[ohcello]

I asked this of MM in my own thread, but figured I'd float it to the group. I've seen mention of Behr SS plus poly mixes, but also read about some who do a poly 'topcoat'.


Is one better than the other or is it still being debated a bit? I just screwed up a coat of SS plus poly (way too much poly by mistake), so I see streaks of SS ...maybe they'll be gone when it's fully dry, but I doubt it..... so I plan on lightly sanding down this latest 'mistake coat' and applying one coat of SS and then one final coat of either 3:1 SS + poly OR one poly topcoat....


thoughts?


Also, when mixing I have been using Poly satin.... but if I do a topcoat, should I do poly matte?


Thanks all!

 

[pb_maxxx]

there really is no debate here.


the consensus is that if you are looking to remove a hotspot such as that which can occur on a wilson art fashion grey then a topcoat is warranted. however, even those who are done so have reported a dulling/blurring (less sharp) of an image due to the topcoat.


otherwise, mix polyacrylic in with the mix.


the culprit of doing a topcoat is this...

the flattening agents in the minwax polyacrylic satin or behr faux glaze matte dull/blurr the projected image as it passes through to the SS basecoat. the image is further degraded as the refracted light comes off the basecoat and refracts back through the topcoat to the viewer.

 

[ohcello]



Quote:
Originally Posted by pb_maxxx /forum/post/18233767


there really is no debate here.


the consensus is that if you are looking to remove a hotspot such as that which can occur on a wilson art fashion grey then a topcoat is warranted. however, even those who are done so have reported a dulling/blurring (less sharp) of an image due to the topcoat.


otherwise, mix polyacrylic in with the mix.


the culprit of doing a topcoat is this...

the flattening agents in the minwax polyacrylic satin or behr faux glaze matte dull/blurr the projected image as it passes through to the SS basecoat. the image is further degraded as the refracted light comes off the basecoat and refracts back through the topcoat to the viewer.

Great information, thanks so much!


OK, so I'l lightly sand, then one coat of SS, then one final coat of SS/poly mix 3:1 and that should do it for my wall for now! (until I get a big piece of Sintra or something like that and spray it with Silver Fire =)=)

 

[bud16415]

Addition of poly to flat paint increases the paints ability for Specular reflection by a varied degree based on the concentration of poly to paint. Thus giving the DIY screen builder the ability to experiment and find a level of specular reflection appropriate for their screen size, projector, room environment and seating position. An added bonus is it allows the paint to level better and once dried resist dirt etc.


The poly combines with the paint and causes some other light changing properties as PB described above. Anytime you thin paint with poly you decrease the ratio of pigments to filler in the paint, the filler being the clear poly. Thus light has to pass thru some amount of clear poly before striking pigment that will return it and then back thru the poly again. So there will be changes. There will also be reflection directly off the poly rich surface, just like looking at a pond and seeing reflection of the sky and trees on the other side. This could be part of the ambient rejecting properties poly provides and also the ability it has for causing hot spots if the concentration is too high.


I personally think it's very hard to decide on the amount of poly required by someone else given all there particular factors. That leaves experimentation as the best system to use. I advocated finding the right gray level first and then work on deciding if poly and some limited amount of specular reflection helped beyond that with picture quality.


I suggested a base coat, top coat method more to save on poly than any other reason. I painted my screen with four coats the first two were flat paint only. That allowed me viewing time on a full screen while comparing large samples with the blended top coats.


Below are two photos taken of the very same gray paint in the 4 sections of the test screen with different levels of poly, one of them pure poly of the lowest luster I could find. One photo is with room lights and the other with cam flash. The results in the two photos are very telling of what the poly does.

 

[ohcello]



Quote:
Originally Posted by bud16415 /forum/post/18234162


Addition of poly to flat paint increases the paints ability for Specular reflection by a varied degree based on the concentration of poly to paint. Thus giving the DIY screen builder the ability to experiment and find a level of specular reflection appropriate for their screen size, projector, room environment and seating position. An added bonus is it allows the paint to level better and once dried resist dirt etc.


The poly combines with the paint and causes some other light changing properties as PB described above. Anytime you thin paint with poly you decrease the ratio of pigments to filler in the paint, the filler being the clear poly. Thus light has to pass thru some amount of clear poly before striking pigment that will return it and then back thru the poly again. So there will be changes. There will also be reflection directly off the poly rich surface, just like looking at a pond and seeing reflection of the sky and trees on the other side. This could be part of the ambient rejecting properties poly provides and also the ability it has for causing hot spots if the concentration is too high.


I personally think it's very hard to decide on the amount of poly required by someone else given all there particular factors. That leaves experimentation as the best system to use. I advocated finding the right gray level first and then work on deciding if poly and some limited amount of specular reflection helped beyond that with picture quality.


I suggested a base coat, top coat method more to save on poly than any other reason. I painted my screen with four coats the first two were flat paint only. That allowed me viewing time on a full screen while comparing large samples with the blended top coats.


Below are two photos taken of the very same gray paint in the 4 sections of the test screen with different levels of poly, one of them pure poly of the lowest luster I could find. One photo is with room lights and the other with cam flash. The results in the two photos are very telling of what the poly does.

interesting.... one issue I have however is I have to hurry up and finished painting my wall very soon as my entire basement is out of commission and reaks of poly..... I cannot experiment too much longer.... so I have to try and put something on there that will most likely work well enough and then only if I *must* change it will I do so...



Of course, down the line, if I ever get a PVC board or something else I can experiment all I want with metallic mixes, etc.....in the garage before final install...

 

[ohcello]

So I think I'm finished painting my perhaps-temporary screen/wall...


It has primers, basecoats and Behr SS plus Poly (satin) as the final coat...3:1 ratio...


My question is this: What sheen should it appear to have to the eye? It really looks quite flat to me despite the 25% poly in the mix.... is this normal? Perhaps there is a touch more sheen than flat, but it does not appear to be much.


Just curious as I don't think I want to change anything until I get my projector later in the week to really test it.


Thanks.

 

[bud16415]



Quote:
Originally Posted by ohcello /forum/post/18240463


So I think I'm finished painting my perhaps-temporary screen/wall...


It has primers, basecoats and Behr SS plus Poly (satin) as the final coat...3:1 ratio...


My question is this: What sheen should it appear to have to the eye? It really looks quite flat to me despite the 25% poly in the mix.... is this normal? Perhaps there is a touch more sheen than flat, but it does not appear to be much.


Just curious as I don't think I want to change anything until I get my projector later in the week to really test it.


Thanks.

Mine is a 50/50 mix and looks like this.

 

[ohcello]



Quote:
Originally Posted by bud16415 /forum/post/18242216


Mine is a 50/50 mix and looks like this.

wow thanks... ok so that looks to not have much sheen (to the eye anyway).... so I'm probably ok.


Wow 50/50 mix.... how did you do that without having the paint and poly 'break up' on you? I attempted to do very close to a 50/50 mix and the paint and poly seems to break up on me no matter how much I stirred/mixed it, etc.

 

[bud16415]

I have never seen the separation you mentioned. The water based poly and the water based paint I used seemed completely compatible.


When I first thought to try this quite a few years ago I had concerns if there would be any adverse interactions in doing this and I started a thread asking if anyone had any input and PB posted that he had been doing this and indeed it added some good PQ enhancements. He had then taken it beyond poly by adding other things. But you are the first I have heard of that had separation issues.

 

[ohcello]



Quote:
Originally Posted by bud16415 /forum/post/18247274


I have never seen the separation you mentioned. The water based poly and the water based paint I used seemed completely compatible.


When I first thought to try this quite a few years ago I had concerns if there would be any adverse interactions in doing this and I started a thread asking if anyone had any input and PB posted that he had been doing this and indeed it added some good PQ enhancements. He had then taken it beyond poly by adding other things. But you are the first I have heard of that had separation issues.

Just realized I think I have the wrong poly!... I posted a question for all to see.... about poly regular vs. polycrylic..... my mistake not checking the can after I asked for polycrylic!!... =(

 

[blastermaster]

I'm about to do the same thing with my home theater screen. I have put down two coats of Kilz2 primer (can still see a few lines where I didn't get as much coverage with my sprayer as others but is it necessary to make it totally uniform since it's just the primer?) and have bought CIL Snow Field Matte finish with polycrylic. My CS plus gun seems to be good with 20% water dilution for regular paint (even higher with that sticky Kilz2), but does the polycrylic dilute the paint and, if so, how much water do you use if I'm using say a 3:1 ratio? I think I'm going to lay down some regular paint coats first, then use the paint/poly mix. I'll post a link to pics once I get them up. Thanks for the help.

 

[blastermaster]

Well, I'm loving this Wagner gun. I painted my ceiling tiles a nice dark grey (which look waaay darker once they're on the ceiling) to get a feel for using the gun. I fixed some issues with my drywall before painting (that BW stuff has a way of uncovering all manner of drywall sins), then went to town. I did a 20% dilution of paint to water and did two coats. Then I did 3 parts diluted paint to 1.5 parts polycrylic satin. I did one solid coat and a final duster coat. Results? I'm totally stoked. No more roller marks that plagued my last screen (esp. in sky scenes).


I calibrated my projector to the best of my ability using DVE HD basics.


Here are the shots:

http://s836.photobucket.com/albums/z...t=IMG_1766.jpg

http://s836.photobucket.com/albums/z...t=IMG_1781.jpg

http://s836.photobucket.com/albums/z...t=IMG_1783.jpg


The screen shot of TDK is a bit overexposed on the rooftop (camera) but I really like the fact that due to the lightness of the grey, I get nice brights yet still good black levels.


Honestly, for the money it cost, A Wagner gun is totally the way to go when doing a screen imho. It's become my favourite "toy". Now I just have to find something else to paint...

 

[ohcello]

very nice!....