Bending 1/8" plywood for interior ceiling?

[belay70]

First time I tried this, it began to crack in places, although it never quite broke. Second time, new trailer. I considered buying 1/8 birch plywood but comparing it at the store, it didn't seem to want to bend much at all compared to the regular stuff. Any tips for getting it to bend to a 19" radius without cracking?

[citylights]

First time I tried this, it began to crack in places, although it never quite broke. Second time, new trailer. I considered buying 1/8 birch plywood but comparing it at the store, it didn't seem to want to bend much at all compared to the regular stuff. Any tips for getting it to bend to a 19" radius without cracking?

Get laun, it is plywood with all the grain in one direction making it easier to bend. Then, I also had to wet mine down with wet towels and go slow with the bending. "Go Slow" depends on your wood. Could be several hours or several days. I have no patience, so mine was several hours, but I broke a couple pieces and had to start over.

Prebend the wood, then after it takes the shape, take it off, apply glue, and clamp or strap it down again until the glue sets. Here is some pictures bending laun to my hatch.







And a broken one on the same 19-inch radius you are working on!



Oh, and I pre bent my interior headliner piece strapped on the outside as a form just to make it easier when I put it on the inside.

[aggie79]

I would suggest either baltic or russian birch plywood in 3mm (~1/8") thickness. This is not the same "birch" you can get a most big box lumberyards.

I had no trouble bending it to a 10" radius at the lower end of my hatch.



I also bent it around the 6" radius at the lower front of my teardrop.



The 6" radius was a bit of a struggle, but I didn't pre-bend it or use hot water.

Take care,
Tom

[Gage]

Some people just don't listen. I used 1/8" birch throughout my tear and had no problem. I also didn't use any water. Didn't want to stain it. Also didn't buy it from a Big Box store. They only sale junk, that's why it's so cheap. Also if you’re trying to roll it length wise, it'll crack every time no mater what uou use. Roll it width wise along the grain.



Sorry if I offended you.

[belay70]

So, is using water a method that works? Is it worth the time and trouble, rather than just trying to bend it dry? I would think adding water to plywood 1/8" would just make it swell and de-laminate?

[woodywrkng]

The 1/8 inch (more or less) baltic birch plywood will bend very nicely, with the grain running properly, as Gage mentioned above, without water. I don't know if the big box stores carry it. Mine came from a woodworking store. Folks say Luan works too, although it's not as nice looking as the baltic birch. If it's really giving you a hard time for some reason, I suppose a few hot and damp towels on the convex side would help without making water marks in the inside.

[citylights]

So, is using water a method that works? Is it worth the time and trouble, rather than just trying to bend it dry? I would think adding water to plywood 1/8" would just make it swell and de-laminate?

If you get wood with high moisture content to start with, you can bend it without adding water as others have mentioned. In Las Vegas where I live, humidity runs about 5% and that sucks everything dry as a bone. "Wet" wood is just not available.

I suppose, If you bend it very slow (over days or weeks) you can bend even dry wood without water. Yea... Good luck with that!

If you do use water, I would not apply it directly to the wood, instead apply a damp towel. Re apply water to the towl as needed. My towels went from soaked to dry in just a couple of hours. Some soaked into the wood, the rest evaporated. For mine, the wood did not swell and I did not get water marks. Even at that, I was not concerned about water marks because I used cheap wood for everything intending to paint or cover with aluminum. The wet towels just upped the moisture content of the wood until it would bend.

Others have reported using steam and heat from a clothing iron, but I have no experience with that.

[grantstew8]

Grain direction is critical.

http://youtu.be/zDw12lsKeWo is against the grain and it was tough to bend and I've a few cracks


Show the ceiling going in bending it withe the grain going side to side. It was really easy. http://youtu.be/Dl9gaIsg6eg

[halfdome, Danny]

I bend 1/8" Baltic Birch plywood for my 6" roll pans.
At that radius it will crack if there's a boat/football patch in that area of the sheet.
For tight bends, select your sheets accordingly .
There is no need to add any moisture to any wood or plywood unless your steam bending solid wood.
Danny

[48Rob]

As stated; quality 1/8 plywood will bend easily.

Luan is a type of ply-wood that is made differently from the typical plywood we think of.

Regular plywood is made of multiple layers of alternating thin sheets of wood (veneer).
These layers are glued under great pressure to form a flexible, yet very strong "board".

Luan plywood is typically used indoors, as an inexpensive "smooth" layer on older less perfect floors as a base for carpet, tile, etc.
It is made with a base core of wood that has little strength, and has a thin sheet of inexpensive veneer glued to each side.

Luan is prone to cracking and breaking when bent or stressed, as it is not as strong as regular plywood and is prone to de-lamination.
Regular plywood can more easily withstand these stresses as it has between 3-15 alternating layers.
Luan has just a cheap fiber core (that isn't designed to bend) with very thin veneer on each side that must resist these stresses.


Rob

[belay70]

OK, I guess its clear I need to make a run to the specialty lumber yard. I hope this baltic birch isnt too expensive....

[citylights]

Show the ceiling going in bending it withe the grain going side to side. It was really easy. http://youtu.be/Dl9gaIsg6eg

That video is hilarious! The plywood is bending like a wet noodle. I have never seen plywood bend like that. I struggled to bend mine... but I guess I got it done.

[Gage]

That video is hilarious! The plywood is bending like a wet noodle. I have never seen plywood bend like that. I struggled to bend mine... but I guess I got it done.

And you probably got your ply at a BIG BOX store which only sale China junk. And by the way I too live in the High Desert with low humidity. So you really don't know what your talking about. I only use quality plywood. It cost a little more but well worth it. How does thaat saying go? You get what you pay for.

[citylights]

That video is hilarious! The plywood is bending like a wet noodle. I have never seen plywood bend like that. I struggled to bend mine... but I guess I got it done.

And you probably got your ply at a BIG BOX store which only sale China junk. And by the way I too live in the High Desert with low humidity. So you really don't know what your talking about. I only use quality plywood. It cost a little more but well worth it. How does thaat saying go? You get what you pay for.

Dude, you are funny. China does not export wood to the US. That is just about one of the only domestic products that we have left. Cheers!

[halfdome, Danny]

Dude, you are funny. China does not export wood to the US. That is just about one of the only domestic products that we have left. Cheers!

I'm sorry to inform you but yes China does import plywood to the US.
I have retuned some 3/4" sheets my customer supplied because of delamination in the center of the sheet.
Total garbage.
Danny