Cgiii

[benven]

Note, this is a spray only application. Also, a white primer base, instead of just spraying on the foamboard will help bump up performance.

If there are any questions, please let me know.

benven 06-27-06 07:34 PM

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New CGIII Mix

Latest on my screen. Just repainted before the World Cup and boy does it look nice.

Substrate is white foamboard. I have been unable to replicate this mix on anything but foamboard. I have not tried Sintra, Durotherm or Parkland. I do know that painting a piece of MDF with any sort of white paint does not work.

Caution. Foamboard will twist and warp when dry. I had mine in a wood frame and had to add velcro strips in the corners to make the screen sit flat against the wall when I mounted it.

Unfortunately, the mix must be sprayed. Rolling yields disco ball effects ie lotsa sparklies. Spraying virtually eliminates that sparklie effect.

Mix is as follows:

24 parts of water (I used just tap water)
24 parts Clear Matte Polyurethane
24 parts Daniel Smith Interference Silver
1 part Pearl Ex Silver Powder

2 coats only. Each coat should be wet, no dusting here. I did add an accerlant to help it dry between coats. If you are not good with a spray gun, yo may need more than 2 coats in which case the screen's performance does diminish. You should end up with a matte, light silver coloured surfacw when done.

I figured out, after I painted my full screen , that a primer or UPW coating on the foamboard helps even further. Rolling that is fine even if you do not sand it. Obviously sanding the primer coat will help.

Thanks to a very generous and patient forum member, the measured gain is 1.8 with a half gain of 30 degrees. RGB measures out at 224/214/217. Not too shabby. No primer coat on the tested sample. Just 2 coats of the mix on white foamboard.

Is this a light buster? Not really. But let me just say that it is much more viewable than anything I had up on my wall. The World Cup games are incredible during mid afternoon.

No comparison screen shots since I don't want to put any dings or scratches on this baby. Let me just say that this mix has really put a big smile on my face. Like this and this And has my guests, who have been coming over regularly to catch the WC games, doing this

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Foamboard is as the name implies a layer fo foam sandwiched between a layer of paper. I don't know why it works better than painted MDF, but it really does look much better. The difference is in the gain, higher on foamboard, sparklies, much, much lower on foamboard and texture, much less on foamboard. You can buy small pieces and do a test. A 4' x 8' piece only cost me $20 Cdn, taxes in. And it was the perfect height for my set up.

I was even thinking some heavy photo backdrop paper may work. But I haven't tried it yet and I am all out of the silver interference paint. Besides, it's summer and I am taking a break from all of this stuff and enjoying the 8 weeks of good weather we get here.

This is where I bought the foamboard:

http://www.currys.com/artistsmateri...tID=766&catID=4

This is where I bought my Pearl-Ex Silver powder:

http://www.shadesofclay.com/Article...ts/Powders.html

The above are Canadian sites. I'm sure there are plenty of sites you can get these materials from. But it will get you started.

This is where I purchased the silver interference paint from:

http://www.danielsmith.com/cgi-bin/...006062814533020

The clear matte poly I used is from Home Depot. Behr product.

[wbassett]

Great addition and we promise it won't get burried or lost!

[benven]

Now for something I haven't stated in public... I believe (actually tested and know) that the Behr Matte Poly yellows over time. I have noticed it in this screen over time. I have done some other side by side tests with other satin poly only mixes and then a Behr matte poly mix with the other ingredients being the same. It takes a while to really get yellow and your eyes adjust. I just made the discovery when I started monkeying around again with paint brews at the beginning of this year. I put up a matte white panel and boy it is yellow.

What I do know is that I am not happy with the performance of CGIII anymore because of this yellowing. Initially, the screen had great whites for this shade of gray and gain. I have been playing with pearl topcoats, matte varnishes, matting mediums (or is that media?) and the Behr product. Thus far, nothing I have come up with is good enough, IMO, to replace the CGIII.

Please don't take this the wrong way..the Behr product is a great product. It levels out nicely, rolls on well and really helps deepen colours. However, it does yellow over time, ever so slightly. You won't notice unless/until you put up a reference white panel.

[mechman]

You're just the bearer of good news aren't you... :raped:

I'll keep an eye on my FG and no dance banana for you!

mech

[Tiddler]

I have wondered about the possibility of the Behr Matte Poly Yellowing in time. We could compensate for it with a slightly more blue base coat. I know benven has a preference for white screens with pearl top coats but for those who like a gray screen we could use a 3:1 ratio of LB:YO. It will be a bit cool at first but as the poly yellows it will become more neutral.

Benven, have you tried the Pratt & Lambert dull finish polyurethane?

Lowes also sells the American Traditions clear matte protector. I think Lowes is building stores here in Canada now, so we may be able to try it.

[mechman]

From what I understand the yellowing occurs as a result of exposure to UV light. In my basement setting I'm thinking that's at a minimum. <fingers crossed>

Todd, That's an acrylic isn't it? From what I gather from woodworking magazines, acrylics do not yellow. We'll have to redo some stickies.

mech

[wbassett]

benven wrote:

Now for something I haven't stated in public... I believe (actually tested and know) that the Behr Matte Poly yellows over time.

That's the problem with most poly's, they do tend to yellow over long periods of time. I know of some people that have played with floor coatings and resins as the optical coating. This is one area that is finally getting some attention and I think that is a very positive thing since it is universal to just about any screen method.

[benven]

I haven't tried the Pratt and Lambert polyurethane. I have also not tried any floor coatings. A Lowes is opening up soon in Hamilton. That's where I technically live. So, as soon as it opens I'll go out and get the American Traditions product. I have tried the Liquitex Matte Varnish product. Another excellent product, but it does entrain alot of air and create bubbles when rolled. With careful rolling you can mitigate the bubble formation. I know this product does not yellow over time. Also, the Varathane polys do not yellow over time. Problem is, even satin is too glossy to be used by itself and needs to be deglossed a bit. Yes, I have tried mixing the Liquitex product with the satin polys and it works. But again, bubbles. I'll keep on experimenting and let you guys know what other observations I make.

[Tiddler]

From the Behr website page on the Matte Polyurethane:

BehrPaints.com wrote:

This ultra hard finish is ideal for use over interior painted, faux-finished, crackled and textured surfaces. It will enhance the look of the finish and protect it from moisture and wear. It dries to a durable, non-yellowing, clear, long-lasting matte finish.

It does specifically say for over interior paints so maybe there are no UV additives in it. If there is a lot of sunshine hitting Benven's screen that may be why it yellowed.

[benven]

There is sunshine hitting my screen. Not alot. I try and keep the shades pulled down during the day. But there is still a bit of light entering the room but not directly at the screen.