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DIY Adjustable Plexiglas PJ Mount  

post #1 of 98
Thread Starter 
I decided to build my first DIY projector mount, and designed around an idea I saw here, but using plexiglas instead of the typical plywood. Here is the process I took:

Here is the bottom (ultimately the top) of my BenQ PE7700 projector that I have to work with.


The holes are M6 metric threads, so I bought four 1" screws to mount the first layer of plexiglas to the PJ. I used 1/2" nylon spacers between the plexiglas and PJ to keep it straight -- it also rested on the legs which was convenient. The four long bolts (4" x 1/4") are used to attach to a second tier of plexiglas which is ultimately connected to a pipe.


I bought 1.5" galvanized pipe (12" long in my case) from HD, and two flanges, screwed them together, and painted them white for WAF. I also painted the screw heads for the lag screws that will be used to attach the flange to the joist.


Here is the finished product. I used wing nuts for easy adjustment, and it was very easy to fine-tune that way. I initially drilled slots for the attachment of plexiglas to flange and used wingnuts, in case I needed to twist the entire PJ around its vertical center, but it turns out that the actual pipe is at a happy-medium of resistance where I can just twist it to where it needs to be and it holds in place. We'll see how that works long term.

Also, I ended up being right on a joist, so I just used two lag screws (2.5" x 1/4") into the one joist, instead of all four.


If I hadn't been able to mount straight to a joist, or wouldn't have minded spending more time on it, I would've drilled a hole in the ceiling directly above the pipe, and a hole in the upper plexiglas tier to run cables through. I'll do it it that way when I build my dedicated HT.

I thought this may give others ideas regarding DIY mounts...

Oh, total materials cost was around $25 + plexiglas (I was able to get some for free) + spray paint.
post #2 of 98
Beautiful! How do you aim the projector square to the screen/wall?
post #3 of 98
Were you able to get it level? If you needed the flexibility to level things, I guess you could cut the 4" bolts in half and reconnect them with a turnbuckle on each leg - that way you have a tensioned "leveler" system to correct any slight imperfections.
post #4 of 98
Thread Starter 
Thanks Ron -- I just twist the pipe to the appropriate location, and there's enough tension that it holds in place. I'm not that worried about it getting bumped (not enough to put another adjustment mechanism in place that most likely is not needed).

Redhawk, leveling it was no problem -- I just loosened or tightened the four main wingnuts (on the outside) and it easily adjusted into perfect position. I was planning on putting in springs between the plexiglas (the bolt through the spring), or plan B was to just have wingnuts underneath the upper plexiglas piece to keep that top one together. The way it is now, the 15 lb projector is holding them in place just fine. If needed, I'll probably go with plan B as it will look better than having springs (and function better to be locked in place).

As it stands now, though, I could not adjust the mount any more and get a better picture (and that literally took ~60 seconds with the initial adjustment). If I didn't need the PJ so low, I'd probably use shorter bolts than 4" so they're not sticking out, but I do need that distance right now.
post #5 of 98
Nice job.
post #6 of 98
Great DIY job! Very nice done.
post #7 of 98
Cool!. It's a pretty aesthetic DIY mount, too!
post #8 of 98
RE: running the wires in the pipe. That's how I did it and I think it's much cleaner. You had to go up in the attic in the first place, so it's not that much more effort right? You also didn't have to make two plates. If you use longer bolts/screws that go directly into the PJ, you can hang it off of single plate and still have the kind of adjustment you have.


You can see my mini tuturial on this here:

Score another one for the cheapy DIY crowd!

post #9 of 98
Thread Starter 
Thanks for the post, Bobby... here are some of my thoughts (random or otherwise..) :)

- As I said, I couldn't run the cabling through the pipe because the upper flange is centered on a roof truss. I could move the projector and screen a few inches to one side, put a 2x8 between two trusses, and drill a hole through that 2x8 to run the cables, though. That's what I plan on doing when I build my dedicated HT in another year or so. If I were someone else building this mount, that's how I'd do it as well (running cables through the pipe). Also, I'm definitely not worried about going in the attic... I installed 3 permanent lights and a couple outlets up there because I'm in the attic so much...
- I didn't really like the idea of a single plate, because if you angle the projector enough one way, it'll angle the bolts and put pressure on the female threads on the projector. I'd rather have a nice, independent plate on it to start. Also, since it's plexiglas and only 1/2" from the PJ, you can't see it easily.
- Have you run into problems with the power cable being parallel to the signal cables for a stretch? I'm guessing not or you would've mentioned that -- it's something I'm somewhat concerned about. Also, I need to fit those 3xRG6 cables, a power cable, and an HDMI through my pipe. It is 1.5", but I'm pretty sure they won't all fit.
- EDIT: I remembered one more reason why I used two plates.. so I can attach a panamorphic lens hanging from the lower plate, which is fixed directly to the projector (and moves with it). When I end up getting a lens some day, I'll make a larger bottom plate that extends past the front of the projector.

Thanks for the comments.
post #10 of 98
Mine is a basic monkeyman mount, and I am doing the bad thing and running the power cable through the pipe too :( I dont seem to see any issues with it but it still makes me wonder.

Anyhow I have the following cables running through it:
vga cable for computer
hdmi for hdtv
component for dvd/ps2
power cable

A tight fit but just have to put them all in the correct order (largest connection to smallest) and all is good.

this pic is out of date (more cables/ceiling is now black!!!) but shows the size of the pipe.

yes I know the outlet isnt to code :(
post #11 of 98

Beautiful mount. How were able to radius the corners of the plexi?

post #12 of 98
Thread Starter 
Thanks Victor. I used a belt sander with somewhere around a 100 grit belt on it. I also used the belt sander along the edges, to make it slightly more rounded. Finally, I used a torch to gently melt it and get out the scratches. It's just difficult to do that without having it bubble, so you have to be very careful about that.
post #13 of 98
You can use a router with standard woodworking bits to work the edges of acrylic. To round the corners you'll need a template and a straight bit with a guide bearing.


I've also got a mount like this and was able to get a component, DVI, svideo, power, and a cat5 cable through the 1.5" pipe no problem...
post #14 of 98
Hey this mount looks familiar :) nice to see this mount idea is still running after all these years.
post #15 of 98
Is it DIY method that no need to mount the projector on the wall?
Because my apartment is rent, could not drill any holes on the wall :confused:
post #16 of 98
This is probably a really silly question, as I haven't bought my projector yet, but do they work upside down? I'm assuming there is a setting that allows you to pick upside down or right side up?


post #17 of 98
Thread Starter 
Not a silly question if you've never had a projector, Bry. Yes, there are menu settings to allow you to reverse the image so it displays normally when mounting the projector upside down (otherwise nobody would ceiling mount them) :)
post #18 of 98
Boy, am I pissed that I spent 150 bucks on my chief mount!!! This is awesome.

Great job!
post #19 of 98
I saw this LCD wall mount at BestBuy. It is pretty cheap and strong (holds 40 lbs). I think it can easily be modified with a plexiglass and ceiling mount it for your projector (similar to the original poster's design). It can also be tilted 30 degrees!

The advantage is that it is fairly cheap (a "partial" DIY), strong (holds 40 lbs), can be adjusted 30 degrees, is low profile (for those with low ceilings), and is widely available online or in-store at BustBuy Canada.

What do you think? Thanks.



https://www.sanus.com/images/VMF_Tilt.jpg https://www.sanus.com/images/VMF_VESA.jpg https://www.sanus.com/images/VMF_Virtual_Axis.jpg
post #20 of 98
I'm in the process of building one of these DIY mounts for a 4805 which I believe uses M4 screws. I don't have access to the ceiling, and I know I'm not going to hit a joists because right now I'm using mandarax's mount but the adjustment part is just driving me nuts, my cables are too heavy and dragging the PJs adjustment.

Can I use drywall screws to mount the flange to on the ceiling?
post #21 of 98
Thread Starter 
If you're going to ceiling mount your projector, you better do at least these two things:
- Screw into a joist (or support between two joists)
- Use big enough screws -- (hint: a drywall screw is not big enough)

You can bundle the cables together with a twist-tie and attach it to the ceiling, or to the pipe. Using my mount above, though, the cables could be hanging down to the ground and it wouldn't affect the adjustment of the projector.
post #22 of 98
Sorry, I meant more like drywall anchors, those 40lb rating or so each. I'm using two of them to hold my existing mandarax mount.
post #23 of 98
Finished mine yesterday, perfect! So easy to adjust :)
Thank you!
post #24 of 98
Thread Starter 
That would be more acceptable, of course. However, to each his own. I personally would use drywall anchor(s) to hold up a towel bar or plant, and avoid using them to hold up several thousand dollars worth of equipment. (Again, IMHO...)

Glad the mount worked well for you -- I especially like the adjustment capabilities on it as well.
post #25 of 98
Hey miltimj, a great thread!

I got an AE700 recently and may choose to mount it. As a tweaker and DIYer myself, I'd be going with your design. Also, I found this through the Minnesota Theater meets thread. Are you in Minneapolis or a suburb?

crackity -
I took a look at your site, and while I like your mount, I liked your room even better! I have roughly the same room size, and it's really what I had in mind for my place. I've got a couple questions:
1) What color is that paint? Manufacturer? I like the way the black works against it in the picture.
2) Can you describe your room lighting? It looks like fluorescent...
3) What about your absorber panels? Can you describe what you did there and how they are constructed?

post #26 of 98
Thread Starter 
Thanks, Choots.. I'm in a suburb on the opposite side -- New Brighton.

As far as my site, you got me a little confused now... which site are you referring to? (I'm not sure I linked to any other site I have from here, and the room you're describing doesn't describe mine, so I'm guessing (unfortunately) that my room is not as nice as you describe!)
post #27 of 98
Sorry miltimj, I was directing those comments at Crackity, who wrote post #10 and left a link to his HT pics.

I'm a new user...should I have put that in a separate post? What's the convention?
post #28 of 98

I am planning on getting a pj in the near future and am thinking of using your plans but i have a question....because these pj put off a lot of heat do you notice the first layer of plexiglas holding heat in near the pj....do you think drilling some holes in that first layer would benefit it...


post #29 of 98

What were the dimensions for the plexiglass panels for the 7700? I found a 18"x24" sheet at Home Depot for $13. I'm hoping I can talk them into cutting it for me. I'm a little worried about cutting it with a saw. I may try the score and snap method first.

post #30 of 98
Thread Starter 

My bad -- I now notice that you were directing those second set of comments to crackity.


From what I've seen, most projectors do not vent heat out the bottom of the projector, so the plexiglas isn't an issue. What PJ do you have (or will you be getting)? If you already have it, notice where it vents, and if not directly off the bottom, this mount won't be a problem.


The dimensions for each plexiglas sheet are approximately 14"x10" (bottom), and 12"x10" (top). Note that the top could be smaller, but the bigger it is, the more finely you can adjust the projector once it's mounted. That 18"x24" is plenty, and $13 seems like a decent price (that'd bring the total to a little less than $40 for all materials).

I cut the plexiglas with a metal/plastic cutting circular saw blade, on a radial arm saw. It melts into somewhat of a gooey mess, but once it's cut you just scrape the goo off with a putty knife, and use a belt sander to round the edges and it works great. For drilling the holes, I drilled it through, then moved the drill in a wide circular motion to make the hole slightly bigger and round the edges more. I've never tried the score and snap method - as long as it breaks off straight, you can always sand off any rough edges.

Also, keep the thin protective sheet on both sides while you're working with it to protect it. If you find some scuff marks on it, you can use a propane torch to gently heat the area and they will melt away. Be very careful though! And not just from burning yourself -- if you leave the torch on there even a second too long, the surface will bubble up and you won't be able to get rid of them. You just whisk the flame across it (without the two touching) and it will kind of melt after you've pulled it away. Practice on a spare junk piece first if you're curious... none of this part is necessary either -- only if you're a perfectionist. (You probably won't notice once it's mounted anyway)

Good luck, let me know if you have any more questions, and enjoy!
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