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Discussion Starter #1
Knowing little about either, has any one used RSIC clips and ceiling mounted a (heavy) CRT projector?


Looking at a the unistrut method of mounting at Curt's site, it looks like your mount is directly attached to the studs.

http://www.curtpalme.com/MountingMethods.shtm


Its not clear to me if you essentially leave the CRT "area" unfinished (minimal drywall) and then try to enclose the space with a hushbox to trap the noise of the projector in the box, and the noise in the room?


What am I missing?
 

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Here's what I did.


I took a 3/4" sheet of plywood that was cut down to a 4' x 3' piece.

I mounted some long bolts into this plywood piece in the pattern to match the projector's mount.


I then attached the plywood directly to the bottom of the joices; it was wide enough to span 3 joices so there were enough bolts/screws to hold the weight of the CRT (about 160 lbs).


I then installed the RISC-1 clips, hat channel, double drywall like your normally would. The only thing left extending below the drywall when all was done were the 4 bolts to attach the CRT projector mount to.




This way, the weight of the projector is being supported by the joices, not the RISC-1 clips. And it was easy to seal since the only part produting were the bolts which could easily be caulked with acoustical caulking.



--curtis
 

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Thanks Curtis. That makes sense. I was hoping you'd respond since yours is a DE design w/CRT. I assumed that RSIC was in the spec.


I wasn't thinking RSIC until DE pointed out that its pointless to stagger studs w/o a similar treatment on the ceiling. Been reading here for a couple years and still forgot about the aquarium test.


Tricky stuff. The pictures are helpful.
 

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Yes, the design of my HT spec'd using RSIC-1 clips, and double layers of drywall. Green Glue did not exist at that time so wasn't used.


BTW: Dennis is the one who gave me the idea of using a sheet of plywood attached to the joices. I can't take credit for thinking that up myself!


--curtis
 

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Thinking about this again. . . . The thing that comes to mind is how well the Plywood Curtis used fit with the RSIC clips. Assuming I substitute a piece of strut instead of plywood to attach the bolts to, I am wondering if there is enough clearance for the hat channel ro run normally over the product supporting the mount (a piece of plywood (1/2"? or 3/4"?) or in my inclination, strut (can be gotten with a 13/16" height).


By doing a little math, it appears that the space between the joist and the hat channel is 3/4" (or 6/8" or 12/16"). Makes strut a bit too big, or would make 1/2" plywood okay. Is the threaded area on the RSIC clip something to adjust the height? Could I insert washers between the clip and the joist w/o hurting performance?


This picture might explain what I am thinking about. I know Don skipped RSIC where the PJ would be mounted.




On the left is the diagrams of RSIC. . . . . . . . On the right is a diagram of the Strut Channel.
 

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Dave


How about using a large "L" bracket bolted to the joist? This would be positioned far enough up into the cavity between the joists that when the unistrut is attached to the bottom of the "L" bracket that the unistrut wouldn't be below the RSIC clip. If you spread the unistrut across 3 joists, then you would have an "L" bracket at each joist.


This idea might work for 2"x12" joists. Of course if you have an "I" beam type of joist, back to the plywood idea.


George
 

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FYI: I just installed the plywood method attached to joists between the hat channel. I belive that I used somewhere between 5/8 and 3/4. I know it was larger than 1/2.
 

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George & Starbuck - -


Actually, I think it solved itself. In post #5 above, was trying to figure out if the RSIC would push the hat channel out far enough to hang the bolts down off, and not have the strut cross the channel. I was close, within a 1/16th.


Then I went out of town for business, and my carpenter forgot about RSIC and attached strapping to all the joists. The plan now is to attach strut to the joist (removing the strapping on the affected area), and then in the other spots attach the clips to the strapping. The strapping will give me plenty of clearance. Then put the lag bolts on, attach the sheetrock (2x + GG) with the bolts hanging through just like Curtis did.


Just need to buy the strut now, and cut it to size. My wife bought me a sawzall for christmas. Good times. Coming soon.


The L bracket would have worked though, or the plywood although I wasn't sure if that would have affected the height..
 
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