Helium filled bubbles

[Stagebob]

Anyone have experience in using helium to produce bubbles front of stage to use in underwater scene? I guess we can just pump helium through detergent solution, but not sure of best way to control size of bubbles. Just trying to look at feasibilty of producing a rising "curtain" of bubbles.

[Ynot]

Not quite sure why you'd want to use helium, tbh...

Standard bubble machines produce bubbles that are pretty light anyway, and whatever you use isn't likely going to make the bubbles any more controllable so they're going to go pretty much wherever they want once they're created.

In theory, I guess, helium variety may tend more towards going up and not down at all (which of course regular ones will do) but how you'd use helium (on, I presume, any kind of low budget) isn't something I guess that would be easy...

[ImagineerTom]

Helium is lethal by displacement - it doesn’t kill you but it stops you inhaling enough oxygen so you have zero chance of writing a risk assessment to show that pumping helium into the auditorium can be done safely….

I would also have to do the maths but my instinct is that the volume of helium relative to the weight of the bubble would produce negligible “lift”

You can make bubble go up by blowing them with a fan but pretty quickly the come down again ruining the effect you are trying to achieve. I’m not sure what you describe is possible at all to be honest. 

[wellthatsbroken]

Displacement is not really an issue.  Even from the gigantic 300bar cylinders you get from BOC now, you only get ~12m^3 of gas.  In a theatre that’s virtually nothing.  Helium always rises, even at cryogenic temperatures (4K), so unless you have someone with their head placed against the ceiling, asphyxiation is not an issue.  At the flow rates you are probably going to be looking at it’ll be the same as welding argon.

The problem that might set you back is the sheer cost of helium at the moment.  There is currently a shortage, and BOC is rationing bottles of pure helium to uses with a good use case and based on previous order volumes.  You’ll probably be able to find balloon gas, that’s a diluted He mixture with oxygen and CO2, and that’s what you’ll have probably have seen in most shops.  A large cylinder, standard cylinder size would be £384.29 from BOC, plus the delivery and cylinder rental and ~£250 for a regulator.

 

 

At these sorts of prices, it would be worth doing a test by getting a balloon from a shop and making some bubbles first to see if the effect works.

Edited February 10, 2022 by wellthatsbroken
typos

[ImagineerTom]

[quote]Displacement is not really an issue.  Even from the gigantic 300bar cylinders you get from BOC now, you only get ~12m^3 of gas.  In a theatre that’s virtually nothing.  Helium always rises, even at cryogenic temperatures (4K), so unless you have someone with their head placed against the ceiling, asphyxiation is not an issue.  At the flow rates you are probably going to be looking at it’ll be the same as welding argon.[/quote]

I've got to push back here as you're making all sorts of assumptions about what the venue is. 12m3 in Theatre Royal Drury lane (with its new super fancy ventilation system) isn't really a risk, but 12m3 in a small theatre with Scaff grid or bars mounted directly to the ceiling and poor ventilation; suddenly someone climbing a ladder to refocus a light is sticking their head right into the helium zone. Same problem if its an older house with a flytower and grid with no specific ventilation at grid level - half a dozen performances and you could very create an effectively oxygen-free grid. Some theatres have a ventilation system that constantly changes the air in the auditorium, others recycles a certain amount of the air so the helium could end up being recycled into the auditorium and again pooling in an area with poor ventilation and causing an issue. Since there have been HSE prosecutions / fines for shows pumping oxygen displacing gas into an auditorium causing injuries you've got quite a high standard to meet to justify the claim that you can do it safely and have all the appropriate procedures and hardware in place.

[mikienorth]

Does work, can be done, not easy, people I work alongside developed machines specifically to do this at an arena scale, along with filling them with smoke before comemercially available large scale machines came on the market.  

Another option used to give the idea of 'underwater' is mounting the bubble machines high and letting them just do their thing in the room.  The idea of bubbles in the water is possibly more important than the direction they travel to sell the design?

[Ynot]

Considering that the OP is in am-dram I'm going to conclude that, to be fair, this is likely going to be a director's 'vision' versus what is practicable and affordable for that stage. 

[Dave m]

Would a heat source in the area of a standard bubble machine provide enough lift?

it could be combined with projection

[the kid]

Bubbles will bubble. Just let them do their thing, assuming its nothing special (bubbles falling out of a chest would be hilarious imho) 

BUT ignoring all the gas issue, its gonna be wet and slippy and hell. 

[ANDYLASER]

On 2/12/2022 at 2:50 PM, Dave m said:

Would a heat source in the area of a standard bubble machine provide enough lift?

A slow speed fan might be more successful.

[kitlane]

Once you get a decent amount of bubbles on stage the audience will 'ooh' and 'aah', and frankly they won't give a monkey's about what direction they are moving. I'm assuming that there will also be actors and/or dancers on stage at the same time, and their movements will inevitably push the bubbles around and pop them quickly.