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Minimize warp in long narrow door

1849 Views 40 Replies 12 Participants Last post by  je_an

I'm about to build a set of bi-folding closet doors. Each panel will consist of 9" x 80". I'm concerned the panels might warp since they are narrow and long.

I think one post suggested letting the wood dry and plane it on both sides. Unfortunately I do not have access to planer or joiner. :(

Is there somethings I can do to minimize warping with limited tool set? Would using plywood better than wood strips for the frame? The doors will be painted and mounted using bi-fold door hardware.

Rectangle Parallel Font Symmetry Pattern

Thank you so much for your help!

Bi-fold door: This is due to space issue. Large door(s) will collide with the bedroom door. Pocket door is not an option and I don't want barn door or sliding door.
Painted: This is the look I want. I love beautiful wood furnitures, but do not like wood grains on the wall. Sorry, I hope it doesn't offend anyone. :)


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I have never had a residential door I've built warp. The frame and panel construction makes it very stable. Take a look at my projects to see the type of doors I build if you wish.

I will say that the panel layout you're planning is going to make glue up quite a challenge if you don't go about it properly.
Four 9" x 80" panels adds up to 36" by 80". Hardly a custom opening for a door. When I make doors, I allow 1/4", meaning that for a 36" opening, I build a door that's 35 3/4" wide. That's a common figure if you look around. In your case, you'll need to allow some relief between each door unit as well. If you build four 9" units for a 36" door opening, it's not going to work.

I fear you're getting well-intentioned advice, but some that's not based on experience and, in my opinion, flawed. For example, the thin strip reinforcement that's later milled off will serve no purpose other than to complicate the job.

I'm probably wasting my breath, but I'll say it again. I've never had a door warp, but that panel layout you have is going to give you headaches during assembly. I also think your proportions are off on the rails.

If you're going to build that door, I strongly recommend building it as one piece and ripping the four units apart after it's constructed. If you build them individually, you'll have problems getting it all to line up.

I constructed this door as a single unit and ripped it in half. It fits in a 24" wide linen closet opening.

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Laminated wood is MUCH stronger and MUCH less likely to warp than a single solid piece of wood.

- Oughtsix
That statement doesn't match my experience. I could go on about other claims as well. Do you really believe two 3/8" pieces of pine glued face-to-face is stronger than a single board? I strongly suggest you try it. I know what will likely happen, but you'll get a good lesson from doing it.

Just out of curiosity, how many residential doors, bi-fold or otherwise, have you built? Post some photos if you have them.
Interesting Rich, I would lay all the styles side by side and used knife nicks to align all rails. Never dawned on me to make as one and rip it. Nice door, what are those panels on top made out of?

- controlfreak
Those are juniper latillas we picked up on a trip to Santa Fe. We wanted to match the vanity in the room.

My wife does that part. There's no way I have the patience to cut and fit all of that.
Just for fun, I went looking for some numbers. As it turns out the data refutes the statement that "Laminated wood is MUCH stronger" than a single solid piece of wood.

I found this PDF from the USDA Forest Service web site. Here is a quick screen grab from it:

Font Number Parallel Pattern Monochrome

You can see that plywood has a lower MOE an MOR than any of the woods. Moreover, they aren't even listing woods with the highest values. For example bloodwood has a MOE of 20.78 GPa and a MOR of 174.4 MPa.


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I glue up laminations all the time and yes they are definitely much stronger than single pieces of wood.

- Oughtsix
So the US Forestry Service is wrong?
So the US Forestry Service is wrong?

- Rich

Sorry Rich, you aren t worth my time to have a fight with. LOL!

- Oughtsix
You can't refute the US Forestry Service, and instead choose to insult me? I get the picture.

This matter is settled.
Rich - plywood isn t the same thing as the laminated boards that Oughtsix is talking about.

- northwoodsman
Here's a quote from him in post #19, second paragraph: "Plywood is laminated wood hence its strength and dimensional stability."

I'm satisfied with the data in the Forest Service document I linked to, so until someone posts data to the contrary, I'm sticking with it.

And, sadly, you chose to go here:

Why do you feel that you have to argue with almost everyone on almost every subject?
Why do you feel it was necessary to butt in? Did I tell anyone they weren't "worth" my time? I cleared up some misinformation and was insulted for my effort. I think you're barking up the wrong tree.
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