Warped!

[GreyDawg]

Hi all --

First, mea cupla: I am way behind in posting about my build. Apologies -- description and photos will come. But now I've got a problem...


I swiped LenS' idea for a kitchen box accessible from the side door, as I will be doing all my cooking outdoors:



(Sadly, my carpentry skills are not nearly on par with his ). The box consists of a frame made with 1x2's, skinned with 1/4" plywood. The drop front work area is edge-glued 1x4 pine. For the top, I decided that I need something that could be both a work surface, and on cold or rainy days, a place I could safely use a 1-burner stove for making coffee, etc. inside the van.

My choice was to use an IKEA Lamplig cutting board, which is edge-glued solid beech, and finish it with mineral oil. It's held to the box with four angle irons. Nice, eh?



Well, since it was installed in late November, the van has been in some temp extremes (single digits parked for several days in PA, and in TX up into the 90s inside the van when parked closed up on a sunny winter day). And here's the problem:



It's warped. I first noticed the warp -- not this pronounced -- in frigid PA. This photo was taken in TX yesterday, after the van had been sitting in sunshine for a few days with temps in the 70s.

I'm not a happy camper, and so now the questions are:

• Why was a beech cutting board a poor choice for the top? and[/*:m:b1o7sge5]
• What should I replace it with?[/*:m:b1o7sge5]

I've just yesterday partially installed the desk, which has a top made of edge-glued alder, with a stain/polyurethane finish:



so this hasn't been through any freeze/thaw/bake cycles yet! I have a piece of the alder leftover -- would that be a good choice for a replacement kitchen top? Or can you suggest something else?

Thanks!

[BroncoHauler]

If you happen to know someone who's having a home kitchen remodel done, ask what sort of countertop material they're getting. If they're getting a manmade countertop material (Corian, Silestone,...), the countertop material that is cutout for the sink would be a great tabletop.


Herb

[Skywagon]

Grey Dawg

If you make another cutting board top, try this: When you attach the top to the angle irons, cut slots in the metal so the screws can move in the slots across the grain. Don't tighten the screws so much that the board can't expand and contract across the grain. Next, whatever you finish the top with, make sure that you do the same to the underside. (Equalize the moisture absorption). And finally try to keep it out of the sun.

Hope this helps-
Bill
P.S. It'll probably still warp, but at least you'll know you did what you could to mitigate the problem.

[WVvan]

Excellent advice skywagon!

[GreyDawg]

Thanks, Skywagon!

I have a couple of follow-up questions --

1) how do I cut slots in the angle irons? (I already had this idea, but don't know how to execute it).

2) for the desktop, I sealed both sides with a stain/ polyurethane mix ("Polyshades") but did 5 coats on the top and only three on the bottom. I assume that won't be an issue, right?

I attached the desktop to the pedestals with the same sort of angle iron setup. I guess I need to figure out how to slot those angle irons too. Or are pre-slotted angle irons made? I've seen lengths of slotted material, but it looks too hefty to cut with a hacksaw.


Herb -- would Corian have the same tendency to warp as wood? (Alas, I don't know anyone who is having a kitchen remodel. Are Corian cutouts sold at retail, perhaps at lumberyards (as opposed to HD and Lowes?)

Thanks,

Meredydd

[BroncoHauler]

Corian or similar products don't warp, and don't scorch if you set a hot pot on it. It can show knife marks, but less than a wood cutting board.

Call around to kitchen remodelers. I think they generally throw away the sink cutouts. I don't know what it takes to "work" the material, but I think it's just standard power tools.


Herb

[GreyDawg]

Here's a thought: instead of trying to cut slots in the angle irons, could I find angle irons with large holes, and use a much smaller diameter screw, with something like a fender washer to make up the difference between the screw head size and the angle iron hole side?

Then, if the angle iron is only lightly screwed down, there would be play in 360*, right?

So now the question is whether I can find 1.5" or 2" angle irons with sufficiently large holes, or whether my drill, with a metal bit, can be used to bore larger holes in standard angle irons...

I should probably do this for the desktop; sounds like Corian might be ideal for the cookbox top.

Herb -- I'll start working the phones for Corian!

[Skywagon]

Grey Dawg-

Just take a rattail file and elongate the holes a little, or do as you said. The idea is just to allow the top to move with changes in moisture content, generally due to humidity.
5 coats and 3 coats should be fine, but I find that ideally the two surfaces should be treated the same.
Aluminum angle (Orchard Supply, Home Depot, etc.) is easier to work, as you can use common woodworking tools; (saws, drills, routers, files, sanders, etc.) to work it.
Corian is the same, I believe.
While Corian and similar materials won't warp per-se, if you confine their expansion, they will bow or "warp temporarily" when they get hot. (Sitting in the sun). I wouldn't concern myself with that material like I would with wood.
Plywood, because of the alternating grain directions doesn't suffer from warping to the extent of solid wood.

Bill

[Scalf77]

you might try something like StarBoard instead of Corian. The last I looked it was rather difficult to purchase Corian in decent sizes unless you were an official installer. Both are workable with woodworking tools.