Red Oak; Need a Twist

[max_in_graham]

I've been pretty well occupied with hanging gypsum in the studio for the last couple of weeks, but now I'm finally seeing the end of the construction process!! WOOO HOOOO!

I'll soon start the process of planing and jointing about 1400 bd ft of red oak to be installed on the walls and ceiling.

The walls are, thankfully vertical and straight sections... as are most walls.

The ceiling of one room (the tracking room) is quite the opposite. The ceiling is a series of curves that were created by the rafters being set against a microlam beam that rises on one end. It's not a single curve, but a series of curves, because of the room's irregular shape.

The design calls for the red oak to be spaced off the gypsum with furring strips, so I do have something solid to attach to. The problem I'm envisioning, is getting the boards to twist along the run of the boards.

I've not worked extensively with red oak, but I know it's not exactly the most flexible wood to work with. Is there any advice anyone would care to share on how to get the boards to twist into shape?

The boards are supposed to be an alternating pattern of 1x4, 1x6 and 1x8, and spaced a very specific amount of distance between them for acoustic purposes.

Experience has shown me that longer boards are "easier" to twist than short boards... and some of these lengths are going to be under 3 feet long... with some lengths being a full 8 feet.

HELP!?!

 

[Mike Davis]

It would be a lot of extra work but you could resaw the boards about 1/8 inch thick. That will be a lot easier to bend and twist. Then you will have to build up to the required thickness with multiple layers of same size boards. Glue and screw to laminate them back together.

 

[PChristy]

Max - I can't picture what you are asking - is there away you can post a pic or two to show what you have -

 

[walnutjerry]

Max----Red oak has excellent bending properties. Better than yellow pine. Pending the radius you are bending will determine how well you can bend the oak. Also, the more moisture in the oak the easier it bends. If you are using KD oak it will be harder to bend than AD oak. There are several ways to deal with it. Mike had one suggestion that works (the lamination approach). Properly spaced kerfs on the back will do it also. And there is always the option of steaming the oak to make it pliable.

Without seeing the actual enviroment--------I am not sure which way I would go.

Jerry

 

[gator]

Do you really need full thickness boards (3/4" I assume)? Or can you use thinner boards? If you can use the thinner, just resaw to 1/8-1/4" and they will twist without a problem.

George

 

[max_in_graham]

Gentlemen,

Thanks for the responses...

The lumber I have is mostly KD (about 1000 bt ft from the big Raleigh Lumber Run) with the remainder being AD.

I s'pose this is pretty wonked to visualize w/o pix, so here's a few to hopefully clear up this insanity...

There are now two layers of 5/8" FR gypsum over the OSB, so the angles/twist is smoothed out a bit. I don't think the latest pix illustrate what the situation is, as well as the earlier shots do.

The red oak boards are supposed to be parallel to the microlam beam, and cover the entire ceiling.

According to the designer's spec's, the boards are also supposed to be a full 1" thickness. When spaced at specific distances, the combination of all the factors create what is commonly referred to as Helmholtz effect.

(If anyone wants to play with the math.... ) :BangHead:
fo = 2160*sqrt(r/((d*1.2*D)*(r+w)))

r = slot width
d = slat thickness
1.2 = mouth correction
D = cavity depth,
w = slat width
2160 = c/(2*PI) but rounded
c = speed of sound in inch/sec.

While laminating is definitely an option, I'm concerned with how long it might take to do a lot of the ceiling this way. Maybe I'll get lucky, and will only have to laminate a few boards. :dontknow:

I've seen video of steaming, but never tried it. Is a steamer very hard to build? –or– is there a member who might have one, that would be a willing (glutton for punishment) soul to help out?

I've done back-sawing before, but that's been across the grain to deal with a simple curve in one direction. When dealing with twist, how would you cut... down the length of the board?? or would you cut diagonally?

It's really hard to say how much twist I'm going to have to deal with, but from putting up the OSB and the gypsum, I would have to guess that in most places it's maybe 1/2"-3/4" worth of twist from diagonal corners of a 1x8... say... 6-8 ft long. (In trying to put up as large of pieces as I could, some pieces of OSB and gypsum, had about a 2" "twist" across 48" of run.)

There are some pretty sharp angles that I have to deal with, but those will be actual breaks, with two furring strips... one on each side of those angles.

(Told ya this was insanity! :rotflm: )

Thanx!
Max

p.s. Anyone got the reservation number for Dix Hill????????
(I think I may need it before long)

 

[walnutjerry]

Gentlemen,







I've seen video of steaming, but never tried it. Is a steamer very hard to build? –or– is there a member who might have one, that would be a willing (glutton for punishment) soul to help out?

Max----------a steamer can be a simple plywood box since it will probably be a one time process for you. If you want more information send a PM. I have done some steaming but not on KD material. Most of my steaming is for chair parts but should be the same principle for what you are doing.

Jerry

 

[JackLeg]

p.s. Anyone got the reservation number for Dix Hill????????
(I think I may need it before long)

Max: Just show up at their door with a backsaw and a chisel in hand! They've seen this before and will admit you!!

:rotflm::rotflm::rotflm::rotflm:

 

[BobcatBob]

Since you have to fasten the oak to furring strips, is it possible to shim the strips to reduce the twist? Or, is the twist something that was built into the design and has to be. I can't imagine how long it will take to steam and install/twist 1" RO into place. Be sure and post a picture after you got it all figured out and finished the room.

 

[max_in_graham]

Since you have to fasten the oak to furring strips, is it possible to shim the strips to reduce the twist? Or, is the twist something that was built into the design and has to be. I can't imagine how long it will take to steam and install/twist 1" RO into place. Be sure and post a picture after you got it all figured out and finished the room.

I honestly can't say for certain whether the twist was "built-into" the design or not... although I suspect that it probably is assumed that there would be some twist... but how much is really expected, is about anyone's guess.

hmmmm... just had a thought.... (scary as that is, huh?) Maybe I'm asking this the wrong way....

Should I really be asking how much twist should I expect to be able to get out of 1" red oak that is 1x4, 1x6 and 1x8, for distances of say... 4, 6 and 8 feet?

I know darn good and well that I probably won't get much more than 1/16" out of anything much shorter than a 3 foot piece.

Oh yeah... pix...

I've been documenting this whole lurid affair for 5 years. So, yes... there WILL be pix... PLENTY of them!

I've got to get a new batch ready to upload in a day or so... when I finish with the 1st layer of gypsum on the walls... then when I finish the 2nd layer.

[edit]Almost forgot... the size of the room/ceiling (for perspective) is roughly 18x28... but with the odd shape, it's impossible to give an accurate measurement[/edit]

 

[walnutjerry]

Max---------My experience with bending oak has been primarily with green wood that has been riven out of the log versus having been sawed out. The key to my success is getting the piece I am working on worked out parallel (sp?) to the grain. You rarely find sawn lumber that has growrth rings parallel to the edge of the board. In my case that would not work-----the piece would break before the bend was completed. In your case I do not think it is a major factor because of the amount of twist you mentioned.

Just for a visual test----take a piece of oak and see how much twist you can put in it before it breaks. That will give you some idea of what you will be facing in the real installation.

Jerry