144" BOC screen - need paint help

Okay, I'm going big. I have a frame and the BOC. Please point me to the right mix. I'd like some reasonable gain 1.5-2.0. I have a Mits HC3800 projector and a 126" Draper M2500 2.5 gain now. The BOC actually does quite well with bright lamp mode, but I'm hoping to get something that will allow me to reduce to low lamp mode. So far I've read that the RS-MaxxMudd mix might be what I want?? Plus, I intend to roll a base coat on--what do you recommend? And spray the final coat(s) with a recommended Wagner CS from HD. Yeah, that seems crazy too--never done this before--but I'm willing to try (oh yeah, how much floating spray can I expect--e.g. how much cover up do I need to do so my wife won't clobber the idea?)

Thanks. I know all this is in other threads and I tried to wade through them, but my blood pressure just keeps rising.

Thanks for the input. I actually think it will be bright enough. I did a quick hook up last night over my 2.5 screen and put it into standard mode and the brightness was not bad. I just need a little more gain and I will be all set I think. Check out carlofet.com or BOC.

I reviewed your DIY Screen Comparison link. Wow, nice job and eye-opener. I'm going to have to rethink this whole thing. I'm curious as to what drove you to put this link together? Perhaps you are on the same search for screen paradise like I am. ;o).

I went to your homepage link and see that you tried making a painted BOC screen. How did that work out?

Good to know--thanks!!

Okay, I bought all the ingredients for RS-MaxxMudd-LL yesterday. I'm putting together an aluminum frame now with some BOC cloth. I was going to spray the paint on, but decided to paint it on. I realize the cloth is going to stretch, so I have to deal with that, but if I solve that problem I know others would be grateful. I also painted for a living when going through college years ago and know how to avoid roller marks, so we'll see. I will take pics along the way--wish me luck. If this doesn't work out--well it will be a fun ride anyway. My wife is furious--"we don't need another stinking screen, what's wrong with the one we have?" It's too small I tell her--she just doesn't get it.

"Damn it Jim, I'm a doctor not an engineer!"

Okay, I will roll the primer and spray the final--I've come this far, what the heck... And thanks guys, I know you're right...

Okay, put the screen frame together yesterday and stretched BOC around it. Man this thing is huge: 128" x 72" or 147" diag. Was shooting for 144" but got away from me. Looked at it this morning and ugh--lots of creases and wrinkles. Sooo...I got out the steam iron and ironed it lightly from the back with puffs of steam--worked to get most wrinkles out. Then turned it good side up and lightly blew steam over deep creases and lightly ironed them--worked perfectly! Did a retighten of the material, and now setting up to do the base coats--going to roll on...ahh, my wife is not talking to me--she doesn't want a bigger screen.

Pics coming soon...

Yoohoo, put the first base coat on and 4 hours later (with my son's help) dragged the screen out of the back furnace room and propped it in front of the old 2+ gain draper M2500 126" screen. We were dumbfounded. First we agreed, wholy crap this is huge; then a big smile came over my face as the projector turned on and I zoomed to the big screen. All my son could say was, " Dad, I think it's as bright as the other screen." And I had to somewhat agree. That first coat of Behr Flat Enamel (has a slight sheen), is fantastic. I'm almost wondering if I need to go with the final RS-MaxxMudd-LL (but you know I will). I won't have pics until tomorrow, bu dang this baby is beautiful. Oh yeah, I'm shooting a Mits HC3800 on it on low lamp mode and it's bright enough (at least for now, the lamp is almost new).

All that said, wow, painting that first coat was definitely an experience. First, I used a sponge roller (read somewhere that it works better--NOT!). The sponge would not put paint on the BOC, so I quickly exchanged it for a 3/8" nap teflon and it worked, but not without a lot of back and forth rolling, then one final sweep up (always keep the last roll in the same nap and roller direction; I learned from years of painting to put myself through school). Second coat goes on tomorrow.

Oh yeah, this is bizarre. I was going to buy a Wagner sprayer and was looking in the garage for some paint rollers and found that I actually bought a sprayer two years ago as part of Wagner Deckmate kit. I used the deck tool, but ignored the spayer--and there it was sitting abandoned in the corner--I hugged it.

I'm still trying to wipe the smile off my face from watching the initial screen in action . My wife is going to love this...well I can hope...

About 16ft. It takes a complete zoom in to fill the screen--does it nicely and wow it's even bright. I'm so excited (and relieved) that even the 1.0 UPW paint is giving me a heck of screen already. I'm also surpised that with just one coat, I see no roller marks. I'm giving another coat tomorrow, then going out of town until next Monday--and will spray then--can't wait!! I honestly didn't think this was going to work out as well as it's progressing...

Here's the screen with BOC stretched over an aluminum frame--it's huge!



Here's half the screen painted with Behr UPW Flat Enamel.Notice how grey the BOC is against the enamel. Sure don't see this until you paint it.



Here's the first coat on. The flash is trying to counteract the flourescent light so the colors look off, but this baby is white!. Did a screen test with the projector and it's awesome just with this base coat on.

Doing a second coat today. More to come early next week. I'm going out of town tomorrow.

Finally getting around to spraying the final coats on the screen. I actually rolled the base coat and two coats of LL over it to see what it will do. It's definitely about 1.4 gain on center (I held a 1.0 gain swatch to it and it's definitely brighter), but like all high-gain screens the gain drops off dramatically toward the edges. I'll need somewhere inbetween low and standard lumens on this thing as low seems two low and standard has some blown-out whites, so I'll have to compensate for that.

That said, I did my first spray coat and it was not as easy as I hoped. The spray pattern is only about 8 inches wide so I had to be very, very even to fill the gaps, and I also found slowing down the movement of the sprayer helped. I'm sure my mixture is just too thick, so for the next round, I'm going to thin a bit. And I would lose my depth perception sometimes looking at the plain surface and that didn't help either.

Interesting is when I mixed the batch, it definitely had a grey appearance, but left overnight in the morning, it looked much whiter to me. Looks like the silver disappears into the mix when left for 8 hours. Probably wise not to spray the mixture until the next day to let the molecules play with each other a bit.

Thanks for the insight pb_. I've done two initial sprays, now going for the final.

Oh yeah, and this for the "dumb and dumber" in me. I cleaned the paint gun nozzle, tube and jar per mississippi's video, BUT forgot to take the nozzle assembly off the sprayer when I ran water through it--yup, I filled up the blower compartment with water. When I realized what I had done, complete panic set in, so I layed out paper towel on the kitchen table and spent the next hour taking it apart, drying out what I could and using a hair dryer to force air through the motor assembly. Well, I plugged it in and it WORKS! again. I thought for sure the motor was fried, but not. So on to the final coats I go...

I think I found 10" to be right and overlapped as well as I could, but the surface sure doesn't look wet. I went over it several times to make sure there weren't any tire tracks. We'll see when tomorrow when I give it a go with the projector.


It's probably an illusion, since the Behr UPW is so white when you first mix it in, it makes the grey more obvious. The screen looks much whiter than I expected unless you compare to white BOC, then you can see the grey--as per the picture above.

Woohoo, I'm done! I looked sideways on the screen and there were still some vague sprayed high/low lustre tracks so I was worried about that when putting first light on to it. Also, the screen picked up some dust blobs here and there so I carefully plucked those off.

Handling the screen by myself was a tall order. I had to maneuver it out from behind and around a furnace through a door. Halfway through the door, I noticed I caught a protuding handle on the furnace and it was poking a dent in the canvas--aaaeeeeiiii. I recovered from that and the "dent" faded out and back to a flat surface--yay! I then struggled to move it through the rec room and lift it unto a box over the old screen. (I had done this twice already with pre-finish coats, but this time I had to be super careful). Now, startup my Mits HC3800, zoom to an image to fill the screen and focus. I had tears in my eyes. The image was pristine. Very even across the screen, no hot or cold spots. Colors are fantastic along with contrast and enough light in low mode. I watched several hours of TV and a DVD movie, then went to bed--happy!!

Here's a summary of what took place to get here.

1. Put together 128"x72" aluminum square tube frame.
2. Stretch BOC over it.
3. Rolled two coats of Behr 1850 UPW flat enamel on the BOC.
4. Test image on screen so far--wow, very nice even with just the Behr.
5. Mixed a batch of RS-MM-LL, let sit overnight.
6. Rolled on two coats of RS-MM-LL over the Behr. Let first coat dry over night.
6. Checked the image on projector. Could see some hot/cold tracks due to rolling. Screen had a lot of particle grain to it. Definitely higher gain than one. I compared to a 1.0 gain material and the 2+ gain screen already in place, and I would say the screen was 1.4+. Overall, the screen had a slight sheen to it though, but the image seemed muddy to me (not sure how else to describe it) --hmm, I was worried from this point on.
7. Several days later, whipped up another batch of RS-MM-LL and let sit overnight.
8. Next morning, sprayed on several light duster coats followed by several slow overlapping coats. Getting used to sprayer. Paint seems too thick. Lots of alternating wet/dry tracks on the screen. Worry again. Cleaned spray nozzle and accidentally got water inside spray blower--ugh!! Cleaned that out, thinned paint and went back to spraying final coats. Gave it several even overlapping coats at 10" with the thinner paint mixture and that did the trick. Then did several duster passes per Mississippi's directions.

Just a pre-conclusion note: I have had projectors since 1995 (yes, I started with CRTs, a Benq 8700, an Optoma HD70, an Optoma HD20--for several days, and now a Mits 3800). I also have had various screens, including 1.0 gain Stewart, 1.5 gain Dalite Silver Matte, 2.5 gain Dalite High Power, and 2+ gain Draper M2500. Does this replace all those screens without trepidation--yes--except for the Dalite High Power--not much beats that--but it's not a good screen for ceiling mounted projectors--and I couldn't afford it anyway.

My conclusions--screen pics to follow later today if possible:

* Rolled Behr UPW Flat enamel over BOC is pretty good and many would like it as is. Could not see roller marks.
* Rolled RS-MM-LL gives a different image impression than sprayed. I did not like it rolled.
* Rolled RS-MM-LL appears to have slightly more gain than sprayed. I would say the final sprayed image has about 1.2 gain vs. 1.4 of the rolled, but overall much better image quality (yeah, you guys keep telling us that, but I had to prove for myself). It could be the final duster coats that reduce sheen causes the gain to go down.
* With RS-MM-LL a large screen (145"--my final bordered image) can handle a projector in low mode (Mits is supposed to be between 500-600 lumens in low mode).
* I see no color tweaking required. There is no individual color push that I could see-whites are white. Maybe needs some contrast/brightness tweaking, but that's it. Blacks are very nice, but they were also nice on my 126" Draper M2500 2+ gain, which this will be replacing.
* Sprayed screen is very 3D. Rolled version, not so much. I think many DIYers would like hearing that conclusion as the question seems to come up frequently on this board.

Here are the pics I promised. All shot with a Lumix ZS3. I don't have any velvet board around the edge of the screen yet, so you can see what ambient light does to the blank edges. Also, colors are much better than the camera shows and it also introduced some image noise--take that into consideration.

This is a shot of the first coat of Behr 1850 UPW Flat Enamel on the BOC --not bad!


First image on new RS-MaxxMudd-LL screen. Room is completely dark.


Okay, I open the two windows in back to get some ambient light--room is over 50 feet long so take that into consideration.


Here's the same shot with window light from behind--hey very watchable.



Closed windows with dark shades. Room is cave-like. Note, the snow looks blue and that is correct due to bright sun and blue sky reflection.


I turned on all the overhead fluorescent lights. Washed out, but still watchable.


Here's same shot straight on with all lights on.


Now completely dark again.


Same shot at 45 degree off center--still pretty bright.


Here's a telltale shot of an almost white screen. Note the swatch of 1.0 gain material hanging from a piece of duct tape. It looks slightly darker. Screen is about 1.2 gain, I'm guessing. Note the slight hot spot in the general center of the screen. I do not see this, but the camera does.


Here's same image shot at 45 degrees. Note swatch now brighter. Typical of a gain screen. Off axis loss of gain. The image looks slightly blue, but that's the camera. I did not see that. The moire pattern on the left side of the screen is due to the screen door of the dlp and my camera's reaction to it--I do not see that on screen.


Here's what Mits HC3800 owners want to see. This pic is in low lamp mode (between 500-600 lumens) and really looks like a saw it.


Same image with HC3800 in standard lamp mode (700-800 lumens I think). Note the kick in brightness, but not really needed. Made my day.

Bump--I added pics.