Crack in wall & Black Widow mix advice please

[scw]

I am about to paint a screen on my currently white wall to project my HD65 images but have a problem!

The wall, which is flat and smooth, has a fine horizontal crack in it. This is a bugger because when viewing it at present I can see the line on the projected image.

My question is, if I fill the crack with some fine filler and sand off before painting with BWUK mix, am I likely to still see the crack?

Sadly I suspect that I may and if that is going to be the case then rather than wasting time and paint I wonder whether I should look for an alternative option for the screen?

If I could just go and buy a sheet of hardboard or MDF and fix it to the wall I would, but whilst my screen size is around 96inches wide (2440mm) it is greater than 48 inches (1220) high when watching the full 16-9 format.

One option would be to use an 8x4 sheet centred on the wall and then add a small sliver top and bottom, although whilst this would be fine for films with black borders top and bottom, when I viewed 16:9 stuff I would now have two cracks, albeit uniform and close to the top and bottem edges. Does anyone please have any suggestions to resolve this problem?

Also apologies if I am now going to be covering old ground, but I have read through the relevant threads and would like to clarify the paints I will need to get them ordered ready.

Johnston paint from paint centre tinted to colour code S0907. Presumably it doesn’t matter what make the paint is that they use so long as it is colour S0907? Also do I need Flat matt base, or Vinyl matt? I have also read on another thread some other numbers after this first set, but now can’t find the thread. Are these necessary? How many litres will I need for a couple of coats on a screen 96x54 in size? I guess 1L would be enough?

I understand that I also need 4101 Aluminium base (fine) 120ml, which I can get from SM designs and I should mix 1 part aluminium with 4 parts S0907.

Finally although I have a compressor and spray gun I may buy a HVLP spray system. Would a cheap gun like this Earlex Spray System HV1900 do the job?

Apologies for the long thread but any advise would be appreciated.

[Harpmaker]

I think I would try repairing the crack in the wall first. After such a repair you should prime the wall again anyway and that would be a good way to tell if the crack is still visible. If it is then you can determine if it's best to keep after it until all is well or to go for a new substrate screen.

Since the screen you want is larger than a single sheet of hardboard/MDF you would need to use either a large sheet of plastic laminate or, what has worked well in at least one case here in the States is to build a wooden frame and then staple a sheet of vinyl flooring to it so the underside is facing up, and paint that! If AVForums would allow a link to my "home" forum (that's where the thread is) I would be glad to share this fellows method of using the flooring material. It's one of the easiest ways to make a REALLY big screen other than simply painting a large wall.

Can't help you on the BWUK formula, but I'm sure others will be happy to.

If you spray your screen, I highly recommend using a HVLP gun to do so. Conventional high pressure guns waste too much paint and are a real mess, which I'm sure you are familiar with if you have a high pressure setup. Also, while house paint must be thinned with water (at least in the U.S.) to spray properly though a HVLP gun, I think it would have to be even thinner to spray it with a conventional gun. I think Custy has a gun similar to the one in the link you gave, he might have a few tips for you.

[scw]

Many thanks for your response. I will certainly have a go at repairing the hairline crack, but I have my doubts I will be able to get rid of it for ever…they always seem to show don’t they!

However your idea of vinyl flooring is a good one and has got me thinking. A piece 96x54 inches is really only and off cut and if it’s thick enough I guess it would be possible to just hang, or stick, on the wall without any framework.

As I recall though doesn’t vinyl flooring have a textured back to it? Surely this would show on the projected image?

[custard10]

scw - the earlex you refer to was used by someone previously to paint BWUK and i think it turned out just fine.
i am using a similar tool - Silverline 633844 600 Watt HVLP Spray Gun: Amazon.co.uk: DIY & Tools

you may have seen a mention of a crown paint mix that i had tested. we are not using that anymore so disregard that info.

so you need:
1) s0907 y70r in vinyl matt(or acrylic matt) 4 parts
2) Autoair aluminium fine 1 part

id like to help you on the amounts needed but i am strugggling to recall how much people used. i'll need to revisit the BWUK thread.

[scw]

Originally Posted by custard10

scw - the earlex you refer to was used by someone previously to paint BWUK and i think it turned out just fine.
i am using a similar tool - Silverline 633844 600 Watt HVLP Spray Gun: Amazon.co.uk: DIY & Tools

you may have seen a mention of a crown paint mix that i had tested. we are not using that anymore so disregard that info.

so you need:
1) s0907 y70r in vinyl matt(or acrylic matt) 4 parts
2) Autoair aluminium fine 1 part

id like to help you on the amounts needed but i am strugggling to recall how much people used. i'll need to revisit the BWUK thread.

Thanks custard

[Harpmaker]

Originally Posted by scw

Many thanks for your response. I will certainly have a go at repairing the hairline crack, but I have my doubts I will be able to get rid of it for ever…they always seem to show don’t they!

Cracks can be a problem if the reason the crack formed in the first place isn't corrected - and that can be a problem.

However your idea of vinyl flooring is a good one and has got me thinking. A piece 96x54 inches is really only and off cut and if it’s thick enough I guess it would be possible to just hang, or stick, on the wall without any framework.

As I recall though doesn’t vinyl flooring have a textured back to it? Surely this would show on the projected image?

Over here in the States some flooring has a texture on the back, but most of the cheap stuff we would use as a screen substrate doesn't, it just looks and feels like heavy paper.

The vinyl flooring we have here NEEDS a supporting frame since it wants to curl badly if not supported (or glued down on the floor as it was designed to be).

I've been looking for a material I could simply paint and hang and not have it curl, warp or sag when not in a frame - I'm still looking.

I hope I don't get in trouble for this, but here is the flooring thread I was referring to (I put it at the end of this post so it will be easy for a mod to delete if necessary ): Mega Screen™ - Black Widow Flavor - Home Theater Systems - Electronics and Forum - HomeTheaterShack