SquibEvolution
From Simreal
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I had the job of shooting people, cars, and trees, and I had to do it without explosives. So no traditional percussive squibs for me!
I turned, then, to compressed air. Given my background, it was a natural choice.
I was originally planning on make a series of photos for this section, showing all of the very clever designs I came up with, but I haven't done that yet. So you get to suffer along with my verbal descriptions.
Non-squib hits
For shooting cars and trees, I simply shot large gelatine capsules (found in health-food stores everywhere) that had been loaded with dust (graphite was a favorite of mine) out of tubes attached to the pneumatic valves. Like paintball guns, but more complicated and easier to make custom loads for.
Note, however, if you have paintball guns on hand, you can suck the paint out of the ball and replace it with your own fluids.
(NOTE: Not for use against living targets)
Basic Idea
We were shooting living and dead people. When shot, we want the living people to splash blood, and the dead people to "splash" dust.
So I needed a way to hold blood and dust until such time as I blew it up with compressed air.
Simple!
I could take 3/8" pneumatic tube to hold the load, step it down to the 1/4" feeder I use for everything, and seal the big tube in some temporary manner. Apply air, boom! Blood or dust everywhere!
Balloon Squib
I sometimes twist animals out of long skinny balloons (260's in the vernacular), so I have some laying around. Ooh! I can zip-tie the tip of a 260 to the end of the tube. That will seal in the load, and the balloon tip will explode when pressurized. I used a thin layer of vaseline around the tube to help seal it where the zip-tie went.
This works well enough, but the resulting explosive mist is non-directional and not very interesting.
Constrained Balloon
Okay, so let's aim the explosion in one direction. Plugging the end of the tube, I drilled a hole in the side of the tube above the plug. Now I use TWO zip-ties on the balloon end, one above and one below the hole. Fill the tube with a load, pressurize, and the membrane across the hole bursts in a directed mist of blood or dust.
That actually works fairly well.
However, if I try to get the blood load above a fine mist, to get a reasonable spurt, the balloon still stretches too much. All of the blood gets pumped into the stretched latex and, when it bursts, the blood falls to the ground instead of spraying outward.
Replacing the Membrane
So I wanted something that wouldn't stretch like the balloon, but had the other qualities I needed. I settled on plastic wrap, like food-service wrap. A thin film of petroleum jelly above and below the hole, two wraps of a strip of plastic wrap, two zip-ties, and tada!
This directed the explosion nicely, and provided a directed jet of blood or dust. The load was still a bit small, but that could be compensated for by lowering the air pressure (so it didn't vaporize so much) and adding an even fatter load tube upstream from the squib. Or just filling a bunch of the 3/8" tube with the load.
It was, however, a huge pain to make all those little squib tubes, zip tie everything, and so on -- very fiddly.
Quick-Assembly Version
I came up with an easier-to-make version of the above, however. I drilled a larger hole in some 3/8" tubing and cut off a section of tube around the hole. This is split up the back (taking a strip out of the tube), so the cut piece can snap over the squib itself. If I had 1/2" tube, it may have worked even better.
With a snap-on piece and a tube squib, I lubed up the squib, slap an arbitrary piece of plastic wrap over it, snap the faceplate on, and then zip-tie the top and bottom. This is essentially the same as the above version except it was faster and easier to assemble, and it was more likely to leak blood.
Big Squib
None of the above, however, made me happy. There were two problems I had. One was the blood load was not gory enough, and the other was that the powder would compress in the squib and misfire. A lot. This was embarassing. It never did it in the shop, but I had all sorts of problems in the field with it.
So I decided to create a flat-pack squib that did not load the tube, but loaded a packet that was fed by the tube.
If I wanted to dangle the load under the feed tube, I could simply attach it at the end of the tube. If I wanted to feed up from beneath, I could run the tube all the way through the packet so that the load would not be able to flow back down the tube.
I didn't want a bunch of load left in the packet after firing, so the best shape seemed to be a triangle, with the load and the exit window in the bottom tip of the triangle.
An evening spent doing vinyl-glove origami led me to this design.
Start with a simple, cheap vinyl glove. Then fold the fingers up, and then in a diagonal. This makes a nice triangle and leaves the thumb hanging down as a tube insertion point.
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Next, tape the ever loving heck out of the triangle with duct tape. I used black tape, of course. Be SURE to leave a small untaped window on the side opposite the fingers... this is where the glove will burst and spray blood everywhere.
Be sure to fold the wrist hole down once and tape it well -- this is a common point of failure, where the duct tape splits at the wrist.
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Now snip off the thumb, insert a tube until it is near the top of the packet, and zip tie and tape it all together.
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Better Big Squib
Now, as we were experimenting with these (and note, the above packet squibs worked very well), we (my son Nik and myself) noticed that a lot of blood was getting trapped in the fingers and not getting blown out. We hate waste, because any blood being left behind is not getting sprayed on the actors. That will never do!
Nik came up with the simple and yet ingenious idea of NOT folding the fingers over! So I zip-tied the glove shut right where the fingers started diverging (leaving the thumb free). cutting off the fingers, I had a tidy close to the packet at the bottom. Since the wrist was a weak spot, I zip-tied the glove shut there, too! Tada! A somewhat oval pouch with a thumb hanging off.
Tape, tube, and ties later, it's an improved packet. Very nice. More blood, less waste.
But if I filled it too full, the blood would still squeeze up and out of the air tube.
One last refinement, then was needed. Before putting in the air tube, I fed in a length of 1/4" tube that was bent in a semi-circle inside the glove. This acted like a spring, holding the packet open, and as a spacer, forcing the packet to be at least 1/4" thick so it wouldn't squeeze out its blood as easily.
This was the packet we used for most of the later hits.
Brain Squib!
At one point, we need to blow chunky bits of brain out of someone's head. Much of the subtlety of this effect was lost on the film, but we had fun spraying the crew (hiding cowardly behind a sheet of plastic) with blood and brains.
To the above improved squib, I duct-taped about a 1" length of 1" diameter PVC water pipe. This was taped over the window, of course.
I then filled the tube with a mixture of banana and blood. Taking the snipped thumbtip, I lubricated the load pipe and zip-tied the thumb over it.
Now when I pressurized the packet, the window would blow, pressurizing the pipe and thumb, causing that to blow, and blood and banana is sprayed out like a cannon.
Oh yeah.
I may eventually get some pictures in here, including the horrific use of coathangers developed to hold the squib in place on the actor.
