CurtPalme.com Home Theater Forum

donaldk · Joined: 17 Jun 2008 Posts: 308

betel · Posted: Sun Dec 05, 2010 11:51 pm Post subject:

DAMN!

Just got my geometry complete and was removing the marker tape from the screen. You know that special blue tape we like to use. When I peeled off the piece marking the center, I'll be damn if it didn't pull the paint off the screen. Crap! The down side to these screens are they are fragile. I should be able to repair ir though. The finish appears to be an aluminized paint. Anyone have any idea what is best to use. On the plus side the image quality is fantastic. I'd have to say the geometry was a bit easier to dial in than the flat screen. I haven't attempted a color calibration yet but it looks very good as it is. That missing paint is very annoying though.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I thought it was a translucent material over aluminum.

betel · Posted: Mon Dec 06, 2010 3:53 am Post subject:

Tom.W · Joined: 09 Mar 2006 Posts: 6635

In the future avoid the blue painters tape as it has a rather strong adhesive. Use Scotch 285 artist tape.

http://www.3m.com/product/information/Scotch-Artist-Tape.html

betel · Posted: Mon Dec 06, 2010 7:02 pm Post subject:

Spoke to a Vutec rep. today about the screen coating. He wasn't very much help. He did tell me the surface is a laminated material and is similar to their Silverstar product. It would be nice if I could reproduce the same finish but probably won't be able to do that. I think my best option is to apply an aluminized spray coating. Perhaps with a clear poly on top. I'll definitely experiment on some cardboard or something before I attempt it on the screen.

Spanky, I've read a few threads about torus screens that you contributed to. Do you know what is the material the DIYers use when they make a torus using a fan to form the shape. Might be able to laminate that onto the surface. BTW: I don't have any interest in making a torus where I have to turn on a fan to pull my screen in. That's a bit too hokey for me.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

You might try some of this paint. Looks a bit pricey though...

http://www.gooscreen.com/

A bit more reasonable.

http://www.screenpaintsupply.com/

betel · Posted: Mon Dec 06, 2010 10:01 pm Post subject:

"Looks a bit pricey though... "
Tom, that is a bit of an understatement.

The "Ultra Silver 3D" is $180 for 500mL. That works out to be $1,363 per gallon. Must be made out of real silver.

My guess it is a commercially repackaged product that is grossely upcharged.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I don't keep up with Ken, but I believe he was making his own product.

As for the screen, I won't chastise you for putting tape on it. I just assumed you could tell that it was a delicate surface. I am not sure if there is a great solution, because it will be difficult to duplicate the gain and the sheen. I used my coatings in my experiments, but that was over an aluminized surface. Take a picture.

The DIY Torus uses Vutec Pearl Brite. Unfortunately, it is only two gain or so. If you really want to go that route, then it would be best to duplicate that screen. Basically, you would have to adhere some aluminized mylar to the surface and then spray it with an opaque coating.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Perhaps this might work...

http://www.hubindustrialsupply.com/default.aspx?page=item%20detail&itemcode=065-017-013

Or aluminum paint.

http://www.rustrustler.com/

betel · Posted: Tue Dec 07, 2010 12:08 am Post subject:

The rustrustler looks promising. It could get expensive to try different samples trying to find the best one though. Surely DIYers have figured out what's the best to use and how to apply it. This is old school. I know I won't get the screen to perform like it did but I should be able to get it close enough. I can see where the color, reflectivity, and surface finish can all effect the final result. Another possibility is roof coatings that are advertized to contain aluminum to reflect sunlight.

donaldk · Joined: 17 Jun 2008 Posts: 308

betel · Posted: Tue Dec 07, 2010 1:12 pm Post subject:

"As for the screen, I won't chastise you for putting tape on it."

I figure this screen is probably close to 10 years old and is being affected by its age. Likely the screen had de-laminated at that location and the tape help speed up the process. The adhesive strength of the blue tape is not that great. I had placed 5 pieces of tape on the screen and the center is the only place the surface lifted. Before I refinish it, I will remove any more loose surface material.

I had some "Bumper Chrome" colored enamel in my shop and painted a piece of paper to compare. The color and reflectivity looked very close to my eye. However, under video projection, that area was noticeably darker. I may try to find something similar to the rustrustler with the high aluminum content. I don't think there is any point in painting it with the available white coatings such as Gooscreen. If I thought the Gooscreen Ultra Silver 3D would give the best results, I'd buy it.

CIR Engineering · Posted: Wed Dec 08, 2010 12:22 pm Post subject:

betel · Posted: Wed Dec 08, 2010 1:54 pm Post subject:

Thanks for the comments Craig. I'll probably end up buying some of the commercially available high gain screen paints. paintonscreen.com has one rated at +4 for $180/quart. I think it’s outrageously expensive but cheaper in the long run. I could spend that much buying samples to test and still not find something suitable. I already determined silver tinted enamel will not perform properly. I painted a piece of Bakelite with it; even though it looked very close to the same color, it was noticeably darker under use. A clear topcoat caused bad hot spotting. Just for curiosity, I’m going to try some of the Rust Rustler. It actually contains a significant amount of aluminum and is only $10/quart. The manufacture claims about 8 layers of aluminum floats to the top during curing. Definitely not something you would want on a flat screen. I find it hard to believe Vutec made a screen that is so easily damaged, where a method to repair a surface defect was not developed. They probably did but it may be lost knowledge since it’s been so long since they made them. If you accidently bump it with something, you have a permanent divot. These screens cost close to $2k and apparently considered disposable.

My original goal was to get a screen with more gain and even though it is doubtful I’ll be able to achieve the screen’s original gain performance, I will be able to meet my goal. Who knows, maybe I’ll get improve image quality by sacrificing some of the gain.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

If there is still a little aluminum layer left, then you might try an opaque spray like that stuff people spray on their windows.

betel · Posted: Thu Dec 09, 2010 9:14 pm Post subject:

Took a sample of the screen surface material to our analysis lab at work. The material is almost pure aluminum. There were trace amounts of Si(4.7%) & Mo(0.4%).

Tom.W · Joined: 09 Mar 2006 Posts: 6635

You could try airbrushing some of this just to the damaged area and see if its a close enough match.

http://1stplacehobbies.com/cgi-bin/p_704-1424_n.asp

betel · Posted: Fri Dec 10, 2010 1:14 am Post subject:

After I determined the surface was simply aluminum, I took a piece of aluminum foil and coating the bright side with elmers washable school glue in a stick. Applied the piece to the bad spot, flattening it out with a wallpaper seam sealer and the spot is all but invisible. I really think I could get this very close to oem if I finish the entire screen with an aluminum paint. Paint that actually has aluminum in it. The Rustrustler looks like it has potential but it is oil based. For some reason it seem like a water based aluminum paint would be more suitable.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Maybe I am missing something since it has been a long time since I have seen one, but I believe the screen is supposed to be an opaque layer over aluminized mylar. The theory being that you diffuse a mirror enough that you eventually only get the image back and not the reflection of the tubes. That is why I mentioned something along the lines of a diffuse coating like the stuff they spray on widows.