Pneumatic Squib For On-Actor Film Blood Effects

This Instructable is derived from available Internet resources on fabricating special-effect blood-shooter devices from hand-pumped garden sprayers. It seeks mainly to minaturise the design.

This particular design grew out of a general dissatisfaction with the restrictions the garden-sprayer style of blood-shooter placed on the staging and choreography of blood effect shots.

The goal was to create a device that could replace the garden-sprayer design in all situations, and add flexibility in staging effect shots.

Step 1 Building the Control Hose

The Control Hose carries air between the hand-held remote section of the device and the effect section of the device. It is the simplest element to construct, so we'll build it first.

The control line consists of only two unique components: the hosing and identical fittings at either end. The hosing is 1/8" OD urethane line. The fittings are 90º universal fittings with 10-32 threads

Clippard Parts List:
2x UT0-2
1x 1/16" internal diameter polyurethane hose.

Substitution Option:
2x Beswick Engineering MLS-1008-1-303 instead of the UT0-2
Beswick makes the smaller, square swivels with countersunk screw-heads that work just as well as the hexagonal UT0-2 fitting from Clippard, but they don't sell them individually.

Comments

[MFXPYRO]

Hi, what's purpose of using a separate quick exhaust valve rather than a switch with an accessible exhaust port? Is it purely for greater flow rate?

[Crosius]

Partially, yes.

The miniature valves that also incorporate manual controls at that size have lower flow rates than the exhaust valve.

My other reason for using this configuration was to separate the control & the effect by a long distance, while keeping the distance from the air supply to the effect tube as short as possible.

If the effect tube was being cleared by air passing through a long tube from the switch, there would be a very different attack/decay to the effect "burst". It would start and stop less dramatically.

[kanzume]

Hi Crosius, do you think you're able to write up a new and improved version combining what's been mentioned in the comments (e.g. daisy chain, whisker valve, schrader valve etc) with parts readily available on eBay and/or RS online? I'm in Australia and getting parts from Clippard isn't really possible.

Cheers!

[Crosius]

Unfortunately, I'm constrained by budget and time, so new variations on this instructable are always going to be slow.

I know Clippard has limited distribution outside of the Americas. You could try ASCO. They make similar valves and they have distributors in Australia.

[ScubaSteve]

Where might i find all of these?

[Crosius]

 The parts are all available at Clippard's online store (www.clippard.com)

If you have a local reseller like Wainbee, you may want to have them order the parts for you.

If you can't find a local source for Clippard parts, a company by the name of Pneumadyne makes similar products.

[RavingMadStudios]

Well, we're now in tech rehearsals for our little stage production using 8 of these marvelous devices, and I thought I would post a few "lessons learned" type tips that may be helpful for those doing stage work (as opposed to film, which can be more forgiving of "oops" moments).
1. Adding a tee fitting (Clippard # 15002-3) to move the check valve next to the cylinder and substituting a 2-way valve (Clippard # TV-2S) for the three-way valve greatly increases the concealability of the trigger.
2. We have found that using small amounts of poster-tack style removable putty adhesive to seal the hole in the effect tube (rather than the low-tack masking tape), seems to reduce premature blood leakage when the actors have to wear their loaded squib for extended periods before firing it, or when they have to move around a lot onstage before activating the effect. The effect still works perfectly with the poster-tack, as long as you don't use way too much.
3. I highly recommend purchasing extra screw plugs (Clippard # 11755, the same as used to seal the top of the air cylinder) for use as a safety. Actors can be kind of clumsy sometimes, and the last thing you want during a performance is someone accidentally triggering a squib backstage. The screw plug is used to seal the exhaust hole in the toggle valve, and prevents the squib from firing even if the toggle switch is flipped. A stagehand simply removes the plug with a screwdriver at the appropriate time to "arm" the device. You could also use a second toggle valve attached into the trigger line for this purpose, but this would increase the expense a bit. Either way, a safety of some kind is a very good idea.
Anyway, this is a great effect, and it's really giving our production a very polished and professional look. Thanks once again to Crosius for sharing it with us.

[Crosius]

 Blu-tac for plugging the tube is a great idea!

Also, great solution for avoiding early triggering.  Too bad it will only work with the two-way valve, though, as the three-way's exhaust isn't threaded 10-32 and the plug won't screw into it - if I wasn't using 3-ways on my squibs, I'd be using that on the next set.

[RavingMadStudios]

Hi there, it's me again. I was just noticing that the effect assembly in the intro page picture seems a bit different than the one in the rest of the Instructable. Is that a check valve in place of the 1/8" ID hose between the quick exhaust valve and the bulkhead fitting, or just a section of tubing? Also, just out of curiosity, do you know how long the circuit will hold pressure and still fire correctly? As I mentioned in a previous comment, I'd like to use this effect in a stage production, so there could be an appreciable gap between pressuring the device and firing it (probably about 30 minutes at the absolute longest, most likely much shorter). Do you think this would be an issue? Thanks once again for a great design.

[Crosius]

Update on pressure retention: I have successfully discharged a squib a whole day (24 hrs) after pressurising it. You should definitely be able to keep a squib on an actor for a whole scene.

[RavingMadStudios]

Thanks for the update. I built one last week, and after the initial "just playing with it" phase, I let it sit for about 6 hours, and it fired beautifully. Nice to know they can go up to at least 24 without losing pressure, though. I've got parts for 7 more coming in the mail next week. This is a great device, and it's going to make the show look fantastic. I've made a couple of very minor mods to your design: I put in the T (as we discussed earlier) to move the check valve closer to the cylinder, I added a push-fit splice connector to the effect tube to make it easier to fill the tube with blood and banana plugs, and I'm sealing the end of the effect tube with vinyl glue instead of tape. So far, everything works even better than advertised. I highly recommend that anyone who needs bullet hits for a film or show just go ahead and build a few of these. They work very well, and are totally worth the expense. Just do it, you won't be sorry.

[Crosius]

Seven? Sounds like quite the bloodbath. The push-fit connector sounds like a good idea for quick reloading and quickly changing the hose lengths. Are you using something like the PQ-RU1208 from Clippard? (3/8" to 1/4" OD reducer). I'll have to try that on my next batch of squibs.

[RavingMadStudios]

Yeah, I'll actually have nine total (including the first one I made, and an alternate version made from a CO2 bike tire inflator), and we're reloading at intermission to reuse them all in Act II. Plus several "wall splatter" effects to simulate headshots, a garroting, mouth blood packs, a slit throat, and a severed ear. Bloodbath indeed. I'm suggesting that the audience bring tarps. The push-fit splice was kind of an afterthought, but it does make reloading very convenient. It's a straight union, more like PQ-SU12. I got it from Lowe's on a whim while I was buying the vinyl tubing for the effect tube. I like the idea of a reducer, though. I think I'll try that next time. By the way, if you're ever in Statesboro GA, drop me a line. I want to buy you a beer or something.

[Crosius]

Sounds amazing. By far the most elaborate use of these squibs that I've heard of to date.

[RavingMadStudios]

Indeed. Funny thing is, I should really be using 15 squibs, but I had to scale back for budgetary reasons. What makes this funny is that the point of the show is about how violent, vengeful behavior is a Very Bad Thing (tm). The playwright has chosen to convey this message via an orgy of bloodshed. The really funny thing is, it works. Anyway, thanks again. I'll post some pics of the show somewhere when the time comes and send you a link so you can see what your creativity has wrought.

[Crosius]

That's just a brass coupling with 10-32 threads at either end I had around the shop - it has the same function as the short bit of 1/8" tubing with the 1/8 barb fittings on either end, but it is less useful, since the squib is stuck in that "L" configuration. My Squib has held pressure for 10 minutes and worked fine when triggered after that time. I haven't had an application that required a longer delay, so I haven't tried longer than that. The valves and threads seal very tight at 100 psi and I cannot detect any leaks in my squib. How long a specific squib can hold pressure depends on how well the threaded connections are sealed, and how tightly the valve internals seal. If you do find that a threaded fitting is leaking (hold the pressurised squib underwater and watch for bubbles), you can use plumber's silicon tape to seal the threads. If a valve leaks, you can't do much more than exchange it, as the internals aren't serviceable. Even with a slow leak, the squib will still operate properly at pressures down to around 40-50 psi, so you might still have time to pressurise off stage (to 100 psi), wait 20 minutes and then fire a squib that still has 40 psi of pressure in it. The exception to this would be if the QEV is leaking out of the exhaust-way - that would make the stage blood "ooze" out of the squib before it was time.

[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.

[poppamies]

where did you get the mini exhaust valve?

[Crosius]

The valve is a 10-32-threaded, miniature quick exhaust valve from Clippard Minimatic (www.clippard.com) The part number in their catalog is MEV-2. I had a local pneumatic parts supplier (Wainbee) order the parts for me from Clippard, but you can use Clippard's online store to buy directly from them.

[RavingMadStudios]

This is amazingly elegant. I was looking for a compact non-pyro effect for use in live theatre, and this looks to be an ideal solution. Thanks very much for sharing it. One question: Have you given any thought to modifying the trigger to use a solenoid valve, which could then be triggered with an r/c relay? I ask becasue I'm trying to avoid actor-triggering (don't want the audience to see the trigger), and I can't have a control line running offstage. Any reason you can think of that something like that wouldn't work?

[Crosius]

Yes, you can substitute a solenoid valve. The ASCO Series AL valves are miniature (6- or 12-volt coil) solenoid driven 3-ways with 10-32 threads that could be used to trigger this squib. Sadly, they are $75 valves (last time I checked), so they more than double the cost of the squib, even without control circuitry. You'd need an electronic remote that could generate a 6- or 12-volt pulse to trigger the squib. I've been tinkering with a 5v triggered monostable circuit to do this. Unfortunately, I haven't built anything, yet.

[RavingMadStudios]

$75 bucks? Holy guacamole. Add in the RF gear, relays. battery packs, etc. and your elegant, compact and inexpensive design becomes way too bulky and expensive for a cash-strapped theatre company to consider. I think you were right the first time. Maybe actor-triggered isn't so bad after all.... I might still be willing to try it if I didn't need 12 of the things (it's a very bloody play). Oh well, perhaps for another project. Anyway, thanks again for a great tutorial and a beautiful design.

[Crosius]

I agree - that's why I'm trying to solve the problem pneumatically. There are ways to have several squibs go off sequentially with only one trigger event. If you attach the signal line from a second squib to the bottom of the reservoir of the first squib, they will go off one after the other. You can daisy-chain many of these squibs together that way. (eg. machine gun hits) If you splice a "Whisker" valve into the signal line with a "T" fitting, you can make the trigger very sensitive. If you had the whisker sticking out of your actor's shirt-cuff, they could trigger the effect by moving their hand (as when raising your hands). With the addition of a loop in the whisker, you could use a thread pulled by a stage-hand or even an anchored thread that the actor pulled against when he stood on his mark. A slight shift in weight would be enough to trigger the effect.

[RavingMadStudios]

Interesting. I'm not familiar with whisker valves, but I'll definitely check it out. I am assuming that if you T the whisker valve into the signal line, you'd then have two options for firing - the whisker or the toggle. This is just an assumption, but it could be useful if it pans out. As far as the daisy-chaining goes, that could be very useful as well. I may wind up needing a couple of rapid hits for this show, depending upon the staging. I'm guessing something like a schrader valve in place of the solid plug on the reservoir (and an appropriately fitted connector line) would do the trick, with the added benefit of making the daisy-chaining a "modular" option rather than a hard-plumbed design choice. Come to think of it, if there's a schrader valve on the reservoir, couldn't the device be pressurized that way as well, thereby avoiding having to pressurize from the trigger end? This is where my limited knowledge of pneumatic valving comes in, but if the squib can be pressurized from the reservoir end, wouldn't that allow the 3-way toggle on the signal line to be replaced with a simple 2-way valve (maybe just a whisker valve by itself?), and eliminate the need for the check valve assembly altogether? That would be really cool for my purposes, because it would make the trigger assembly smaller, and thus more easily concealable onstage. Or perhaps I'm missing something critical in the valving, and it wouldn't work at all? As I said, I'm no expert. Thanks very much for all your great ideas, and sorry to be such a pain in the hinder.

[Crosius]

A whisker valve is the pneumatic equivalent of a microswitch - it's a 2-way that is sealed when the whisker is straight and opens when the whisker is deflected. You're correct that splicing one into the signal line would give you two triggers. To remove the toggle valve, you'd screw the check valve into one end of the T, the whisker into another, and have the signal line run from the remaining leg of the T. You don't need anything fancy to connect the second squib - the threaded fittings on the end of the signal line screw directly into that hole (you don't use the trigger assembly for the second squib) You can't pressurise the system from the reservoir side. The Quick Exhaust Valve only hold pressure if it is pressurised from the signal-line side. To replace the 3-way with a 2 way (or a whisker valve), you'd need a T in the signal line with the check-valve attached there. The check valve lets you put pressure in, but stops it from coming out. You could put that T very close to the reservoir and tape the check valve to that for neatness.

[RavingMadStudios]

OK, I get it now. I had my brain in backwards there for a minute, I do like the idea of adding the T and putting the check valve closer to the reservoir. I think I'll give that configuration a try, and maybe pick up a couple of whisker valves to play with, too. Based on the specs from the Clippard website, the whiskers might be a little too sensitive for what I need, but it's definitely worth testing. Thanks very much for all of your help. You rock.

[wangxiao]

This is by FAR the best, most elegant design I've seen for a non-pyrotechnic squib. I do have some questions though.

It seems that the UT0-2 fitting costs $11 for one, with a minimum order quantity of 5, so it comes out to five fittings for $55 dollars, approximately. I found that part EA-LB10 from Pneumadyne seems to be comparable (10-32 threads with 1/16 inch barb), but for a little over $2.00 a piece, with a MOQ of 25... so for a similar price, it seems you can get 25 instead of 5. Is this really a comparable part?

Also, I think it would be a nicer design if the 3-way valve that triggers the effect used a push-button actuator instead of a flip-switch. The push-button 3-way toggle valves I found seem to be listed as either "normally open" or "normally closed." My assumption would be that the TV-3S is normally closed, but I'd like to know for sure which one I should buy.

Thanks again for the excellent tutorial!

[Crosius]

I have some of the Pneumadyne fittings and they work just as well. As long as you keep the 10-32 threads and 1/16" barb features, you'll be fine. At the time I built this part, I wasn't too clear on which (NO or NC) to buy, either, so I cheated a bit and bought a toggle switch. When the switch is in the "ready" position, the path from the input to the output is clear, and the path to the exhaust is blocked. This corresponds to a Normally Open switch. When an NO switch is actuated, the path from the input to the output closes, and the output is routed to the exhaust port. Pneumadyne makes a pushbutton 3-way with all three ways threaded for 10-32 - it's their "Fully Ported" 300 series. It would work with this design - with some adjustment. The valve has 3 ports. 1 on the bottom, and 2 & 3 located on the side of the valve body. The signal line (to the squib) would have to be attached to port 2, the check valve would have to be screwed into the _side_ of the valve at port 3 and the port on the bottom of the valve body (1) would act as the exhaust pathway when you pressed the button. One thing you will find with the pushbutton valves is that they require more force to actuate. The toggle valves typically actuate with 6-10 oz of force. The pushbuttons can require 30 to 50 oz to actuate.

[wangxiao]

I see. In that case, perhaps the toggle valve would be best. I am curious, however--suppose I have a situation where it's impractical or impossible for the talent to trigger the effect (ie, 3+ consecutive hits, shots where their hands must be open and in-frame), is there a limit to the length of the signal line which would preclude the possibility of an assistant triggering the effect?

[Crosius]

Not by much. My quick and dirty calculations suggest that adding 10 feet of line will increase the delay in the system by about a millisecond. The person flipping the switch is going to swamp that delay with the variation in their own reaction time. I'd be comfortable using anything under 50 feet of line to control a squib - which would let you trigger the effect from far off camera.

[Crosius]

A few people have had trouble attaching their air-pumps to these squibs, so I've added two pictures in step 4 showing two different ways of filling the squib with a bike pump.

[kanzume]

...great stuff! I saw this on another forum and found this here again -- but anyway that's not my point. So basically if I cut my costs down and use a 2 litre coke bottle with the appropriate adaptors instead of the air chamber (which the coke bottle must be on the ground with longer tubing, and other stuff that cost so much, I can reduce the cost... how much is this whole rig? and which store sell all of these stuff -- I don't want to buy over-the-net (I don't live in US so shipping is expensive) or go to 10000 stores to pick up all these parts... a hardware store doesn't sell all of them under 1 roof (or am i wrong?) -- and they usually sell in bulks e.g. 20 valves (well, I can get shot 20 times in 1 go but that, again, raises the costs).

[Crosius]

I'd be surprised if any general hardware store carried these parts. They're even smaller than the parts that you'd use in a home-shop air-tool system. These parts are classified as "miniature" by the pneumatic industry.

I'd suggest looking for a local pneumatic/hydraulic supply shop (one that caters to the manufacturing or tooling industry) that carries Clippard, Pneumadyne, Beswick, ASCO or Parker valves if you want one-stop shopping. All these companies make 10-32 or M5 fittings and valves with comparable features to the Clippard parts I refer to in this instructable.

If you're considering a two-litre pop-bottle as an air chamber, I highly recommend this tutorial by Indy Mogul on how to make a "Blood Shooter" - it's entirely made with parts you can get at a hardware store.

[kanzume]

Yes, I saw that -- that's where I got the coke bottle idea from, but it can't be actor-triggered. This is why I want to combine yours and Indymogul's together...

[Crosius]

Hmm. So what you really need is a remotely actuated valve to replace the indy-mogul "Blood Shooter's" globe-valve. The Quick-Exhaust my project uses might be a little small for using a pop-bottle as an air reservoir - although you can probably still use the trigger and signal line, you'd probably want a QEV with larger ways and larger threads for the bottle and hose. Something like Clippard's JEV-F2M4 would be a lot easier to screw into a bottle cap, with a 2CP2 (1/6 barb to 1/8 NPT fitting) screwed into the inlet to attach the control line and maybe something like a 12844 screwed into the outlet so you could use some inexpensive 1/4" ID vinyl tubing to hold your stage blood.

[kanzume]

yeah, I liked yours more because it can be actor-triggered with a flip switch. Do you think you can build 1 like that and make a tutorial with the least number of parts required?

[Crosius]

I'll put it in the queue as a potential project.