Pneumatic Squib For On-Actor Film Blood Effects

Step 4 Using the Effect

Use of the Effect:

1. Fill the effect tube and cover the output hole with the smallest possible piece of low-tack masking tape.
2. Tape the effect under the actor's clothing in the appropriate orientation. If the tube must be oriented with the output hole higher than the quick-exhaust, I recommend pushing a plug of banana down the hose before filling it with stage-blood.
3. Dress the actor in the outer costume and pass the control module down the actor's sleeve to their hand.
4. Make a very small cut in the costume over the output hole of the effect. The smaller the hole, the more blood will stay on the actor's clothes. The larger the hole, the more blood will spray away from the actor.
5. Flip the switch towards the control line fitting and connect your air supply to the air inlet. Pressurise to between 60 and 100 PSI. (use a pump with a gauge, or a compressor with a regulator)
6. Disconnect your air supply and film the scene - the check valve will keep the squib pressurised.
7. When the actor is ready, he can flip the switch and the effect will trigger.

Comments

[Sruggiero86]

So I made this following all of the directions and the chamber wont fill up...could my mini exhaust vale be faulty....it feels like only 2 psi comes out

[Crosius]

Hmm. Do me a favour and unscrew the mini exhaust valve from the pressure chamber. Attach your pump and see if air flows easily out of the mini exhaust valve when you pump. Without the tank attached, there should be no obstacle to air flowing out of the exhaust valve and you should feel a good air flow. Let me know what happens.

[Sruggiero86]

I think it's me... I guess 100psi feels like a lot less pressure then I though...are there bigger volume chambers that will hold a greater psi for a more powerful effect, or could i use a thinner tube to fill with the stage blood?

[Crosius]

Have you tried using the squib with the effect tube full of water? 2 cubic inches of 100psi air doesn't feel like much, but if it has something to push against it has plenty of energy. If you've found that your squib "squirts" for too long, you may just need to enlarge the hole in the effect tube. If you do decide you want more energy available to the effect, all the parts from Clippard are rated to work up to 250psi (max), so you can try pumping your squib up to 150psi. I wouldn't recommend going any higher than that, as it's a good idea to leave a safety margin for temperature changes and the 1/16 hosing sometimes has flaws that cause it to burst at higher pressures. In my testing, I found that too much pressure tended to make the stage blood turn into a fine mist that didn't show up on film very well, so you'll have to experiment. There are larger volume chambers. Clippard makes them in 2.0, 2.4, 3.6 and 4.0 cubic inches. That would give you more air volume (and allow you to use more stage blood) at the cost of increased bulk to conceal under the actor's costume.