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Discussion Starter · #1 ·
I have an Electrohome 9500LC which I believe weighs about 225 pounds. It needs to be hung from the ceiling, which consists of 2x10 joists, around 16" on center, covered with 1 1/8" sheetrock. These joists are offset from the joists above which support the floor at the next level, so they are not yet weight-bearing. I have the mounting brackets. The plan is to secure some 3/4 " plywood to the ceiling, and then hang the mounting brackets from the plywood. (I'd prefer mounting the plywood over the sheetrock rather than cutting it to expose the joists.) I think the plywood can be made large enough to span several joists to spread the load. I'd love to hear from anyone who's mounted a projector on a ceiling with 2x10 or 2x12 joists rather than beams - in particular, what size lag bolts (width and length) to use to secure the plywood to the joists and the projector to the plywood. Any other suggestions or insights appreciated.


Craig
 

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you know i seen something cool done on wearhouse warriors on diynet tv.. beasicly it was threaded rodal going down so a platform that supported the tv.. the they had 4 more rods closer together the housed some of the components.. they used 3/4" ply and molding for triming it out.. check out www.diynet.com and search thier ep list.. look for the home entertainment show..
 

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I have 2x10s 16" on-center and a 225 pound Sony 1292.


I used 16 3/8" x 2" lag bolts with standard washers to secure my unistrut to the joists (beneath 1/2" sheet rock). Note that not drilling appropriate sized pilot holes will lead to splitting.


SOP here is to use unistrut rather than plywood - it's more rigid so it'll distribute the load better, and it will give you more flexibility in the exact mounting location. To keep the height lost reasonable, you can have the projector mounting plate above lower pieces of unistrut.


Plywood has voids and I've had screws pull-out so I would NOT hang any weight from a fastener threaded into it. A large T-nut on the backside would be better.
 

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Drew I have a question for you.

I will be putting my XG up soon. What is the best way to mount it without loosing any unnecessary head room. Thanks
 

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Make sure your unistrut spans 3 joists, or more, so that the weight of your projector is distributed across 3 or more joists. This brings the weight per joist to 70 lbs or less.


Excellent point, regarding drilling pilot holes in the joist. I was able to put my unistrut above the horizontal member of the rafters, so the weight is distributed on the top of the wooden member - no pull-out concerns.


Craig might consider using an "L" bracket bolted through the side of the load bearing joists using a standard thread 3/8" bolt with a lock nut. This would be better than using a lag bolt, which could cause concerns of the wood splitting. There would be no way the bolt could pull out. The unistrut could be bolted to the horizontal member of the "L" bracket. In this case the unistrut would run parallel to the joist, rather than perpendicular.
 

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Not only should you pre-drill, you should also lubricate. I used a bar of soap, and took turns from one lag to the other. If that lag heats up, it will snap.
 

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I used five 8" lag bolts to secure two unistrut lengths to the ceiling. The unistrut spanned 3 joists. Probably overkill for my 120 lb CRT, but I wanted to be sure. I predrilled through the drywall with a 1/8" bit to locate the joist center, and then predrilled the holes in the center of the joists for the lag bolts. I should have lubricated them as patrick suggested because man were they tough to turn those last couple of inches.


Tim
 

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When you are talking about something heavy enough to kill an adult you want to be absolutely sure. Especially if you have never done anything like this before. It is your call but I would cut the drywall out and go over the joist not under it. You can easily construct a few long "U" bolts by using unistrut or angle iron and threaded rod. At the bottom of the "u" bolts attach a length of strut or iron and then bolt the PJ brackets directly to the that. If you need to make the mounting flush with the bottom of the joist or at the level of the ceiling you can notch the bottom of the joist to accomodate the strut. Hanging over 2 joists is better than mounting under 4. It will take more time granted but you will never have to wonder if the wood fibers are going to hold those lags in the years to come. I am not being critical of those that have I am just saying I would not. You can mount a porch swing from two lag hooks and it may hold for 20 years. The worst that can happen upon a failure is that you fall 2 feet on your butt. Not the case with an overhead PJ.
 

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I put 6 lag bolts into the three joists in my celing and it held a double stack of NEC XG-110LC's for about a week before I pulled one projector down. I will put it back up in a little bit, but I am not worried at all about the weight. My load was pulling down about 3' from the back wall, though, so I wouldn't expect much sag.
 

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If you take a look at my gallery you will find 2 pics of how I mounted my marquee 9000.


I used a 2X4 bolted to the joist and then bolted the unistrut all the way through it this allows side to side adj and then used the 2 hole tabs to run threaded rod down to another run of unistrut fore/aft bolted to the bottom of the proj. this give me lots of adj room. the fact that all the bolts are backed up with big fender washers and everything has RED loctite on it .......... I am sure it wont be going anyware ..... oh and they are bolted to doubled up joists but they are only 2X8's


if you have any ???? ask or Pm me


Kevin
 

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Craig,

The most common way to do this is with Unistrut as mentioned. You didn't say whether you had a projector mount for your 9500. The mount makes it easy to adjust the tilt. I use installed unistrut on 3 joists and then have 2 pieces of unistrut going perpendicular that are attached to the 3. That gives full X-Y adjustment. I did not use lag bolts but instead used heavy duty L-Brackets from a surplus store and bolted them through the joists. Home Depot has most of the hardware. The mount for my 8500 is then fastened to the unistrut. With an 8 foot ceiling I still have just over 6 foot clearance to the floor. The best way to lift the projector into place is with a Genie lift. It is still recommended to be a 2 person job but the Genie lift makes it easy and the rental is about $30 a day at the A-1 tool rental place in Campbell. (pick it up on Saturday morning and return Sunday morning) I have pictures I can send you of my installation in Sunnyvale. PM me if you need more info.


.. Doyle
 

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Quote:
Originally posted by ArtisTech
Drew I have a question for you.

I will be putting my XG up soon. What is the best way to mount it without loosing any unnecessary head room. Thanks
I really need to print + scan my pictures of this.


Your basic unistrut mount has pieces running parallel and perpindicular to the screen. While people usually have all their unistrut between ceiling + projector there's no reason to.


I have 3 pieces lag bolted to the joists parallel to the screen (I think 2 would work but would look at the uniform building code for live/dead load before counting on it). The two pieces (> 3' long) perpindicular to those hang beside the projector with the open end towards the ceiling. My projector is bolted to 1/8" x 2" x 1/2" C-channel which sits on top of washers and is in turn bolted to channel nuts in the unistrut. The washers (you could also use steel plate, unistrut joint pieces, etc) are the second trick - they allow you to lift the projector higher than you could without making it impossible to get at the mounting hardware.


As long as the C-channel (1/4" plate might be stiff enough, although you still have the bolt heads on top adding to total height so you might as well use the channel) doesn't line up with a parallel member the height lost is the difference between the projector's feet and the unistrut height (5/8" or 1 5/8") - under an inch in my case.


If you had the parallel screen members in front and behind the projector, any height of the c-channel above the feet would be the limiting factor. My projector has 3/4" feet from the factory so if I did this I'd have a "0" thickness mount (large dimensions led me to duct air above the projector instead of to the side, so I wanted a little space up there).


If this isn't enough, feel free to ask more specific questions.
 

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Thanks for response.

In my case with a low ceiling of 7', I reinforced two runs with double stacks full length 2x10 (thank you Doug). Then I cut the hight about 3.5" in order to recess the PJ into a 30"Wx45"L cavity.

Hence I have two available reinforced trusses that are parallel to the screen. I am looking for a way to mount the PJ in zero hight (level with bottom of truss) if possible. That would be eliminating any c-channel in between.


I will use threaded rods(10mm) into place of the feet's female thread and would like to attach these to L-brackets (or simply c_channels) that are attached to the side of the trusses. The method of attachment is what I like to find out that would leave the PJ a little wiggle room for possible future alignments. Any thought would be appreciated. I understand it is a hypothetical situation.
 

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I also used Unistrut. I agree with the recommendation to cut away the sheetrock to solidly locate the joists. I only cut a small window away, enough to ensure that the two holes on either end of the piece of Unistrut were 100% centered. I also held a square up to the ceiling to ensure that the drill was going squarely up into the meat of the joist.


You can see step-by-step pictures of how I used Unistrut in my photo album . Click on one of the initial pictures dated January 3rd 2002. This will bring up the picture and a descriptive caption. You can then step through with the Next button. Please don't hesitate to ask any questions.


There are also some pictures from August 10th 2002 which show a novel method using long threaded rods so that one person can lower and raise the projector alone. I first read of this method elsewhere on this forum.


- Chris
 

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Craig, go with a nice DLP PJ and you avoid the weight and scan fails.
 

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Discussion Starter · #16 ·
HomeTheaterGuy:


Yes, and all that confusing picture detail.


By the way, Hi-Rez Projections suggests using plywood and not Unistrut because it can get magnetized. Who knows?


Craig
 

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Sam said his CRTs still have the smoothest picture, but he also fore-casted the end to Runcos CRT parts would be soon. I was going to get a color analyzer and avoid the prciey ISF calibrations, but my Barco scan failed on me :( So I went the DLP route. I like the picture. Bright and colorful. But if folks want to keep their CRT let them. They have great black levels.
 

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My joists run perpendicular. If I run two 4' lengths of unistrut across 3 joists and then attach my PJ to that will I be OK?


I'm trying to save some headroom by not doing the set of parallel unistruts. As long as I get in centered then I will still have the ability to move the PJ backwards and forwards.
 
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