Just ordered an OmniMount UCLX (dual arm wishbone cantilever, 35" extension, 200lb weight limit) for a 70lb 50inch Pioneer panel. I read Iago's thread from last week but have a different issue. The room configuration requires the mount to be mounted spanning a double hung window, so the stud spacing is approx 44". My concept is to attach 2 2x4 studs outside the plaster, bolted to the existing studs with 3/8" lag bolts (sandwiching the plaster and lath). These can be 6 foot tall and touching the floor to take some of the load. I'll then span in front of the window between those with with 2 2x10's behind a 4x5 foot panel of 3/4" baltic birch plywood (which I can paint as a background panel and will block any backlight from the window). This can be attached to the upright studs with several 3/8" lag bolts. The UCLX has a cast 21x32" back plate with plenty of 3/8" bolt holes to through bolt and lag bolt into the 2 1/4 " of the plywood and 2x10's. This sounds like overkill to me and uses construction usually used on house decks which support several 200 lb people without a problem. I welcome any helpful comments or sugestions regarding my plans (other than "hire a pro" as I am quite capable with this type of construction).

I didnt want to say hire a pro, but there are so many things u are not taking into consideration.
ur dealing with an exterior wall. if it was me i'd fur out the whole wall w 2x4s, only bcuz it would be weak in the widow area. how are u gonna get power, and or any type of video feed, and any spot for a center channel speaker, let alone, never mind hire a pro.
or... you could just build an outside deck, with surround, BB-Q, and watch the Patriots lose.

I would remove a section of drywall, reinforce the inner wall with studs and cross braces. Then re-drywall. All this can be done in 2 days with waiting for the mud to dry. Actual time of work should be about 3 hours.

The installation is centered in the end of a 12 foot wide room. The end of the room is not rectangular but is a bay with three walls angled out, with a window in each wall (six foot wide wall with four foot wide angled corner walls). I cannot fur out the center section as the angled walls also have windows. As the plywood panel will be mounted to “float” three inches in front of the wall surface, there is room behind for the cables and the center channel can also be mounted to the plywood panel. A 30” high AV cabinet will hide the two 6 foot 2x4 posts that extend below the plywood and touch the floor. As the inside corner studs of the “bay” are within a foot of the studs on each side of the window being spanned, the wall is quite strong.

The concern is the torque of the 70lbs extended 35 inches. The load will be torquing (twisting) the 4 foot horizontal 2x10’s and also be tensioning (pulling) all the bolts where the vertical posts are attached to the wall studs behind the plaster. The plywood panel should help with the torque by keeping the 2x10’s from twisting. I can also double up the vertical posts above and below the horizontal 2x10’s to further attach the plywood “skin” panel which will transfer much of the weight to the floor (or use 4x4 posts and notch them for the horizontal members).

The midpoint of the mount will be 48” above the floor and the top of 5 foot wide plywood panel will be at 6 foot and extend to just below the height of the 30” tall 60” wide A/V cabinet.

I do not want to remove the window from the building, the plan is for this 6 ft tall x 4 foot wide plywood skinned structure to act as a secondary supporting wall mounted firmly inside the room to the existing wall (spanning the window).

hire a pro....

Hello, I need open heart surgery. I have read the Boy Scout First Aid manual, so I think I can pull it off. My question is do I start cutting the incision from the top, or bottom. Please do not suggest I contact a Heart Surgeon, as I am handy with a knife....

Man you guys are tough! I’ve done house construction, furniture building, and installed a custom sunken bathtub weighing over 1500 lbs when full. Hanging a 70lb weight is not rocket science or brain surgery. Just thought I’d double check my plans with the experts who might enjoy a challenge or have some insightful input. I certainly wasn’t expecting the attitude (hardly professional). I’ll dig out my structural engineering textbooks from college and do the calculations. If I have no luck I can always hire a professional Structural Engineer (or just skip the wall mount and use a stand).

This message was edited by eastham on 10/30/05 20:11 ET.

It sounds to me like you are over-building the hell out of it, and that is what I would do. Sounds totally reasonable. My only issue is the Omni mount. (do a search). I would recommend the Chief. Otherwise, go for it!

Make a pedestal stand from metal tube. Bolt it to the floor. Sleak, and strong. Wires can be run inside tube(s). For what you are paying for the mount, you can afford a few hundred bucks to have this fabbed-up.

Draw-up some plans, and take them to a metalshop/welder. You can then paint, or wrap with wood.

This message was edited by LouC4 on 10/30/05 23:50 ET.

At the end there, a real phrase in English.

This post reminds me of the hip hop guy who couldn't get a job at the Ford plant in Detroit. The manager running the assembly line figured that if the guy couldn't tie his shoes, he damn well couldn't build a car.

The same thing goes for pants crotches at knee height and language as above. You have all the letters on the keyboard and want to communicate. Why not use what you've got?

LMAO!