DIY Screen, 4:3 and 16:9 masking

[AMc]

Hi Guys,

Finally got my first PJ - Philips Bogart (1024x769, 800 Lumens 1800:1 contrast DLP)

I've got an IKEA blind and mounted on a temporary arrangement of a batten and a counter weight. It sits on top of the centre on the TV and rolls down in front. The TV and stand look like this (blind not pictured)


I thought that my roller arrangement would work for a while and would have the advantage that I could make a 4:3 screen or a 16:9 screen depending on what I was watching. Unfortunately it's hard to get the fabric to roll and unroll evenly so I'm thinking on canabalising the blind to build a fixed screen to go in front of the TV when I need it.

I've checked various threads about DIY screens and I'm fairly happy with how to build it from a timber frame.

1 - Would you recommend making the screen oversize to allow for a black border or simply make the screen the exact size?

2 - I'm thinking of using an open frame (180cm x 135cm) and having a 4:3 ratio on one side and masking the other down to 16:9 (180cm x 101cm) with black cloth. One side of the cloth is less suitable than the other for projecting which I'm prepared to live with for now - any other obvious flaws?

3 - I think in the end I'll buy a 4:3 portable screen - am I wasting my time here and I should bite (another) bullet and spend £150+ on something now?

Any constructive comments would be appreciated. Thanks!

[AMc]

More Q's
- What dimensions of timber will I need to have enough rigidity to stretch the fabric?
- Any recommendations for what to buy that won't warp?

[Iaind]

Andy,

My screen is a canablised (sp?) ikea blackout blind. I wanted to buy the 2 metre wide screen but they wouldn't have them in stock for another 7 weeks, so I bought a 1.5m wide one. Initially I was going to mount it horizontally and by a somewhat Heath Robinsonish gadget stretch it tight across the wall.

Didn't work! So I bought some timber from Bees and Ques and created a frame approximately 6ft wide by 4ft high. I used triangle corner braces for additional strength and (hopefully) making the screen square. Also put in a central strut for added strength/stop middle sagging. This sits on the wall by means of 2 offcuts of wood screwed to the wall and the screen then just sits on top of them - obviously these are hidden by the screen itself.

Trimmed the screen all round with black velvet (1½ metres x 1m wide - £24'ish). This was cut into 25cm x 1m strips which were then attatched to the screen. I used extra strong (allegedly) double sided carpet tape, but this is not that strong so I might reattatch using copydex. The lower border is 30cm deep as a 'contrast'.

I used 270mm x 150mm (approx) wood and it was fine - the only thing to watch is that the wood isn't warped or twisted. It came in packs of either 4 or 6 (can't remember which) for about £5.00 (sorry these are so vague but I can't remember my name some times so what I did last week is virtually impossible). The blind was cut off the roller and stretched over the frame, attatched using both staples and small panel nails that I had left over from building some units.

Screen looks okay (but not stunning) and although there are a few creases in it, they don't really show up when watching a film.

If I did it again I would try and make the fabric a bit tighter and get a longer piece of velvet and hem it properly (well, okay, not me but my mum!). Overall though, I am very pleased with my DIY screen as (velvet excluded as I still have loads left) it only cost me about £20!

I don't have a digital camera to take some photos, but I will see if I can borrow one and get some shots up onto this site.

Regards
Iain

[AMc]

Hi Iain,

Thanks very much for the information - Are you sure you really mean 270mm x 150mm - that's 10" x 6"? Maybe 27mm x 15mm or 1" x 0.6"?

One of the things that really annoyed me when chosing my projector was everyone quoting throw in metres and screen sizes in inches. I mentally work in metric so I have real problems visualising a 6' screen or a 100" diagonal.

I had to buy the 160cm blind because they had no 200cm ones in Thurrock either I would have waited but my partner would have killed me if I suggested we come back again after trudging all the way out there specially Looks like it doesn't matter in the end anyway.

(If I'm right about the decimal place) I think I have some spare timber in the basement I can use. If push comes to shove I can always dismantle it and rebuild with stronger wood.

I'll check out the local fabric shops for velvet and get a length as long as the screen if I can.

Which side of the blind did you use, the brigher white or the slightly duller one?

Cheers!

AMc

P.S. It's spelt "cannibalised" according to http://dictionary.reference.com/search?q=canabalise.

[AMc]

FWIW I built my screen on Saturday...

I decided to risk using some 33mm x 15mm wood that I had kicking around - I figured I can always build a sturdier frame and reuse the fabric if this warps.
I used mitres and L brackets in the corners to hold in place. I didn't have a large enough flat area to do the woodwork in, that lead to a fair bit of swearing trying to get the thing square - if you can do all the work on the floor!

I constructed a 4:3 frame that was 180cm x 135cm + 3.3cm all round (the width of the timber) intending to use that as a slim black border. After the baby was in bed and my partner had gone out I dismantled the blind and laid it out in the lounge.
Then I brought the frame up from the basement and discovered if it was a few centimetres bigger it wouldn't have gone up the stairs
At this point I discovered that the blind fabric wasn't actually 200cm long, more like 185cm . I unpicked the wooden bar at the bottom of the blind but the holes that left behind looked like they'd make great perforations when I tried to tension the fabric so time to rethink.
Back to the basement and I cut down the frame to 175cm x 131.25cm - well somewhere near that. Then I relayed the frame over the fabric. Following these instructions as best I could http://www.rexart.com/stretching.html. I gently tensioned the fabric holding it in place with brass drawing pins in the back of the frame.
After about 15 minutes of work I had the fabric fairly taut and I trimmed off the excess fabric from the back - it cuts really easily with a craft knife. I had intended to staple the fabric in place after getting it taut with drawing pins, but they were holding and I figured I might want to restretch it later.
I put the screen up and noticed that there are some minor wrinkles in the middle of the long sides at the top and bottom. I missed the part about temporarily tacking the corners once you have the first pins in the centre of the long and short sides -this may well have been the problem.

I added another battern in the centre cut a couple of millimetres longer than the gap so it tensions the frame. It also adds a handy place to hold the frame and somewhere for the frame to rest on the front of the TV.

I powered up the PJ and the wrinkles aren't noticeable. If I could I would redo the stretching with two people. I'll probably buy a proper collapsable screen at some point in the future but for £20 it's very hard to beat!

I got the PJ mounted on the wall yesterday, inverted and a couple of metres up the wall on a speaker bracket. I need to align it a little more carefully as the 4:3 image is about 2 inches too low, but the image fills the frame completely with virtually no overspill.

We watched DareDevil last night and I was very pleased indeed - I thought the film was a bit poor (impluse buy) but the big screen at home takes some beating!

[Iaind]

andy,

You had exactly the same issues as me with wrinkles (the screen, not mine). Like you, if I could I would restretch the canvas with two people. And getting the thing square ---- all comments deleted ----- !

It is impressive though, all the mates I have had round for a viewing are well impressed.

Iain

[AMc]

So far only me and my partner have been treated to the full 'Odeon in the lounge' experience. I'm looking forward to showing off to some friends and family soon!
I also need to do some work on light control in the lounge so I can start a film before 8.30pm.