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I need plywood bending advice

PostPosted: Tue Aug 18, 2009 4:38 pm
by atkryder
This weekend i bought some 5.2mm birch plywood from lowes which is approx 3/16in. The plan was to line the interior roof with it and stain it. After breaking two pieces of it trying to bend it around my cub profile I really need some advice!! I have read that 1/8 birch will bend but not this stuff!

Seth

bending plywood

PostPosted: Tue Aug 18, 2009 6:21 pm
by norm's tear drop
you can soak it in water some how by making your own kiddie pool useing plastic or use wet towels on it or you use rachett straps on it to start your bend while putting wet towells on it and maybe let sit a day or so and rachett a little each day and then you have a peice that atleast is going and started in the direction your going also you can slice the back side of plywood with a razor knife or maybe you could CAREFULLY put saw kerf in it with skill saw or you could use al these ideas in some sort together in all cases just go slow


norm

PostPosted: Tue Aug 18, 2009 6:44 pm
by mikeschn
We've been there. We broke some of the thicker stuff trying to line the inside of the tiny Benroy.

My suggestion is to save that plywood for doors and drawers, and get some thinner stuff for lining the ceiling. Try to find some 1/8" birch plywood. That usually bends really nice and easy.

Hint: you might try rotating the plywood 90 degrees... it bends easier that way!

Mike...

PostPosted: Tue Aug 18, 2009 7:06 pm
by atkryder
Thanks for the info.

Mike
The problem with rotating the plywood is my camper is 5ft wide.

PostPosted: Tue Aug 18, 2009 7:10 pm
by mikeschn
atkryder wrote:Thanks for the info.

Mike
The problem with rotating the plywood is my camper is 5ft wide.


That works out in your favor! Bending the plywood along the width is easier that bending it down it's length.

Still, I would start with 1/8" birch!

Mike...

PostPosted: Tue Aug 18, 2009 7:48 pm
by kennyrayandersen
I agree with Mike. The 1/8 inch on the roof will also get some extra strength and stiffness from the curvature (curved panels are stronger than flat panels); but, if you HAD to use it I would scarf one side. The commercial products scarf every inch or so, you could do it a bit less, but I would do it at least every 1-1.25 inches :thinking:

PostPosted: Tue Aug 18, 2009 7:52 pm
by Senior Ninja
I bent the front panel of my tear by fastening it at the top where it would just curve over the front and be long enough to fasten to the floor. I placed a large beach towel over the outside of the bend and poured an entire tea kettle of boiling water slowly over the towel. I also used a spray bottle to wet the inside of the curve. I applied a little weight to the front edge and went back in the house. An hour or so later I returned an found the plywood bent almost completely to the curve I wanted. Just a little push allowed me to fasten the plywood in place permanently.
I also bent trim pieces in the shower by jamming them into the curve I wanted and allowed the shower to keep them wet until the were curved.
Hope this helps.\
Steve

8)

PostPosted: Tue Aug 18, 2009 9:34 pm
by TPMcGinty
I used bending plywood. It worked great!

PostPosted: Wed Aug 19, 2009 10:18 am
by green_eyed_diablito
i broke a few pieces of ply too. i finally found success with 1/8" bendable poplar ply. you could just about bend this ply into a roll.

PostPosted: Wed Aug 19, 2009 2:02 pm
by Kevin & Sandy
The interior pieces of plywood for my camper kinda creaked and cracked when bending, so I held it in place (almost in place, not the tight radius it needed to be in) for a few days with a tiedown strap to "train" it to bend. I "think" it helped a little because it went into the final position without further damage !!!
In the couple days the weather got much hotter and humid, that prolly helped as much as anything, seeing how I didn't soak it or give it relief cuts.

PostPosted: Thu Aug 20, 2009 11:17 am
by alffink
Seth

Now mine is 4' wide so I had the grain running the leagnth of the tear
Kinda shoved the 1/8" red oak panel into the corner formed by the forward lower cross beam and the floor, made up a couple of T-braces similar to what would be used when sheetrock'n a cieling, reversed a couple of bar clamps and slowly jacked the baces against the paneling, made sure to maintain contact in that forward corner and I just kept jacking slowly alternating between forward and aft and it just formed into the cross beams, took a couple of tries to get the T-braces into the correct locations, but it went smoothly with no cracks or breaks in the panel.

I think there is a picture in my album showing the T-braces in use, I'll check that after I post this and add the photo if I need to, from my complete build collection.