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3/8 bendable ply for interior roof?

Posted:
Tue May 10, 2005 8:59 am
by IraRat
Found a local specialty lumber supplier (anything in Florida that isn't Home Depot or Lowes is a specialty), and their specialty is NOT carrying anything under 1/4.
They have something called bendable plywood, and the guy says it bends like beyond believe without cracking. What do you think about this thickness for a Cubby for the cabin roof?
I couldn't inspect a sheet (it was stocked way up high), so I'm also concerned about the finish for later staining, but that's another issue.

Posted:
Tue May 10, 2005 5:51 pm
by Ross Wade
IraRat,
I use bendable plywood on some of my furniture. It is amazing stuff, but it does crack and split at the edges if you are going for a tight radius

. I personally think that 3/8" ply would be too thick as well as heavy. 1/8" is generally used for the ceiling. However, if you can get it at a great price, I say go for it

.
Just make sure that it bends correctly. You should be able to roll the sheet of ply the total 8' length, ending up with a tube about 20" X 4'

.
Hope this helps,
Ross

Posted:
Tue May 10, 2005 5:56 pm
by toypusher
IraRat,
You might want to use the phonebook and call every place in it that says it sells (or you even think might sell) wood and ask about the 1/8". I could not find it, so I started calling around and found a small mom & pop outfit that has it and will order it if it is not in stock. Beat part is that they will deliver to my house for free! Might want to try other places that are within a 1/2 hour or so drive.
Just my opinion!
Kerry

Posted:
Tue May 10, 2005 8:20 pm
by Finntec
I too went to a specialty lumber supplier and got 3/8" bendable plywood. When I got it home and put it on the roof I found that it easily conformed to my roof, but it was extremely delicate. I was scared. I also thought it would raise the roof so high that the roof molding wouldnt cover the sides. I returned the wood the next day and purchased 3ply 1/8" bendable birch. $33.00 I really like the stuff. It is very strong for the thickness. I have cut it on a table saw for my interior ceiling with out much trouble. It takes a couple of people to hold it because it is so flexible. So far I have fit it to the interior and started to glue it to the first two rafters. When we bent it to the interior curve of the roof, we were a little too agressive and it cracked about 8 " where one of the voids were. I did find some voids in it when I held it up to the light. You can see through it (almost) on a sunny day. I think if we were a little more (slower to bend it) careful it wouldnt have happened. Good luck.

Posted:
Tue May 10, 2005 9:36 pm
by IraRat
Thanks, guys. I found a place to get 1/8 luan, and since I've heard so much talk about that there, I think I'm gonna go for it.
The 3/8 bendable ply does indeed roll up into a tube! (It's that flexible.) It's just that I don't that kind of thickness, or the weight!. However, the thickness won't affect the roof skin, as mentioned above, because this is for the interior roof, which goes under the spars.

Posted:
Wed May 11, 2005 6:01 am
by Endo
Here is my version of bendable plywood. This is the standard Lowe's stuff (1/8 birch) with lots of kerf cuts! It did take alittle time but it bent around the radius without any problem! I used my circular saw and a straight edge to make the cuts (72!). In the first picture you can also see the temporary plywood supports I used to hold the skin in place while the glue dried.


Posted:
Wed May 11, 2005 8:12 am
by IraRat
WOW!
You did a great job keeping those cuts parallel and evenly spaced!
Did you do that for EFFECT? (I thought the 1/8 birch would bend anyway.) Or did you varnish it before attaching and then realize it wouldn't bend after the varnish dried!?

Posted:
Wed May 11, 2005 8:18 am
by Endo
I did stain, seal and put on 3 coats of poly prior to installing. I kerf cut it to make installation easier. I read in another post that some guys cracked 2-3 sheets prior to getting one to make the radius. I just wanted to make sure it worked on the first try!


Posted:
Wed May 11, 2005 11:25 am
by An Ol Timer
If the birch plywood was 1/8" how deep were the kerfs cut?

Posted:
Wed May 11, 2005 2:06 pm
by IraRat
Hey, now that I looked at the photos again, I'm curious about something else:
Is this the exterior roof? Why do I see the spars sitting on top of it?

Posted:
Wed May 11, 2005 2:39 pm
by Ross Wade
IraRat, it looks as though he installed the ceiling panel first. Once the glue is set, he will probably start to lay out the wiring, insulate and then install the outer skin.
It is easier to run all of your wiring and insulate, once the ceiling is in place

.
Ross

Posted:
Wed May 11, 2005 3:28 pm
by asianflava
Endo wrote:Here is my version of bendable plywood. This is the standard Lowe's stuff (1/8 birch) with lots of kerf cuts!
Wow, that looks good. You definitely have more patience than I do.
I never found any 1/8in at Lowes or Depot, only 1/4in. I did buy some 1/8 from a lumber specalty store, I'm able to bend it with no problems.

Posted:
Wed May 11, 2005 7:07 pm
by Endo
I guess it's not really 1/8 the actual measurement is more like 3/16. The kerf cuts are about half the thickness of the plywood. Yes this is the inner skin. After this was installed I placed one layer of 1/2 inch insulation then I ran my wires. Then I installed another layer of 1/2 inch insulation around the wires and a final layer of 1/2 inch over the wires. It sounds like alot of work but it was actually very easy. So I have a total of 1 1/2 inches of insulation in the roof. I will then glue on the exterior skin. You can see more photos here:
http://pg.photos.yahoo.com/ph/tydeanmot ... fa&.src=ph

Posted:
Wed May 11, 2005 10:01 pm
by IraRat
Got you. I was confused because at first I was surprised why it was STAINED, but since you're staining the other, visible side, why the heck not do both sides??

Posted:
Fri May 13, 2005 5:50 am
by Endo
IraRat
Only the inside (visible side) is stained. The photo of the outside does look dark but I think the kerf cuts just reveal the lighter colored core.