Opinions on how to ceiling mount my Sanyo Z4 FP

761 Views 3 Replies 2 Participants Last post by tmnjus, Oct 2, 2006

cjbaldw

Discussion Starter · Oct 1, 2006

All,

I've recently purchased a Sanyo PLV-Z4 projector as part of a combination family room/HT buildup in my basement. I've already wired power and a 2" PVC run through the joists to the area that will house my a/v equipment (roughly 10 feet away from the ceiling mount location itself). Drywall ceiling already installed. I've purchased the following ceiling mount equipment:

Chief CMA-345 isolated ceiling mount

6" 1 1/2 inch threaded pipe

Chief RPA-U FP mount

The 1st part is a mount designed to minimize ceiling vibrations. It has three sets of screws roughly 6" apart and I've been trying to figure out the best way to mount the CMA-345 to my drywall ceiling and the underlying joists (16" centers). Here's a picture of what the CMA-345 looks like:

http://www.standsandmounts.com/Produ...ief/cma345.jpg

So, the three sets of screws on each side of the mount, are just a tad more than 6" apart. Since my centers are only 3" in width in the ceiling that I can screw into, I was perplexed as to how to mount this directly to the ceiling.

I saw another guy on here use a piece of MDF mounted to the ceiling, and then he mounted 12" pipe to the MDF, though I didn't see any specs on the MDF (thickness, etc.) so I want to make SURE I do this right given I spent what is to me quite a bit of money on the FP itself.

I picked myself up a 3/4" thick piece of MDF from Home Depot, 2 x 4 feet long. My plan is to cut a piece of MDF roughly 20" L x 12" W. I'd then pre-drill 3 holes into each side of the MDF equidistant to each other with a countersinking bit, and I'd pre-drill a total of 6 holes into the middle of the MDF to match the hole pattern required by the CMA-345, so that the CMA-345 would end up centered on the MDF board. I'd then use 3" countersinking lag screws to secure the MDF to the ceiling, and I'd use 1" lag screws to secure the CMA-345 to the MDF. Does my description make sense?

Once that's done, I'd install the 6" 1 1/2 inch threaded pipe into the CMA-345, then do whatever is necessary to install the RPA-U onto the Z4 and connect it up to the other end of the threaded pipe (never done this before so I can't really describe what to do).

My question is, is 3/4" MDF "safe" enough, can it support the weight of the CMA-345, the RPA-U, the pipe, and the Z4 safely? Should I use real 3/4 inch oak instead?

Much thanks in advance for any advice!

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tmnjus

· #2 · Oct 2, 2006

Personally, I would go with Oak, but you should be ok with MDF. The follow link talks about using screws with MDF. I'm not sure about the holding strength of lag screws for the CMA-345. Find ones with the "fattest" thread.

My concern with lag screws is that you should have a washer behind it to prevent the head from sinking in. You may be better using 3" sheetmetal screws (#12 or #14) and space them about 3" apart to attach the MDF to the joices. Wood screws would work as well.

http://www.norbord.com/images/screws...%20strength%22

Would it be feasable to cut out a section of your ceiling sheetrock and install some wood backing between the joices? If you have ever taped / mudded sheetrock before, you should understand the effort involved. This would give you a cleaner look, and you would not need to use the MDF. Just a thought.

Tom

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cjbaldw

Discussion Starter · #3 · Oct 2, 2006

Quote:

Originally Posted by tmnjus
Personally, I would go with Oak, but you should be ok with MDF. The follow link talks about using screws with MDF. I'm not sure about the holding strength of lag screws for the CMA-345. Find ones with the "fattest" thread.

My concern with lag screws is that you should have a washer behind it to prevent the head from sinking in. You may be better using 3" sheetmetal screws (#12 or #14) and space them about 3" apart to attach the MDF to the joices. Wood screws would work as well.

http://www.norbord.com/images/screws...%20strength%22

Would it be feasable to cut out a section of your ceiling sheetrock and install some wood backing between the joices? If you have ever taped / mudded sheetrock before, you should understand the effort involved. This would give you a cleaner look, and you would not need to use the MDF. Just a thought.

Tom

Thanks for the advice, I wasn't aware of the use of sheetmetal screws over wood screws when it comes to MDF.

To answer your question, I could cut out some of the drywall, but I'm not at all skilled when it comes to drywall finishing. I'm more of an infrastructure kind of guy, i.e. I did all of the design, framing, electric, HVAC, gas pipe extension, insulation, and drywall installation, however I had someone else do the actual mudwork and taping. I've tried it myself and it's more of an art kinda thing that I have too little patience to deal with, though I've managed to do smaller patch jobs successfully. So what're you suggesting, cut out a section of the drywall and install a piece of oak or something along that line into the cut out area? Hmmm...that's not a bad idea and that'd be a pretty easy patch job to boot. Lemme know if I'm understanding what you're saying correctly!

Thanks much!

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tmnjus

· #4 · Oct 2, 2006

Basically, you want to put some bracing between the floor (ceiling) joists where the PJ is going to mount. Here is what I suggest, but I'm sure others have different ideas as well...

Make sure you identify where the existing joists are. You are going to want to cut out a piece of the ceiling sheetrock between the joists, and as long/wide as you think you need it to be.

Once you have the sheetrock out, you would install some , 2x8, 2x10 (or whatever you can get) between the joists. Nailing these in place can be the difficult part. You would need to toenail the 2x? piece of wood into the joist at the 4 corners. I would use nails vs screws since nails have greater lateral strength. You may be able to come up with some 90 degree angle brackets to nail into both the joists and the 2x? (Bigger the better)

An alternative (and much better) method to toenailing would be to cut out the sheetrock that would open up the joists on either side of the target one as well. Then you can nail through the joists on either side into the 2x? wood. The problem with toenailing is it can be difficult to get a good enough "bite" of the 2x?, and may not be as strong. Either way, I would also glue the sides of the 2x? to the joists with construction adhesive.

Once you have the 2x? in place, cut a piece of SER (or use the one you cut out if you did it carefully) and place it in the hole. If you only opened up one joist space, you can screw the SER directly to the 2x?. If you opened up more then one joist space, make sure you cut the SER (when removing it) on the center of the 2 end joists. This will give you something to screw into when reinstalling the SER.

Now that I've typed all this and thought about it, I definately would recomend the alternative method (driving nails through the joists into the bracing). This would give you the strongest connection.

This sounds like something you would be able to do, but considering the mess / time involved, I would most likely just mount a slab of wood directly to the ceiling as you planned! Painted the same color it shouldn't be too noticeable.

Good luck!

Tom

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