that is supposed to be flat but isn't? Sure.
--

dadiOH
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