My DIY horizontal masking system

I decided to post a thread on this for others to use. I built a horizontal masking system for my 106" fixed frame screen. First of all the screen frame is an Elunevision frame. I switched the Elunevision fabric to Center Stage XD material. You can see the thread here: www.avsforum.com/avs-vb/showthread.php?t=1180610&highlight=convert+elunevision

My masking system consists of the following items:
1. 7 ply fiberglass faced plywood. (Had this at the shop so I used it)
2. Two pieces of flat stock sheet metal. (Had this at the shop. I think it is 24gauge.)
3. Flat stock of sheet metal. (Had this at the shop. I think it is 28 gauge.)
4. 12' of 1/16" air craft cable. TSC
5. Triple black velvet. SY Fabrics
6. Small turnbuckles for cable length adjustment. TSC
7. Four 1/16" cable clamps. TSC
8. Two oval chain links to connect turnbuckles to masking system. TSC
9. Two screw hooks to hang pulleys. TSC
10. Four heavy duty draw slides. Lowes www.lowes.com/lowes/lkn?action=productDetail&productId=50184-130-8400PR 18&lpage=none
11. Two pieces of 12" long 1/2"x1/2" aluminum angle. (Had this at the shop.)
12. Sheet metal screws, wood screws, wood glue and 3M Super 77 spray adhesive. (Had these materials at the shop.)

I made four sheet metal angles (24 gauge) 3/4"x2"x8" long for brackets. These were fastened vertically to the back of the screen frame, about 1-1/4" in from the outside edge of the screen frame. I attached the draw slides to these brackets. I made four sheet metal (28 gauge) U-brackets to wrap around the end of the screen frame. These brackets have a 3/4" leg coming off of the "U" so that I could connect the other half of the draw slide the the "U" bracket. The "U"-brackets are 6" long and the legs are 3" (face) 2-3/8" (side) 1-1/4" (return at back) and 3/4" leg to attach to draw slide. With the brackets and draw slides in place I now have four pieces of flat sheet metal (face of "U"-bracket 6" high x 3" wide) in front of my screen frame to attach the masking panels. These brackets are free to move (18" total) up and down the vertical face of my screen frame.

For the masking panels I cut three 8" wide strips from the plywood. The third strip is need so that I can make two panels 98-3/8" long. I beveled the top edge so that when the panels are in place there is a slope on the edge towards the screen. I used wood glue and biscuit joints to make the panels the length I needed. Next I simply covered the panels with Triple Black Velvet.

Since the distance from the back of the masking panel to my screen is about 1-1/4" I needed a way to extend the masking back to the screen. For this I made two sheet metal angles (24 gauge) 91-1/2" long with 1-1/8" leg and a 2" leg. inside to inside of my screen frame is 91-3/4" so I have 1/8" clearance on each side. These sheet metal angles serve two purposes. One is to extend the masking to the screen and the other is to keep the masking panels from ever bowing. Angle is attached to the masking panel every 10" with wood screws. The angle sticks up above the masking panel 1/8".

To cover the angles I cut two strips of velvet 4" wide and 94" long. I sandwiched the velvet between the masking panel and the sheet metal angle. The ends of the velvet were folded back and tucked under the ends of the angle. This created an edge that extended about 3/16" past the end of the angle. This was done to fill the 1/8" gap between the masking and the inside edge of my frame. I then sprayed the inside of the angle with Super 77 and wrapped the velvet around the angle.

I removed the sheet metal "U"-brackets from the screen. They slide off when you press a release button on the draw slide. I then screwed the brackets to the back (end) of the masking panels. Then I simply slid the brackets back onto the draw slides. With the masking panels fully open (1.78) the 91-1/2" long sheet metal angle rests against the inside edge of my screen.

The cable system is very simple and used by others here. I attached the 12" long x 1/2" x 1/2" aluminum angles to the back of the "U"-brackets on the top mask so that I would have a cable attachment point six inches below the masking panel. This allowed me to mount the two pulleys lower so that they are behind the screen rather than above the screen. I installed the two pulleys so that the top of the pulley is about 1-1/2" below the top of the screen. I connected a turnbuckle to the bottom mask and ran the cable up to the pulley and then down to the bottom of the 1/2" x 1/2" aluminum angle connected to the "U"-bracket. I did the same on the other side. I adjusted the turnbuckles so that the masking when fully open has the 91-1/2" sheet metal angle resting against the inside edge of my screen. Now when one panel is moved the other panel moves the same amount in the opposite direction.

I did not take pictures during the install, but here are pictures of the masking panels in place.

1.78 screen aspect ratio
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2.40 screen aspect ratio
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Close up of the masking panel. You can see the slope on the plywood edge and it shows the angle raised up 1/8" above the edge of the plywood masking panel.
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Pictures were taken using hand held camera and flash. That is why you can see the aluminum driver of the sub. Very pleased with the results. It seems to be a lot more emersive when watching movies with out the gray bars. The hardware cost me $24.00 from TSC. The Velvet $29.50 from SY Fabrics and the drawer slides $24.00 from Lowe's. Since I had all of the other materials the total cost was $77.50.

Here is a picture of the cable system. Picture is of the top right hand side. Cable is connected to a 1" x 1" aluminum angle. The angle is used to lower the connection point to the top masking. This allows me to locate the pulley below the top of the screen. Aluminum angle is connected to the sheet metal "U"-bracket. Sheet metal "U"-bracket is connected to the masking in front of the screen and one side of the drawer slide in the back. Other side of drawer slide is connected to sheet metal angle fastened to the back of the screen. You can see the sheet metal angle right below the drawer slide. Every thing except "U"-bracket is located behind the screen in the 3-1/4" wide vertical width of the screen frame. I still need to paint the "U"-bracket, but you can't see the "U"-bracket when viewing the screen. The masking panel hides it.
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Currently you have to align both sides of my top masking panel with the edge of the gray bar. Not a big deal, only takes me about 5 seconds to slide and align masking in place, but I have come up with a cheap, easy solution. My plan is to purchase two or three stamped steel pillow block bearings and slide them over a 1/2" pipe. Mount these horizontally on the wall right below the blocking in the photo above. Then just wrap (2 wraps) the 1/16" cables around each end of the pipe. With that in place when you pull down one side of the top panel it will rotate the pipe and move the other side the exact same amount. It will not make a difference in the functionality of my masking, but it more professional in its operation.

I took another close up of the lower masking panel. To get the image to show up I had to do the following: Turn the three 65 watt floods right above screen on full, open blinds and curtains on the one window and use the flash on the camera. Even with all of that you still could not see anything except black, so I over exposed the picture and ajusted the contrast and shadow detail. Now you can see the masking panel.
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Picture of masking with lights on, window blinds and shades open and camera flash.
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Same picture with exposure set to 100, contrast 0 and shadow detail 100. You can finally see the masking. Masking set to 2.40.
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I installed (like I talked about in post #3) a couple pillow block bearings and a piece of 1/2" EMT horizontally behind the screen. The EMT was installed right below the blocking shown in post #2. Each cable makes two wraps around the EMT. This way when you pull down on the masking the cable rotates the EMT and moves the other side the same amount. Now I can reach up with one hand and slide the masking into position without having to align each side.

Picture showing 1/2" EMT and the two 1/2" pillow block bearings.
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Total cost of masking system is right at $112.00

yes it is working well. Before I added the pillow block bearings and shaft, you had to level one mask with the gray bar. Worked well, but it did not look as professional (when setting the mask) as I wanted. Now you can grab one mask at one end and both masks stay level when moving into position. Does make a little noise when moving into position, but what can I expect for a $112 dollar adjustable masking system. I know that I can't buy a horizontal masking screen anywhere near as good as this for $2,000.

I changed out my center speaker (JTR T8) so while I had the frame down I took a picture showing the end of the screen. The pic shows the end of the velvet covered masking panel, the sheet metal "U" bracket that fastens to the back of the panel and goes to the draw slide on the back side of the projection screen frame.
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Here is a picture showing the back.
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It is the first paragraph following the materials list in the first post. I made a sheet metal angle that was 8" long. One leg is 3/4" wide and the other leg is 2" wide. I fastened the 3/4" leg to the back of the screen frame. The 2" leg sticks out from the back of the screen frame at a right angle. I mounted one side of the drawer slide to this angle. The other side of the drawer slide mounted to the returned end of the "U" bracket. The "U" bracket wraps around the end of the projection screen.

The "U" bracket is fastened to the back side of the masking panel. Since the total width of my projection screen with frame is over 8' wide I had to use two pieces of plywood to make a masking panel over 8' in length. I used biscuit joints, but you could just screw a flat piece of sheet metal to the back side of the masking panel joint to hold the two pieces together. Don't worry that the joint is flimsy. The sheet metal angle (91-3/4" in my case) that is attached to the back of the masking panel will make it rigid. This angle is 91-3/4" long because my 106" diagonal screen is 92" wide. This angle has to fit between the projector screen frame. You can see this velvet covered angle in the picture of post number 4. This angle is what carries the leading edge of the masking panel to the screen. The velvet is attached to the angle using spray adhesive.


That completes the masking panels. The masking cable system is simple. I have a cable that attaches to the bottom panel and goes to a pulley above the bottom of the upper panel and then down to the upper panel. To make it so that the pulley does not show and can be hidden behind the upper masking panel rather than above it I installed a 1/2" x 1/2" x 12" angle to the "U" bracket of the upper panel. This gave me a cable connection point several inches below the bottom of the upper masking panel. This allows the top of the upper masking panel to move higher than the pulley so that the pulley is always hidden.

I then installed a piece of 1/2" EMT conduit in a couple of pillow block bearings. I wrapped the cable around the conduit two wraps. Keep in mind there is a cable on each end of the screen. When a masking panel is moved the cable moves the same amount. Since the cables are wrapped around the 1/2" EMT it moves the other side the same amount and the panels stay level.

On my system, the easiest way to automate it would be with a linear actuator. Just need an actuator with enough throw to move the panels enough to cover all the movie aspect ratios. A actuator with 8" of throw would work. You attach one end to a panel and the other end to the projection frame.

I used 1/2" EMT and I believe that I used 1/2" pillow block bearings. Just measure the OD of the rod or pipe that you use and get a pillow block bearing that is slightly larger. I think these are the pillow block bearings that I used. http://www.thebigbearingstore.com/se...-Pillow/Detail

Added
I have a cable on each end. The cable is located right behind the vertical end members of the screen frame. The cable is attached to the "U" bracket that attaches to the bottom masking panel. Attachment is by a small turnbuckle. The cable them wraps twice around the shaft and then up to a pulley and then back down to a small 1" x 1" x 12" angle that is attached to the bottom of the upper "U" bracket that attaches to the upper masking panel. This link shows the upper pulley and the aluminum 1" x 1" x 12" angle that is attached to the bottom of the "U" bracket attached to the upper masking panel. http://www.avsforum.com/avs-vb/showt...4#post17358644 The purpose of the angle is to give an attachment point that is lower than the upper panel. That allows you to locate the upper pulley below the top of the upper masking panel so that it does not show.

This link shows the end of the upper masking panel, the "U" bracket that goes around the end of the screen connecting the masking panel to the draw slide and the 1" x 1" x 12" aluminum angle connected to the "U" bracket. http://www.avsforum.com/avs-vb/showt...4#post18457424