I need framing ideas for a "floating" screen with no back wall to support it

**tweakophyte** · **04-05-08, 09:10 PM**

Hi-

I need some ideas on what substrate to use and how to mount it for a screen that will "float" about 2 feet away from the current screen. If you take a look at my attached picture, you can see my current screen is paint (MMud) on the wall in an area that is about 89" wide by 2.5 feet deep. It works great, but now that I have an HD projector, I want to move the screen itself forward by 2 feet. This is to give me the effect of a large picture.

The net of it is I'd like to figure out a way to mount a screen with no back wall to use as a support. Right now I have a sheet of doable. I was originally thinking of building a frame on edge and glueing (via liquid nails) the doable onto that frame. (When I say "frame on edge" think of it as building a platform out of 1x3s or similar wood.) The goal is to have something that will not warp.

I went into HD today and got into analysis paralysis. Which wood would be best to use without it warping? Would glueing the doable onto the wood cause it to warp? Can I do this without clamps? Do I even need a frame? Should I just use 3/4" MDF (jeez that is heavy!). I went in thinking I'd use 1x3 poplar, but the guy in the store wanted me to 2x2 pine. He was very helpful, but I walked out of there with nothing.

After I figure out how to stiffen the doable, I am thinking of attaching some eyelets of some type and hanging it from wire, suspended from the side walls. (The top part of that screen area will not support wieght... just a ladder hiding some ducting.) If I can do that the screen will essentially float, and any light-spill will get lost behind the screen.

Am I making sense?

I am wondering if I should just glue a 2x4 across the back of the doable, then screw in another 2x4 at a 90 degree angle to prevent the wood from bowing. Will the weight of the doable enough to keep it flat?

Am I making sense?

Any ideas?

Thanks,

**mechman** · **04-06-08, 12:14 AM**

Quote:

tweakophyte wrote:

Hi-

I need some ideas on what substrate to use and how to mount it for a screen that will "float" about 2 feet away from the current screen. If you take a look at my attached picture, you can see my current screen is paint (MMud) on the wall in an area that is about 89" wide by 2.5 feet deep. It works great, but now that I have an HD projector, I want to move the screen itself forward by 2 feet. This is to give me the effect of a large picture.

The net of it is I'd like to figure out a way to mount a screen with no back wall to use as a support. Right now I have a sheet of doable. I was originally thinking of building a frame on edge and glueing (via liquid nails) the doable onto that frame. (When I say "frame on edge" think of it as building a platform out of 1x3s or similar wood.) The goal is to have something that will not warp.

I went into HD today and got into analysis paralysis. Which wood would be best to use without it warping? Would glueing the doable onto the wood cause it to warp? Can I do this without clamps? Do I even need a frame? Should I just use 3/4" MDF (jeez that is heavy!). I went in thinking I'd use 1x3 poplar, but the guy in the store wanted me to 2x2 pine. He was very helpful, but I walked out of there with nothing.

After I figure out how to stiffen the doable, I am thinking of attaching some eyelets of some type and hanging it from wire, suspended from the side walls. (The top part of that screen area will not support wieght... just a ladder hiding some ducting.) If I can do that the screen will essentially float, and any light-spill will get lost behind the screen.

Am I making sense?

I am wondering if I should just glue a 2x4 across the back of the doable, then screw in another 2x4 at a 90 degree angle to prevent the wood from bowing. Will the weight of the doable enough to keep it flat?

Am I making sense?

Any ideas?

Thanks,

If you're looking for wood that will not warp, get the kiln dried hardwoods. I used poplar for my frame way back when and it hasn't warped at all. I used maple for the velvet 'outer' frame and that hasn't warped either. If one was to really be particular about it, you could seal it all with polyurethane after making the cuts and putting it together.

**tweakophyte** · **04-06-08, 08:17 AM**

How is the poplar frame mounted? It seems many of the solutions people come up with are mounted on the wall, which should keep most solutions flat. This would be free-standing, hanging in the air.

The guy at HD made it seem like poplar would warp just like any wood, besides the fact that many of the pieces were already warped.

**mechman** · **04-06-08, 12:55 PM**

My frame is mounted on the wall with a french cleat I made out of a 2X4. Poplar, as any wood, can warp However the chances of poplar warping over a soft wood such as pine, spruce, etc. are much slimmer. You could go all out and get oak or mahogany.

But then it starts to get expensive. If you're worried about it warping just seal it as I said and then put it together. It's the moisture in the wood and in the air that causes most of the wood warps. If you seal it out it shouldn't warp!

Check the lumber for straightness when you buy it. I usually hold one corner and look down the length of it looking for bows and warps. Choose lumber that has the least knots as well. If this is something that won't be seen you may just want to build it out of plywood.

**solid7** · **04-06-08, 01:03 PM**

Quote:

tweakophyte wrote:

The guy at HD made it seem like poplar would warp just like any wood, besides the fact that many of the pieces were already warped.

When you want good advice, (or wood, for that matter) you don't ever want to ask someone at HD. That's DIY rule #1.

**Harpmaker** · **04-06-08, 04:05 PM**

Hi Tweakophyte,

First, the numbers for Doable (using the XYZ figures from AVS) are:
L*a*b* = 89.533331, 3.843623, -4.271671
D65 degree Color Temp = 6741.7

These were obtained by using the calculator at http://www.brucelindbloom.com/index....alculator.html

As for mounting your Doable, how flat is the panel itself? What finished screen size are you after and how large is the Doable sheet? I'm also assuming it's 1/4 inch thick. Sorry if you've given this info before.

As for sealing wood with poly (or anything else)... I wish it were so. Unfortunately all wood finishes do is slow down moisture migration, not stop it. Some are better than others (poly is the best that is available to the home-user). One tip, if you finish a piece of wood, finish BOTH sides. Only finishing one side can actually CAUSE a board to warp due to uneven moisture absorption.

In my experience, plywood thinner than 3/4 inch will curl unless it is prevented from doing so by nails, screws or glue. The exception is Baltic Birch plywood which has many more plys than regular PW and is voidless. It's really nice stuff to work with, but a bit expensive.

**mechman** · **04-06-08, 06:28 PM**

Quote:

Harpmaker wrote:

As for sealing wood with poly (or anything else)... I wish it were so. Unfortunately all wood finishes do is slow down moisture migration, not stop it. Some are better than others (poly is the best that is available to the home-user). One tip, if you finish a piece of wood, finish BOTH sides. Only finishing one side can actually CAUSE a board to warp due to uneven moisture absorption.

Not only both sides but the ends as well. This is why you'd want to cut it first. Another thing to ask is do you keep your home's humidity level in check? Adding in the winter and removing in the summer? While I said moisture is the cause of warpage, I didn't elaborate. It's the constant fluctuation between dry and wet that really causes the warps. As I said, I used poplar from HD and it's been up for over 16 months or so and there's no signs of warping. And it's not sealed at all. if I were to do it again, I'd probably seal it.

**tweakophyte** · **04-06-08, 08:25 PM**

Quote:

Harpmaker wrote:

Hi Tweakophyte,

First, the numbers for Doable (using the XYZ figures from AVS) are:
L*a*b* = 89.533331, 3.843623, -4.271671
D65 degree Color Temp = 6741.7

These were obtained by using the calculator at http://www.brucelindbloom.com/index....alculator.html

As for mounting your Doable, how flat is the panel itself? What finished screen size are you after and how large is the Doable sheet? I'm also assuming it's 1/4 inch thick. Sorry if you've given this info before.

As for sealing wood with poly (or anything else)... I wish it were so. Unfortunately all wood finishes do is slow down moisture migration, not stop it. Some are better than others (poly is the best that is available to the home-user). One tip, if you finish a piece of wood, finish BOTH sides. Only finishing one side can actually CAUSE a board to warp due to uneven moisture absorption.

In my experience, plywood thinner than 3/4 inch will curl unless it is prevented from doing so by nails, screws or glue. The exception is Baltic Birch plywood which has many more plys than regular PW and is voidless. It's really nice stuff to work with, but a bit expensive.

Cool site. Btw, I used just the RGB (which I am sure is less accurate than the XYZ) and D65 reference and got a color temp of 6728. I guess I am not nuts for noticing the blue push.

Doable is 1/4" thick. The dimensions are a little less than the standard 49" X 87" (I forget and am too lazy to find my paper with my exact numbers). I got it with the intent of using the tempered masonite side in mind because I wanted to make some BW. For $16 is it a nice piece of material. It sounds like the white (blue) side is good to paint on, too.

In the context of this thread, the goal is to help my figure out the best way to get some kind of substrate to float. If MDF is the way to go, it's the way to go. I don't want to force dobale into the solution if it's not worth it.

That said, it sound like I may want to use poplar. Part of my is thinking I could make the frame on edge, then use liquid nails and some finishing nails to mount the doable. I'd do this with the intent of sinking and spakling the nails... sound like a PItA.

Has anyone suspeded MDF with no framing? How thick would I need to prevent warping and how heavy would that sucker be? Assume it's 49" X 87".

**tweakophyte** · **04-06-08, 08:32 PM**

Good comments on sealing the wood. I am in CO where my harwood flooring gets wavy if I forget to turn on the humidifier in the winter. We cycle between nicely dry and pretty freakin dry. We had our front door that warped and was replaced under warranty. With the replacement, the door manufacturer made sure the builder sealed the door... top to bottom. The first one was not and it showed.

I am handy, but have no tools. While I was in college my step-dad worked at a custom shop... I'd take high-end veneered wood and make subwoofer boxes. Prior to that, and when I was in woodshop in high school, my mom worked at a fine hardwoods shop. I made a bunch of skim boards out of Finnish birch plywood. I turned a sweet bowl out of Koa... etc... Since then my brain has forgotten everything.

**Harpmaker** · **04-06-08, 10:18 PM**

Quote:

mechman wrote:

Not only both sides but the ends as well. This is why you'd want to cut it first.

Correct, but don't finish ends that will be glued; bare wood takes glue much better than finished wood.

On end grain that will be visible, it's also a good idea to make "glue size" (just thin the glue, I assume it's water-based, about 50/50 with water) and brush or dab it on until it stops being sucked into the wood. The end grain will suck it up via capillary action and, when dry, this will seal the grain. Sizing the end grain before gluing prevents a glued joint from "starving" (the glue gets sucked into the wood and doesn't stay in the joint) and creating a weak joint. Sizing is also good for sealing end grain if you want to stain or finish since it won't absorb more stain or finish than the long grain and look darker. Sorry, this is probably more info than needed or wanted.

**mechman** · **04-07-08, 07:51 AM**

I threw out the glue when I got my pocket hole jig! lol! I think Don and I could go on for days!

**cynical2** · **04-07-08, 08:36 PM**

BTW, tweakophyte...you may also want to consider metal studs. Cheap, lightweight, and straight as a string.

Oh, and I guarantee they WON'T WARP...even if you don't seal them

**tweakophyte** · **04-07-08, 08:52 PM**

Quote:

cynical2 wrote:

BTW, tweakophyte...you may also want to consider metal studs. Cheap, lightweight, and straight as a string.

Oh, and I guarantee they WON'T WARP...even if you don't seal them

How much to they go for and where can I get them? I don't think I've seen the at HD or Lowes. Can I use glue or will I need to screw?

**cynical2** · **04-10-08, 07:24 PM**

Quote:

tweakophyte wrote:

How much to they go for and where can I get them? I don't think I've seen the at HD or Lowes. Can I use glue or will I need to screw?

Yes, both Lowe's and HD carry them. They can be glued with construction adhesive or screwed with sheet metal nails. You have to be careful about gluing with some substrates...you can accidentally create waves. Look in the laminate sticky for more info on that.

Also, if you use glue, make sure you trowel it down so the glue lays flat when you attach the substrate.

I remember seeing someone who cleverly integrated metal studs in their design...but I'm drawing a blank. You may try searching around some more...I did a quick look and couldn't locate the discussion.

**muzz** · **04-12-08, 09:50 AM**

IMO, Metal stud frames should be screwed together with self tapping/sheet metal screws.
You can use simple corner braces for the four corners, or if you good with metal shears, you can make a tab out of the actual metal studs themselves.
You could drill pilot holes along the edge of the screen substrate, and then screw it to the metal framing along the edge.
I would start from the middle of the top rail, and work your way out to the edges, then down to the bottom along the sides.
Be careful when screwing the substrate onto the frames, plowing the screw with too much torque will pull the screw head right through the substrate, most modern drills have a torque setting that you can adjust to stop it- you set it so it sets the head just right.
I would use "Flat head" type screws, so the head will be countersunk(watch the depth of the countersink- don't let it pull through!).

That would be how I would do it, other opinions may vary.

**basementjack** · **04-12-08, 12:55 PM**

my 2cents...

I found the metal studs much harder to work with than I expected them to be, and while they don't warp per say, it was nearly impossible to make a perfect box that wasn't warped front to back on one corner.

-----------------------------

I would suggest using a french cleat like mechman did.

in fact, I'd probably do the french cleat to the rear wall, then contruct a box to 'float' the screen and put a french cleat on that - then you'd have the option of removing the float box and going back to the wall pretty easily.

**tweakophyte** · **04-14-08, 07:50 AM**

Thanks for all of the comments, guys.

**tweakophyte** · **05-02-08, 07:10 AM**

Well... it has been an adventure. I built the frame from poplar.

I was going to use the "thrify white tile board" as the stiffening backer. Well, when I first started cutting the frame at HD I dedided to power through and do 45 deg joints using their dull moulding saw in the cheap plastic miter box. (No, JD does not cut angles for you.) That took forever and at the end of my second piece I was off about 1/8". I took a different approach and just had them square the ends up.... but, because of that I forgot to keep my original measurements and when I got home I found the backer to be the wrong dimensions.

When I was drilling pilot holes for the l-brackets I went a little too deep on one hole. The problem is I was using the backside of my "perfect" peice of doable as a backer at the time. That means I made a bad bulge in it that would just not push back in.

I spend a ton of time at Home Depot... at my third one a guy actually helped me go through about 30 sheets. I could only find one that good enough. When I got that home I noticed a huge scratch on it. Grrrr...

I called a buddy over who helped push me over the edge on just going for it. In the end, I originally just wanted the doable so I could paint it, and viewing the doable was an interim step. We tested the doable and could not find the scratch... we shall see...

Anyway, he helped me lay the frame on the back of the doable. I decided to use the loctite construction adhesive because of the water clean-up. FWIW, I did some test peices, glueing some wood on a scrap of doable and TWTB... it did not pull, but I could tear each peice off if I wanted to (destroying the substrates). The loctite grabs right away, doesn't stink, and lets you make adjustments. It's kind of like silicon caulking and it fills gaps.

Monday night I took the flat loops you use for a 100lb hanging kit and attached them. I also cut a length of 1/16" steel wire and attached each end to a tightening turn-buckle using some aluminum ferrules.

Then I struggled for a little bit trying to hang it by myself... given all of the other foibles, I waited until a buddy came over to help. By the way, I am using those monkey hangers you see on TV where it is a meat hook looking thing you push through the wall. They hold 50 pound each. The screen is 40 pounds, max (according to my scale).

**tweakophyte** · **05-02-08, 07:11 AM**

And then... ta dah...

and with the back-lighting on (just for mood, not during a movie.

**tweakophyte** · **05-02-08, 07:12 AM**

Since the screen wanted to tilt down, it worked out that I could use a spare acoustic panel I built quite a while ago as a spacer behind the center speaker.

**tweakophyte** · **05-02-08, 07:16 AM**

Here's one screenie.

I have two problems I need to tweak out. The first is a little light-spill on 16:9 movies. The second is I have some pretty noticable pin-cushioning. I'm assuming it's from the steeper angle down and the additional zooming I had to do, i.e. it's the PJ and it's position.

This one is a little over-exposed, but you can see the bowing.

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