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Damonk
05-20-2009, 05:18 PM
Help! I need some ideas about how to make a spacesuit vent gas!

In my script, a hole in the leg of the astronaut's suit vents a stream of gas after an accident on Mars.

My initial plan was to feed a tube under the suit, leading to the hole and attach the other end of the tube to a powder-based fire extinguisher. HOWEVER, this idea hasn't worked out. The tube gets blocked really quickly and the extinguisher pumps out way too much powder - which additionally is really messy!

What I need it a nice continuous stream of pressurized gas blasting out of the suit - dry ice would be ideal but I've no idea how to make this work. I'm also concerned that there might be safety issues with a tube of dry ice running past the actor's thigh.

I intend to supplement the effect with a particle emitter in post, such as can be found in Motion for example, but I'd prefer to have a real stream of gas coming out of the suit if possible.

If anyone has any bright ideas about how to make this work - on a budget! - please let me know!

mdslammer
05-21-2009, 04:19 PM
One alternative would be to use After Effects. This can be done in post. If you don't work with the program, then check around and find someone who does.

There are several forums and user groups. We have one here as well.

Good luck.

pixelated
05-23-2009, 03:07 PM
Having fired your dry chemical fire extinguisher, you're now aware what a mess they make.

I think you're on the right track with the tube up the leg, although dry ice is asking for frostbite. CO2 is also actually a colorless gas, the white fog is actually frost and frozen co2 particles

One suggestion would be one of those pump up style tank garden sprayers. Make sure it's totally dry and try some baby powder in the tank, maybe a little glitter in the tube, experimenting's half the fun. Pump up, Shake well and squirt. These also work for powering blood squibs, pipe leaks, etc. Very handy and cheap. Don't have the pick up tube in the powder or you'll have another mess . . .

Good luck and must post clips.

ChipG
05-23-2009, 03:58 PM
Hmm,

Maybe a can a freon from the autoparts store and a longer hose? It does come out as a white vapor gas, I think you can buy a valve for the can for $10 that adjust pressure, turns it off and on. I know when you turn the can upside down you get more of the white freon vapor and less when it is right side up.

It might work, I'd spend the $20-$30 to aleast try it.

FYI the new freon is enviromentaly friendly.

Damonk
05-24-2009, 05:32 PM
Yeah - we're going to use something similar in Motion - but I want it in combination with something real.

Damonk
05-24-2009, 05:34 PM
Tried the baby powder out in a garden pump today - but without success! It was just to faint - not enough of it was coming down the tube. I'll go and track down some Freon now and give that a go too!

troopercooper
06-02-2009, 03:52 PM
Considered a quick burst of something while overcranking the camera?

Gary Sconce
06-25-2009, 07:58 PM
Run a tube from the nose of a fog machine and press the button emitting fog from the tube. Film the emission. If you want a smaller amount, as the fog machine ends its blast, film the residual gases emitting from the tube.

A CO2 fire extinguisher connected to the tube will work also.

Don't allow the fog to burn your actor as it comes out hot, and the CO2 comes out freezing temp.

Gary

CharlieG
06-25-2009, 08:39 PM
I think space suit air is actually unseen but the tear and movement from the material is noticeable ... I used to work for NASA TV

Damonk
07-17-2009, 06:39 PM
The fog machine is a good idea. I've tried the C02 extinguisher, but it blocked up. Meanwhile, I think the air would be invisible, as you say, CharlieG - but I suspect on Mars it would freeze as it emerged from the suit, creating a blast of ice crystals - which would be briefly visible... But I could be wrong!

KKeller
07-18-2009, 02:48 PM
A can of compressed air comes out white when shaken or turned upside-down. How tight is the shot going to be?