Concert "smoke." What exactly IS it?

Factual Questions
1

The wife and I were at a show in Vegas Monday night. As the group (Human Nature - strongly recommended!) launched into “Baby, I Need You Lovin’”, my eyes started to tear up. "Hmmmmm, thought I. “The Four Tops don’t usually make me react like that.” Then I noticed that there was a lot of generated smoke from under the stage. This smoke issued at several other points in the show. Each time my eyes went teary and my throat started to ache.

Cigarette/cigar smoke doesn’t do this to me, and nobody else in the audience seemed to be weepy either. So what the hell is in that stuff that I’m obviously sensitive to? Doper staging people?

2

In the old days, “smoke” was usually generated by dropping blocks of dry ice into tubs of water- but there may be better ways to generate such smoke now.

3

Most likely propylene glycol vapor - the same thing produced by ecigarettes.

4

Theatrical smoke comes from smoke machines. Smoke machines drink fog juice. The juice usually contains some kind of glycol.

5

Yep guys glycol and water,

There are actually two types of concert “smoke” fog and haze. Fog is the cloud you see coming from one or more points on stage, the glycol mixture is heated and forced thruogh a nozzle to make it spray, almost exactly like the bug foggers you can buy a Home Depot. Haze is the same stuff with more water and a more open nozzle, it lingers like cigarette smoke. Both are supposed to be non irritating and harmless, which brings me to…

Used to be fog juice was nasty oily stuff. It would leave a residue all over the place and IIRC mildly toxic. I have not seen the stuff in 8 or more years. It does OTOH make a better longer lasting fog. Old style fog can do exactly what you described happening to you, so much so that one singer I used to work with had me unplug all fog and haze devices and have me tell the lighting tech not to use it.

I WAG that they were using the old style juice. I don’t know of anywhere to buy it still but it could still be around.

Capt

Pro sound tech since 96’

6

Thank you. I knew somebody here would know. It didn’t interfere with my enjoyment of the show. It just made me feel strange that I was crying to The Four Tops. :smiley:

7

Actually there is a third smoke effect, the kind that lies on the floor, this is made with CO2 snow and water.

8

The smoke that stays low is from dry ice, the smoke that rises is from smoke generators. both are used

9

And an entirely different kind of smoke effect that occurs during String Cheese Incident, and similar, concerts.

10

The old style stuff you’re describing sounds like it could be made from glycerin (instead of a glycol), which can produce acrolein at higher temps.

But if you’re talking really old-style, it could be one of the other, much less “OSHA-kosher” methods discussed in this paper.

11

I was gonna say, one way to determine what concert “smoke” is is how it smells…

12

I think the band Great White used a different method. Too soon?

13

Quite correct, I forgot all about that. Rarely used in my world but often in the Theater.

Thanks

Capt

14

Egad, don’t want to know how much of that I have inhaled over the years. Thanks for the links

Capt

15

I knew it! Those sparking consoles and smoke are all for show, aren’t they, Captain?