glued up panel warped

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Forum topic by dbw posted 01-08-2018 01:07 PM 4939 views 0 times favorited 76 replies Add to Favorites Watch
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414 posts in 2412 days

01-08-2018 01:07 PM

Topic tags/keywords: warping moisture panel glue-up

Hello all. I need your help in figuring out why this panel warped. It is part of a trash can lid. I made a trash can for my daughter. Her boyfriend took it home for her. He left it in the bed of his pickup truck overnight. The next morning he brought it into her house and the lid was warped significantly. Here are the particulars: the panel is made of 2 pieces of beech wood which I edge glued without any mechanical support. Just TB II glue. The finish is water based stain and Gloss MinWax Polycrilic. Is this piece salvageable or do I need to make another one? Will the moisture in the trash cause any panel to warp?

-- measure 3 times, cut once

76 replies so far

View LittleShaver's profile


676 posts in 1395 days

#1 posted 01-08-2018 01:50 PM

I would let it settle out in the space for a few days before I worried about it. I’m not sure where you are but I had a recent experience moving something from a moist environment to a dry environment. Warp self corrected after a few days.

A finish slows the rate of moisture absorption, but it will still happen. Perhaps introducing a gap between the bin and lid will allow moisture to escape?

-- Sawdust Maker

View Firewood's profile


1221 posts in 2409 days

#2 posted 01-08-2018 01:55 PM

My guess is moisture settled on the panel overnight causing the exposed surface to swell. Leave it sit inside for a few days until it finds its equilibrium. Lay it flat bowed side up but raise it so both top and bottom are exposed to the air. See how it looks then.

-- Mike - Waukesha, WI

View Lazyman's profile


5436 posts in 2163 days

#3 posted 01-08-2018 02:07 PM

What kind of wood is it? If it straightens itself out, you might want a couple more coats of poly just to add a little more moisture barrier, if nothing else for cleaning.

If you end up making another, I would consider either using plywood, with edgestrips to hide the plys, or using quarter sawn lumber which has less tendency to warp with moisture changes. If you cannot find QS lumber in the species you want, You may be able to rip the wood you have into strips and reglue them so that the growth rings are perpendicular to the surface. Depending upon the wood you use, you’ll get sort of a butcher block affect that may actually be quite nice looking (just like your workbench top).

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View John Smith's profile

John Smith

2440 posts in 938 days

#4 posted 01-08-2018 02:10 PM

did you alternate the grain pattern ?
if you want to save it, I would cut it into 4 pieces and alternate the grain.


-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View Kazooman's profile


1492 posts in 2728 days

#5 posted 01-08-2018 02:14 PM

Sounds to me that the cure for the future would be a different boyfriend. Not very smart to leave a custom made piece of wooden furniture in the bed of a pickup truck overnight.

View bonesbr549's profile


1588 posts in 3842 days

#6 posted 01-08-2018 04:55 PM

Ok think we all had that happen. A couple options. First wipe the humps side with water and place some big weight on it and leave it a few days. It may just come back had that happen. If that don’t work, rip it and reglue.

Also wondering did you bring the wood into your shop and work with it without letting it rest? That will cause issues too.

Take your stock down after a couple weeks in the shop.

Good luck.

-- Sooner or later Liberals run out of other people's money.

View dbw's profile


414 posts in 2412 days

#7 posted 01-09-2018 01:28 PM

A few points based on your replies:
1) I let the wood rest for a week before I did anything to it.
2) I did not alternate the grain pattern.
3) it appears the heavy weight trick isn’t working. I’m using a box of 12”ceramic floor tile and it may not be enough. My next trick will be to wipe it down with water and find something which will create more pressure than a box of floor tile.
4) My favorite idea is for her to find a replacement boyfriend!!

-- measure 3 times, cut once

View BurlyBob's profile


7619 posts in 3041 days

#8 posted 01-09-2018 04:10 PM

I had the same thing happen with several beech glue ups for a project. I spent several weeks trying to flatten using everything I could think of I ended up putting all those pieces aside and buying a sheet of oak plywood.
What’s a bit odd. I’ve since really started appreciating what a real nice wood beech is to work with. I much prefer it to poplar.

View John Smith's profile

John Smith

2440 posts in 938 days

#9 posted 01-09-2018 04:54 PM

do the math and see what would be the most effective for a long time cure . . . .

wetting and weighing down with bags of sand and ceramic tiles for a month
only to have the same problem reoccur once it re-acclimates later down the road. (and it will).
- vs -
running it through the table saw and cut it into equal pieces, alternate the grain,
glue it back up, and start finishing it the next day.

(run a pencil mark across the top of one end prior to cutting – - – -
so you will know how to assemble it back with alternating grain).

jus my Dos Centavos because I have Been There and Done That !!!! (AND – I got the t-shirt).


-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View Woodknack's profile


13395 posts in 3155 days

#10 posted 01-09-2018 06:47 PM

Alternating the grain is a myth so don’t worry about that. It warped because the boyfriend left it outside laying flat. Wood movement is hydraulic, you’ll have to carefully introduce moisture or remove moisture to make it move again.

-- Rick M,

View John Smith's profile

John Smith

2440 posts in 938 days

#11 posted 01-09-2018 06:49 PM

m y t h ???

I have been gluing up panels of different species of wood for exterior sign panels for over 40 years
and I have come to believe that in alternating the grain to “prevent” cupping, curling and warping works.
myth or not – I strongly support the theory.

this is a good read:

and I have fabricated dozens and dozens of signs for the National Park Service and US Forest Service
out of cedar, cypress and redwood.
they actually have “Government Specifications” on wood sign fabrication and they clearly describe how they
want the panels to have alternating grain, WITH a white oak spline between boards, AND dowel pins.


-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View a1Jim's profile


118066 posts in 4352 days

#12 posted 01-09-2018 07:01 PM

I agree with Rick I use to alternate growth rings up and down the first year of woodworking but after that, I glued table tops and panels for the best grain match and have not had any problems the last 30 years. I was a big Norm fan and still am but this is one area he was wrong.
I would guess this problem had to do with this being left outside and moisture infiltrated the wood. even though it has a finish. Is the end grain finished? try putting a heat lamp over the convex side for a while and keep and eye on it,but not to close, when you do that put some stickers underneath.


View Aj2's profile


3085 posts in 2573 days

#13 posted 01-09-2018 07:25 PM

I would be surprised if that panel didn’t warp. If you made a 100 of them maybe one would behave in service. Beech is very unpredictable

-- Aj

View AlaskaGuy's profile


5804 posts in 3084 days

#14 posted 01-09-2018 07:28 PM

Well, I have to say I’ve been gluing up panels for over 40 years also. Never payed attention to alternating, I always go for the best color and grain match. I also don’t rip wide broads to 3 inches wide and glue them back together.

I will say most of my panels have been more cabinet door size an not as large as John Smiths shows. Still I’ve never had warping problems.

Edit to add: I don’t leave my panels outside overnight laying flat

-- Alaskan's for Global warming!

View bonesbr549's profile


1588 posts in 3842 days

#15 posted 01-09-2018 08:09 PM

I’ve seen conflicting opinions on growth ring alternation for so many years. Some swear by it others don’t. I use to many years ago, but had a panel that I did that with warp just the same, and it was more my fubar, of taking down the rough stock quickly and only off one side that did more damage than anything else.

Generally a cup like that is from releasing too much moister from one side or resawing and exposing that center to air and that surface just dries quicker than the other.

I aclimate the wood to the shop as the OP did, and when milling I take it down in stages and watch it. Stickering between each stage. Had temendous luck only bad one was a door that I used a piece of flat for a stile rather than cut one more wide board to get some QS stuff for. Well that just caused me to not only cut that board but but the other stile and 2 rails. Salvaged the panel. Would have been a lot cheaper in time and materials to have just done it right the first time. Now If that board moves when I first take it down about 25% (and sticker overnight or a 2nd day) it goes in the cutoff bucket for an emergency secondary piece later.

One last thought, I figure my needed lumber and add 25-35 percent extra depending on wood tendency to move and go with it.

Some times better to just chuck it. But I would try the wet side and load it down with weight like cinder blocks or a good heavy tool and leave it for a 3-5 days. You will see pretty quick.

Good luck and cheers!

-- Sooner or later Liberals run out of other people's money.

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