What do you think?

[FestitaMakool]

I got these glued up counter tops in oak, 2000x800x26mm for $30 each.. (The lady at the counter said: That was $435 off for 4 tops.. [big grin]) - See photos below.

Anyway, the price was very right, I figured this can all be used, even if I end up ripping it down and glueing again to a good few projects. But now I’m trying to climate them to get rid of most of the curve..

I didn’t see that in the shop, but look at the end grain, there are two layers, one layer substantially thinner. I figured this is what make up the tension and uneven swelling/drying.
What do you think about it?

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[ChuckM]

You can't go wrong with that kind of price tag, even though they look like to be boards of various sizes glued together. I'd try to rip them apart and glue them to flatten them if acclimatization doesn't work.

One of them for a bench top for the shop, if you don't have a workbench?

 

[FestitaMakool]

Good idea ChuckS, it’d make a very nice worktop.

I cannot make a workbench yet I’m afraid, not one that I cannot easily move through a door anyway. I’d love to have a hefty Sjöbergs style bench, I nearly got one for $200 - and this was one with a good chunky tail vice and a cabinet below even. But it slipped under my nose.
I’d like better to build my own, incorporating experience from MFT use and so on. It would suit me much better. Still, a hefty Sjöbergs bench is nice though - and the labour is happening on top of it instead  [smile]

 

[Crazyraceguy]

I would say that the multiple layer thing is definitely the problem, especially if they were glued up with the layers of equal thickness. Then when planed/sanded to thickness, only or mostly on one side, the tension started.

Maybe they were removed from whatever press was used for the glue-up too soon? or the thick side was much drier than the thinner side? Then it absorbed enough moisture to swell that much?
Certainly it is the same species of wood on both sides?

If nothing else, they can be ripped into narrow strips and glued up into thick pieces that could be used for workbench legs.

 

[Cheese]

The multi layer is the problem, you’ll notice that they all cup towards the thinner layer. That’s confusing for me because I’d have thought they would have cupped towards the thicker layer.. what do I know.  [tongue]

 

[Crazyraceguy]

The multi layer is the problem, you’ll notice that they all cup towards the thinner layer. That’s confusing for me because I’d have thought they would have cupped towards the thicker layer.. what do I know.  [tongue]

It is possible for it to go either way. It just depends on "why". Even something as thin as countertop laminate can cup a sheet of 3/4" thick MDF or Particle board. The "wood" product swells/shrinks and the laminate will not. Because of the way it is cooked/pressed/dried, those sheet goods are far more likely to absorb moisture than release it, but it depends on where it was stored before use and where it is going after. This is why it is recommended that you always balance the panel by applying "something" to the other side as quickly as possible. I have seen long countertops, with a second layer of 3/4" material glued onto the edges as buildup, curl up by a few inches, overnight.
Normally, when screwed down to the cabinets, in an air-conditioned space, they relax and everything is fine. It just looks a little crazy until then.

If these panels were sitting in some home center "relatively" not weather stable, the thicker side of wood on one side of the glue-line has more volume of wood to overpower the thin side.
Heck, you might get them home, let them sit a while indoors, and they will straighten out on their own. Probably not perfect, but better.

 

[jeffinsgf]

Bottom line, there's a reason plywood always has an uneven number of layers.

Grain running same direction, seams almost, but not quite lined up, layers of different thickness and two layers instead of three. They never had a chance.

Also just noticed at least the thin layer is made up of short sections.

I would cut it up, turn it on edge and glue it back together and make a benchtop out of it. Or, plane off the thin layer and use the thick layer only.

 

[Cheese]

It is possible for it to go either way. It just depends on "why".

Ya, those residual skin stress issues, be they in plastics or in wood are a real head scratcher and they always have been. The normal situation is to build a computer model of the structure and evaluate it 3 ways from Sunday, however, that usually doesn't completely solve the issue. There are always issues that don't follow the norm.

Over the last 40 years I've worked with Teflon in both the compression molded form (PTFE) and in the injection molded form (PFA) or (FEP).  Common sense would say that because of the methods that are used to form these Teflon bars, the resin has been uniformly heated, uniformly cooled and thus to some degree stress relieved.

However, when milling those Teflon bars you cannot machine more than .090" from one side before you need to flip it over and then remove the same amount of material from the other side. If you don't follow that procedure the part will potato chip on you. Don't know why but that may also be the case with certain species of wood.

My thought was that those Festita boards were exposed to moisture and after drying the thicker sections of the board dried and they should shrink more because of their thickness, therefore pulling the thinner structure around the thicker structure...that was not the case...therefore I'm confused.

 

[Mini Me]

I would try and wet down the concave face and put that side down on the floor and see what happens. It will most probably bend again though because the thin layer dries out quicker than the thick layer. I have used the wet down technique a lot and sometimes you can just about see it start to flatten as soon as it is laid on the floor.

 

[FestitaMakool]

Seems we’re on par here, although I didn’t get Cheese’s reasonings at first. The different thickness is the obvious culprit here. I have never seen countertops with double layer as here with different thickness. The thicker wood will swell more, so it seems reasonable that it expands a bit more.

Right; it’s made up by short pieces, both layers. This is common here, just like parquet, but hat has plywood under.. Usually these are very stable: using one layer that is.

I’ll try drying it inside, it’s now been a couple of days under roof outside, not very moist weather, but slightly moist in the morning. Table legs is an option that I thought of too.

Mini Me - I thought about the same, I’ve done it with slight success before. However, treating one side (the thin layer) with some sort of clear finish oil to soak in applying wet in wet with slow drying oil is also something I’ll try. I’ll check in with the paint store..

A thicknesser is on my bucket list too  [big grin]. If I go ripping it down, I might as well resaw some on my band saw. Then I could use it on plywood too. I don’t know how it will react to this though.

It’s high rated firewood too!  [big grin] [tongue] - But, nonetheless I think it’ll be useful to anything else than that.

 

[ChuckM]

If I had these boards and wanted to flatten them, I'd first rip each of them into about five 6" wide boards. Once ripped, the cup on each board would be minimal.

After a few weeks in the shop, I'd run each board through the thickness planer to get rid of the cup, hopefully down to 3/4" x 6" boards.

After acclimatization, I'd glue them back using dominoes. Then use the glued up board(s) right away.

 

[Packard]

There appears to be a label attached.  Who is the manufacturer?  Do they have a website?  Do they specify the tops?  Do they offer any suggestions?