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Forum topic by vmallery posted 04-30-2018 03:58 PM 691 views 0 times favorited 11 replies Add to Favorites Watch
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vmallery

2 posts in 539 days


04-30-2018 03:58 PM

Topic tags/keywords: question

Hi all,

I’m new to woodworking and am looking for a little advice. This is my first project where I’m trying to make a small hallway stand. I used wood glue to glue pieces of pine together for the top and planed/sanded it down. After a couple days, you can see it started to form a cup. I’m wondering what I did wrong? And what could I have done better to make sure the piece remained flat?

Thanks


11 replies so far

View TechTeacher04's profile

TechTeacher04

412 posts in 2044 days


#1 posted 04-30-2018 04:20 PM

Typically pieces like you have would be glued in a different orientation, think about the way a hardwood floor would be layed out. It provides more strength and less chance cupping which you are experiencing now.

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Rich

5001 posts in 1102 days


#2 posted 04-30-2018 04:33 PM

That’s a really unorthodox choice of not only the wood, but (as the previous poster said) the orientation. You’re going to struggle with using construction lumber because it’s not stable. If you want a thick top, get some 8/4 hardwood and glue it up edge to edge (NOT face to face). Maple, cherry, alder, white oak… there are lots of choices. Find a good hardwood dealer too. The big box stores aren’t the place to buy quality hardwood.

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LesB

2206 posts in 3955 days


#3 posted 04-30-2018 04:57 PM

I see a lot of “center” cut pieces of wood (the very center of the log) that probably came from small regrowth trees from a tree plantation. OK for for framing work but not for what you are trying to do. What you need for this type of project is quarter sawn lumber (hard wood would be the best) and even with that if there is a curve to the end grain growth rings you should be careful to alternate the directions of the curve as you assemble the pieces.

There is lots of info on the internet about how logs are sawn so I won’t fill this response with explanations.

The piece you have in the photograph will continue to flex back and forth as the ambient humidity changes…..unless you happen to live in a stabile climate where this doesn’t happen.

Sorry, time to try again but we all have learned a lot from our mistakes.

-- Les B, Oregon

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bbasiaga

1243 posts in 2507 days


#4 posted 04-30-2018 05:17 PM

Next time, cut the pieces a little big and let them sit in your house for a month or two to dry out. They will move less. That one may stabilize in a mo th or two and you could try and reflatten it at that point.

Construction lumber is usually wet, and for furniture needs extra time to acclimate. I made a workbench out of it and have had no problems, but I did let it sit and air out a month after I brought it home and before I milled it.

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

View vmallery's profile

vmallery

2 posts in 539 days


#5 posted 04-30-2018 05:34 PM

This has all been VERY helpful, thank you all much appreciated.

View jerryminer's profile

jerryminer

960 posts in 1954 days


#6 posted 05-01-2018 05:37 AM

I think material selection is your biggest issue. As was said above, many pieces in your top contain the “pith”—the very center of the tree. This is unstable material. Dryness also factors in—your wood was probably not completely acclimated when first flattened.

Face-to-face glue-ups are fine, though, We’ve done a lot of tabletops this way. (And traditional European work benches are done this way, too—and have been for centuries). Dry, stable material is what makes the difference.

-- Jerry, making sawdust professionally since 1976

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JBrow

1368 posts in 1432 days


#7 posted 05-01-2018 11:46 AM

vmallery,

If one face of a panel has more moisture than its opposite face, cupping can result (concave on the drier face). This could happen when a panel that is flat after milling is set on a solid surface, even when the wood was fully acclimated before use. It may return to flat if the panel is elevated off the solid surface so that air can flow freely around all surfaces.

I agree with jerryminer and see nothing wrong with gluing wood face to face. My workbench top was made face-gluing maple. The joints remain tight and the top is flat after 30 years of service.

View Craftsman on the lake's profile (online now)

Craftsman on the lake

3016 posts in 3950 days


#8 posted 05-01-2018 12:05 PM

I’ve made some framing lumber furniture. Lots of fun. Works pretty easily, if you mess up a piece it’s not expensive. And, in the end, if you like that look, it comes out pretty nice.

Two comments. (aside from those already posted)
I’m sure you glued together these short pieces for a reason, but would you consider using fewer, longer pieces and gluing them along the length? It would really diminish/eliminate the cuppoing.

Another thought. Whenever I use framing lumber for this purpose I never buy 2×4’s. Purchase some of the clearest, straightest grained 2×10’s or 12’s that you can find. Slice them up to the widths you want. Then joint and plane them for glue-up. This way you’ll never have a piece with that completely cupped grain in it. Besides, it’s very hard to find 2×4’s that don’t have some bow or twist in them. Large lumber though is much straighter and straighter also when sliced up.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

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TheFridge

10859 posts in 1998 days


#9 posted 05-01-2018 12:30 PM

If you lay it on a flat surface, especially right after gluing up, it’s probably gonna cup.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View bondogaposis's profile

bondogaposis

5542 posts in 2864 days


#10 posted 05-01-2018 01:09 PM

You can still salvage that. First let dry some more, in such a way that air can circulate all around it. Construction lumber is not dried to furniture standards. Then level it and take out the cup and twist using hand planes and winding sticks. Shouldn’t be too difficult with pine. While the top is drying make the base.

-- Bondo Gaposis

View Robert's profile

Robert

3539 posts in 1993 days


#11 posted 05-01-2018 02:49 PM


Next time, cut the pieces a little big and let them sit in your house for a month or two to dry out. They will move less. That one may stabilize in a mo th or two and you could try and reflatten it at that point.

Construction lumber is usually wet, and for furniture needs extra time to acclimate. I made a workbench out of it and have had no problems, but I did let it sit and air out a month after I brought it home and before I milled it.

Brian

- bbasiaga

This ^^ plus what Fridge said too.

-- Everything is a prototype thats why its one of a kind!!

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