# creating a screen of fog



## innovation88 (Jan 26, 2010)

Has anyone successfully created a screen of fog that can be projected on (with a video projector) from behind? I know that you can buy the FogScreen; however, it costs thousands. I need to create a fog screen for hundreds. 

Any suggestion is welcome. 

Thank you!


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## Viirus (Jan 26, 2010)

If you´re doing indoors in a space where you can shut off the aircondition/ventilation, you can try this: Use CO smoke and lead it into a pipe with holes drilled in a row on the underside. The pipe can´t be too long, ours was about 2m. The size of the holes you have try out. If you can use a compressor to press the smoke into the pipe the holes can be smaller, creating a thinner wall of fog. We didn´t use a compressor and the size of the holes was about 10mm in diameter. The distance between the holes were about 5cm. We didn´t use this with a back projection, but it worked fine with frontprojection.


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## SHARYNF (Jan 26, 2010)

how long were you able to maintain the screen effect? what smoke generator were you using? it just kept falling and then dissipated so there was no build up? have you tried this using the typical water based fog juice?

Sounds interesting

Sharyn


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## innovation88 (Jan 26, 2010)

Not to sound unknowledgeable, but what is CO smoke?

We are doing this indoors; so, yes, we will have extensive control of the facility.


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## jcfalc01 (Jan 26, 2010)

My guess is that the "CO" smoke is really "CO2" (or dry ice fog). It can be used with a chemical fog generator or with heated water; a blower motor makes both work much better.

Of course, I'm thinking that you want this to be a fairly large veil to project onto. Might I suggest the use of a scrim with piped dry ice fog from above to give the illusion of a veil of fog? That would give a more consistent layer that would look "phantom" like.

Again, use of one of these Home Depot blower motors that are typically sold as floor fan units (our custodians use them to dry wet or waxed floors) really adds in allowing the fog to be forced out of the pipe. I would recommend at least a 3 in pvc pipe with holes drilled in it (probably 5/8 or 3/4 " holes). Use flexible plastic dryer vent pipe duct taped to the blower motor fan to transmit the pressure.

Hope this helps.


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## zuixro (Jan 26, 2010)

jcfalc01 said:


> My guess is that the "CO" smoke is really "CO2" (or dry ice fog). It can be used with a chemical fog generator or with heated water; a blower motor makes both work much better.



I hope Viirus meant CO2 smoke. CO (Carbon Monoxide) smoke would be really bad...


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## Morpheus (Jan 27, 2010)

innovation88 said:


> Not to sound unknowledgeable, but what is CO smoke?
> 
> We are doing this indoors; so, yes, we will have extensive control of the facility.



I would double check you level of control - often times now the air handlers are automatically controlled, and it's a ***** to turn them off (other than cutting power, which has issues as well)


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## Dalamar (Jan 27, 2010)

Needing a blower, fan or forcing air into a conduit of any kind is a general misconception for creating fog walls with Low-Lying Fog. 

a) Forced gas (air, CO2, N2..) into a conduit increases pressure. That’s a given. Increasing pressure augments temperature… on cold fog. That defeats the purpose.
b) Forced gas into a conduit creates turbulence. Turbulence breaks down the fog, reduces its density and, ultimately, becomes too thin to reflect sufficient light. Defeats the purpose, too. 

What you need to do is use an ICE FOG Q, split conduits to each end of an isolated recipient, as long as required (no more than ~20’), let it fill with fog (which will settle and densify) and let the overflow fall off. The sheer pressure form the liquid refrigerated CO2 will be ample push for your purpose. Even then, the fog falling off will tend to expand as it warms up, so the lower wall will not be as straight as the top. 

Also, front projection will give you higher image intelligibility than rear, which will create a “ghost-like” result. 

For further help/ tips, contact me at the office.


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## SHARYNF (Jan 27, 2010)

my understanding is that fogscreen uses an ultrasonic water based system, not unlike in concept the units that are sold for misting plants

Ultrasonic Water Fogger-The Mist Maker

Obviously the fogscreen uses a setup where there is more control, but it is actually just plain water

Sharyn


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