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Solid Torus and masking Idea

 
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musty



Joined: 01 Oct 2006
Posts: 58
Location: Way Down Under

Posted: Tue Oct 03, 2006 8:39 am    Post subject: Solid Torus and masking Idea

I have been reading alot about torus screens and understand the benefits that would accompany one,so I have some Ideas of my own,whether it will work or not is why I am asking you guys for opinions.

A solid torus can be achieved by

1)first building a support frame with the appropriate radius for curves routed into the frame.
2)Lay a thick mesh into the grooves and allow gravity to sag the mesh appropriately.
3)Spray a resin that will solidify to form a rigid base.
4)san the resin once dried to form a smooth finish ready for either a pearlescent paint or anything that will give you the gain you require.

Masking....
Once the solid frame is formed and torus complete,by attaching a thin strip of metal on the back of the screen and strips of magnet embedded in black velvet on the front of the torus,one will be able to gently slide and move masking as required, hence providing perfect masking with no gaps.

This is my Idea and I know I can build it but there are two things I am not sure of and thats radius of curvature and the best material/paint for a crt.

Please feel free to comment and critisize or even tell me if I am crazy and waisting my time.
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Jeremy112



Joined: 28 Sep 2006
Posts: 2649
Location: Fond du Lac, WI

Posted: Tue Oct 03, 2006 1:01 pm    Post subject:

Your crazy and your wasting your time!

Just kidding, it all sounds good so far, Im new to all this home theater, seeing as the only thing I have to use as a projector is my cheap proxima lcd projector. But good luck!

JEremy
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garyfritz



Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO

Posted: Tue Oct 03, 2006 6:07 pm    Post subject:

Letting gravity sag your mesh means you don't have much control over your curvature, other than the radii on the support frame. You might come out just fine, or not, depending on how much slack you put on the mesh.

The radii control the focal length of the torus and determine the gain, viewing area, etc. I wouldn't leave it to chance.
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GEBrown



Joined: 08 Mar 2006
Posts: 729
Location: Denver

Posted: Tue Oct 03, 2006 7:48 pm    Post subject: Re: Solid Torus and masking Idea

musty wrote:
. . .
This is my Idea and I know I can build it but there are two things I am not sure of and thats radius of curvature and the best material/paint for a crt.
. . . .


I save this from an older thread somewhere - not sure if it is considered the best or not - but it should help.

Gary



TorusSpreadsheet.zip
 Description:
This should help you with the radii.

Download
 Filename:  TorusSpreadsheet.zip
 Filesize:  32.46 KB
 Downloaded:  796 Time(s)

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musty



Joined: 01 Oct 2006
Posts: 58
Location: Way Down Under

Posted: Tue Oct 03, 2006 8:14 pm    Post subject:

GE Brown

Thanks for that,its exactly what I was looking for.

Now all I need is the correct gain material for surface.
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garyfritz



Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO

Posted: Tue Oct 03, 2006 8:53 pm    Post subject:

Vutec PearlBrite seems to be the big favorite for tori. Gain is supposed to be 3.1.
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AnalogRocks
Forum Moderator


Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G

Posted: Wed Oct 04, 2006 1:32 pm    Post subject:

Do these screens hot spot?

A while back I was looking for a 72 inch 4:3 for my computer desk and someone sugested a tarus. Someone else mentioned it would hot spot.

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garyfritz



Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO

Posted: Wed Oct 04, 2006 2:55 pm    Post subject:

The whole idea behind a torus is to *eliminate* the hotspot by bending the screen. This spreads the hotspot out. Essentially the entire SCREEN becomes one giant hotspot, giving very high gain.

A 72" screen for your *computer desk* ?? You must have a big desk!!
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AnalogRocks
Forum Moderator


Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G

Posted: Thu Oct 05, 2006 4:11 am    Post subject:

Well once you get the sony 21 inch monitor on there where do you go from there?
I know the 24inch CRT but I can't find one locally so I thought a PJ and a 72inch screen running 1600 x 1200 would make for a nice monitor. Maybe an NEC XG 85 or something like that.

So I like the idea of spreading out the hot spot. What's the avaerage gain of one of these beasties?

I remember someone sasying they had an old SONY screen with gain around 15 or something. BUT they were to far away for me to get it.

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CRT.

HD done right!
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mack1



Joined: 21 Mar 2006
Posts: 494
Location: SARNIA

Posted: Fri Nov 24, 2006 2:16 am    Post subject:

My torus is 6'x8' with a gain of about 3.2.I'm using the pearlbright material and it looks great--also should note that with a torus you can turn down your contrast ratio and save your tubes--I'm running at about 45
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Crabman



Joined: 17 Mar 2006
Posts: 197
Location: North West NC

Posted: Sat Dec 23, 2006 4:29 pm    Post subject:

musty wrote:
GE Brown

Thanks for that,its exactly what I was looking for.

Now all I need is the correct gain material for surface.


Beware, that calculator while a good one, does not correct for projector position which is VERY important. You have to factor in the position of the light source!

Clay

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Maybe it's a snake. Earl, do snakes have fur?

-Randy
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