# So you want to build a pneumatic prop?



## SkeletalRemains (Jan 14, 2006)

I just wanted to toss this out and see who was interested. (If enough people are interested and respond to this thread, I will post follow-ups with pics on how to hook up everything you need to run the pneumatics from the solenoid to the cylinder.)

I noticed that so many people are interested in pneumatics, me too!

You see, I love Halloween and haunted houses (like all of you), and have for a number of years. Many years ago, I was scouring websites looking for ideas and how-tos on building pneumatic props. I built a few out of knick-knacks, spare parts and lumber around the garage, screen-door closers, etc. But I spent a TON OF MONEY trying to build just a few props because I had to see with my own eyes what worked and what didn't. I really tried to modularize this whole 'pneumatic prop' thing in my head, but could never do it. 

Fast forward several years later, and I am proud to say that I am now the lead tech at a huge haunted house in North Texas. I owe a lot of people for that title, especially since I really had to pay close attention when opportunities arose, learn a lot on my own, and take initiative when required. You wouldn't believe what I have to go thru in October when we are operating. As October is always fun, the off-season is what I love, and can't wait for, since it feels like I now have a clean slate to work from.

For example, a few years ago, I built my first drop panel, and it broke the first night. I fixed it and it broke the second night, and the third, fourth,etc...mainly because I hadn't figured out what worked. Now through that experience, I have a design that often lasts all season without breaking once, and we're talking about 5000+ drops. (And I can make one in about 2-3 hours, when the first one took me 2 days)

The same idea with props, I learned what works and what doesn't, and it has really elevated my level of expertise with these devices. I thought I was the rookie, but it turned out that all of a sudden, I knew more about pneumatics than most of the people around me. All in all, it really is simple, it's just that it is often difficult to wrestle these secrets away from the haunt pros, so every major yard haunter in the nation (and there are probably hundred's of thousands if not millions) has to spend a fortune at home depot for trial and error, and since most yard haunters only operate one night a year, there isn't enough practical test time to learn all of this and troubleshoot stuff and try new things, etc...

Anyway, I am including some suggestions below for anyone that wants to make their first pneumatic prop for their haunt this year, based on my experience. This is some of what I have learned over the past few years working on pneumatics in a pro haunt:


1. Pick just one single-action prop to build, and get it straight in your head exactly how you want it to work, and forget everything else. Multiple-action props typically require controllers (brick/minibrick/parallax/etc), and you do not want to try to tackle a complex prop the first time around.

2. Sketch out your prop on paper to the best of your ability (even if you're not a great artist, I especially am no artist...). Use your tape measure to get ballpark lengths of each piece and how much material you will need. Draw in your pneumatic cylinder wherever it makes sense, don't worry about what length, type, etc. Too many people just buy cylinders and MAKE them fit a prop no matter what, which can be done to an extent in my opinion, but this can easily be taken to extremes. Use pictures of props on the web to get your general design, there are plenty of ideas out there.

3. Go to home depot or lowes and get a couple of those yardstick-sized paint stirs, and a cheap little box of nuts and bolts, the small kind... You can build a replica from this material to test the actions of your prop mechanism. Just cut the stirs with a little saw, and drill a pilot in the ends and bolt it all together. If the holes aren't right make another hole and test it out. You don't have to build the whole base, etc, just enough so that you know how the mechanism will work and if it is working to your expectations. Make sure that the 'math' as it applies to leverage is reasonable, and that the cylinder is positioned in a way so that it doesn't need 100psi to get the first 3 inches off the ground, and then only 35psi the rest of the way. The cyl should have relatively equal load throughout it's stroke.

4. Decide on material. OK, here's where it get's tough. To be honest, nearly every commercial prop is built out of steel and welded, but it's not realistic that each person who wants to build a prop is going to know how to weld or even have a welder or a facility to use one. So, a good hacksaw and a box of stainless 3/8" bolts, washers, and lock nuts is the next best thing.

5. Put together a budget for this thing. You already spent 7-8 dollars on stirs and small bolts, but here is where you need to make a commitment on cost. It will probably cost you about $100 to build a reliable, reasonably-sized prop, give or take, depending on how good of a deal-finder you are on eBay. 

6. Buy the parts, build the mechanism. This really isn't that tough, and pretty much anyone on here can do that.

7. Pneumatics, this is the fun part. OK, go out and find a suitable cylinder on eBay. Get a Bimba or SMC or other good brand. If your drawing shows your cyl mounted in the back, go for a pivot-mount cyl, if it mounts in the front, go for a nose-mount cyl. A lot of times you'll find one cyl that has both mounting options.

8. If you're making a pop-up, you can probably use a 3-way solenoid valve no problem, since the prop will come up at the same speed it will come down. If you're using a lifter or popout, you may wany to use a 4-way solenoid valve, which will allow you to adjust the rate of descent of the prop differently that ascent. This is great for props that pop fast, but need to reset slowly as not to come slamming down so hard. You can find these on eBay pretty easy. MAC or SMC makes them, as well as ASCO. Just search on eBay for those names under the Business/Industrial Supply, and stay away from pilot valves, as they are air actuated and defeat the purpose of an electrical trigger.

9. Use polyethylene tubing with push-in quick-connects, not barbs. Lowes carries the quick-connects now but they are pricy. Instead check out poweraire.com and find instant-fittings. They are cheap and ship fast. The tubing is $7.50 for 100' any color for 1/4" O.D. tubing. Make sure you buy all 1/4" fittings for the tubing, and most likely either 1/8" or 1/4" for the solenoid fittings.

9. Run triggered power to your solenoid. Whatever the voltage on your solenoid, use a piece of PVC, and a pushbutton switch from Radio Shack, workes great every time....

10. OK, whatever else you want to know, just post in this thread and I will try to help you out with anything I can. All of the people here are so nice and offer so much assistance, so I just want to do the same. What can I say? I love working on props...

And since you read all the way throught this long post, I have included a pic of one of our ScareFactory props below (actually it beongs to our friend Gary, another pro haunter). You can see me on the left with my hand on the dog's butt. (holding him up while he's broken) I fixed him up and he jumped thousands of times this season...


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## zeenon (Oct 28, 2005)

Awesome POST!!!!!

I have not built a pneumatic prop but would LOVE to. From my stand point (a beginner when dealing with air) the hardest part has been parts and fittings. There is no clear tutorial that tells you which parts to start with. Most say goto ebay and pick up a 6" cylinder and an ASCO Red Hat valve. For a beginner this is a scary task because of all the options and no one wants to buy the wrong thing. It would be nice if someone put a parts list, along with which online vendor carries the parts. 

Another factor is what is available in one persons home depot may not be available in another section of the US. As an example there are a lot of great tutorials out that use a dish washer valves or sprinkler fittings, which I've seen is a PITA to come across.

Lastly, price. I have a couple of bimba cyclinders (short stroke though) but I opted to try the plans for a PVC manifold and screen door closer. Once I see it operational I have no problem switching to industrial cylinders and MAC/ASCO valve but can't see laying out the initial cash for top of the line stuff until I see the fruits of my labor and get a basic understanding of pneumatics.

I know there are two camps on using PVC/door closers vs. bimba/commercial valves so my intent is not to start a thread war on this subject. The debate comes up every season so if you feel the need to rant, go find an old thread. On the other hand there are several people using door closers and several using bimba cylinders. 

I think this is a good start.....

Z


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## Mage (Oct 20, 2006)

Great post, very informative. On that note, pneumatics is for wimps, hydraulics is where its at


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## SkeletalRemains (Jan 14, 2006)

*hydraulics*

Hi Mage,

You're right, hydraulics *IS *where it is at. You can move mountains with hydraulics!

I haven't worked with any haunt-related hydraulics (never found a need to yet!), but I have worked on pumps and reservoirs as they apply to dancing truck beds from years ago. They are pretty cool, and I actually now wish I still had a few of those hydraulic pumps laying around, they were all 12vdc and packed a lot of power. I bet I can still find some, somewhere....

Hydraulics is an expensive hobby though, and takes a bit more knowledge than knowing air systems. 

Hey, if you want to cover hydraulics the same way I am planning to cover pneumatics, that would be great!

*So, anyone who has questions or wants to see something specific, let me know and I will tell you whatever I know, if I know anything!* I will try to get some pneumatic stuff up on this thread tonight...


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## nOrTHeRn TouCh (Feb 24, 2006)

right On!!! Wicked post I been searching and reading all the info that I can on pneumatics and still was loking for more info before I start great thread hope u keep it going....


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## SkeletalRemains (Jan 14, 2006)

*Oh yeah...*

I will get some of this stuff up tonight hopefully, so check back. And by the way, that pic up there of the dog, I am not giving him an exam, just wanted to show him in the extended position!


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## nOrTHeRn TouCh (Feb 24, 2006)

LoL that's great lol......looking forward to seeing those pics and how too's...I wouldn't mind seeing how u do your drop panel as well...


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## SkeletalRemains (Jan 14, 2006)

*Drop panel*

Hey Northern, funny you should mention the drop panel. You're not the only one who wants to see it. Leonard Pickel asked me to write an article on my drop panel for Haunted Attraction mag. Funny thing is, I revised it again this year and so the article is actually a little out of date now. But Leonard came out to our haunt in June (came out to be keynote speaker at our haunt dinner)

I don't know how much I will actually get up there tonight, but the good news is that I'm headed down to the haunt tonight to take pics of some of my stuff. I will also get pics of some of my air cannons as well in case any of you want to build one yourself.


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## Dr Ghastly (Apr 13, 2005)

Having recently been a pneumatics newbie, I recall most of my dilemmas had to do with connectors (which ones and where to get them) and how to select the appropriate compressor/storage tank.


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## nOrTHeRn TouCh (Feb 24, 2006)

Dr Ghastly how di u go about overcoming all those problems? I want to buy a comppreser but what is good to use(Hp/gallons how many)what do i need to get started....


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## dionicia (Nov 5, 2006)

This thread is great. I am eager to learn for next halloween. Both the drop panel and the pneumatics props. Would it be possible to do pictures with the instructions for both?


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## ruafraid (Oct 5, 2005)

Hey count me in! I am always looking to learn more and my welder feels neglected.


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## SkeletalRemains (Jan 14, 2006)

*Some pics*

By the way, you can easily use a 5HP 20gal compressor to run your props. Unless you have 5 air cannons running off this compressor, you'll be ok up to about 5 props, give or take, maybe more if you're using low pressure props.

OK, don't kill yourself, compressed air is dangerous! I am not repsonsible....

First, a cylinder primer...

You basically have two major types of cylinders available for haunt uses. I will classify those as single-acting and dual-acting. A single acting cylinder is like a screen door closer, air only moves one way through a single port, and a spring retracts it when air is removed. A dual-acting cylinder has two ports, one on each side of the piston rod end, and air is reversed back and forth thru those ports to activate and reset the cylinder's extent.

Next, a solenoid primer...

1. An air 'valve' is a typical manual/hand operated air cutoff. When you turn it on manually, it lets air thru, when you close, the air stops going thru.

2. An air 'solenoid valve' is an automatic valve that is operated by an electrical solenoid (coil).

3. An air 'pilot valve' is an automatic valve that is operated by another air source. When air is applied to the pilot valve, the valve activates. Think of a pilot valve as a relay for air instead of electricity. You can use a small pulse of air to control a larger source, just like a relay.

For Haunt purposes, I suggest sticking with solenoid valves. 

Now, please note that solenoid valves typically have a single coil, which is reset by a spring when deactivated. But valves do exist that have coils on each side of the plunger. You can still use them, you just need a relay wired up to use them correctly. But again I suggest you stick with single coil solenoid valves if possible. (if you need help with this, let me know)

All the time, people ask me the difference between 2-way, 3-way and 4-way valves, so here it goes. Figure out what application it wil serve first. If you want to vent massive air toward the feet of patrons (air cannon), you get a 2-way valve, because a 2-way valve has 2 ports, an air inlet and an air outlet, and air only travels one way through the valve.

Now, if you want to build a prop that moves an arm back and forth along the same plane, and it moves the same speed when extending and retracting, then use a 3-way valve (4 ports) with a dual-acting cylinder (2 ports). The solenoid has an air inlet for source air, then two ports for running the cylinder, and one more port for exhaust. Even without the valve triggered, the cylinders will go to their 'home-state' when air is hooked up to the valve. This causes the prop to seat firmly when not triggered. As the prop is triggered, the source air redircts to the other line and floods the other end of the cyl with air, causing it to reverse it's position. But where does the other air go that was in the cylinder? It changes direction and goes back through the solenoid and back out the exhaust. Because of this, you cannot adjust the airflow differently for extension and retraction.

Now, if you want to adjust the airflow independently on each side of the cylinder, use a 4-way solenoid (5 ports), which is the same as a 3-way, except that each line to the cyl has it's own exhaust. Then you can adjust the airflow differently and cause the pop and reset to occur at different speeds. This is good when you have a prop that needs to popup fast, but reset slowly as not to cause damage. Here is a prime example of what I am talking about:



Here is your typical 4-way solenoid. Notice that there are only 3 airtubes going to it, that's because I didn't take the time to hook up exhaust tubing, which will make it much quieter and get rid of the SSHHH sounds... the tube on bottom is the air source, coming from a regulator, which in turn is plugged into the air compressor. The two lines on top go to the cylinder. There really are 5 ports there, just can't see of them because they are on the bottom by the air inlet port.










Do you see the little connectors I am using? Those are 'quick-connects' or 'instant-fittings', depending on where you buy them. I paid 63 cents each for those that go straight out from the solenoid. They are 1/8" NPT threads and adapt to 1/4" polyethylene tubing. The tubing costs $7.50/100' roll. The pic below shows the same type of 1/8" NPT thread fittings but at 90 degree angle. These were 87 cents each. Make sure to buy the right ones based on what your solenoid needs. Get these fittings at www.poweraire.com.










Above is a dual-acting cylinder. Can you see why? No spring involved, air pushes it back and forth. It will stay either extended or retracted until the solenoid is activated, then when activated, will reverse, and when deactivated, will return to it's previous state. Is this making sense? Good! If not, post some questions. Is this helpful?


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## zeenon (Oct 28, 2005)

Skel,

What kind of solenoid is in the picture?

Can you recommend a place online that sells solenoids?

If I have a Sears compressor with a regulator on it, do I need a regulator if I'm only running one prop? and for those that run more then one prop, what kind of regulator do you use?

Z


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## dionicia (Nov 5, 2006)

This is great. Do you have any picts of the drop panel?


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## dionicia (Nov 5, 2006)

I have another question. About how many uses can you get out of an average home compressor tank on a prop before having to refill the tank with air?


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## SkeletalRemains (Jan 14, 2006)

*solenoid*

This is a Numatics solenoid Model 031SA4412. It has a max pressure of 150PSI and uses a 110VAC coil. As far as finding one online, it is usually better to just find a similar solenoid on eBay, since there are so many types and model numbers. Usually we haunters just have to find a close one for cheap and adapt to it. If you want to just go out and buy one though at full price, feel free! This one new is about $55.50. Sometimes we just pay full price for stuff if we're in a rush, and don't have time to look for cheap deals.

Find it here: 

http://www.plccenter.com/buy/NUMATICS/031SA4412000030

And if you have a regulator on your compressor and only running one prop, then you don't need another one. If you do want to run multiples, find a cheap regulator at home depot in the tools area for about $15. You might get 20-30 pops on your mechanism depending on how much air it uses, what PSI, how much leakage, etc, before it cycles.


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## SkeletalRemains (Jan 14, 2006)

*Drop panel*

OK, I am going straight to hell for revealing my secret, but here it goes...

Here is the front as it stands painted...like a picture with a frame...










Notice anything weird about this painting?










Here is the back, kinda tough to make it all out, but it's all there...










Notice the 'T' on the right, that is my big secret to reliability....what you cannot see is the notch in the 27"x27" square piece of plywood. The window itself is 24"x24" square. The slides on each side are simply 2x4s with a portion cut out of the other side that allow the plywood to travel in the groove. There is an additional cutout in the right slide to allow the 'T' to catch the panel. The 2x4s on the back of the plywood are for stability and girth, and a bigger bang!

Here is one more pic that shows the panel to the floor...


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## dionicia (Nov 5, 2006)

That is so cool! I can wait to build one for next year.


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## nOrTHeRn TouCh (Feb 24, 2006)

Thgis tread is freaking great!!!that drop panal is just wicked I love the linkage that was a problem I had ran into with my drop panals...As for the the rest of the post I still a little confused but I find my self learning but not being able to put all this info togeather and to try and build a prop...


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## Bucky (Oct 15, 2006)

Excellent post, thanks for the pneumatic lesson.

This year I picked up a prebuilt pneumatic based off a storm door closer on Ebay for $60. The prop was sold new, but 1/2 what it was before halloween. I figured the best way for me to get into it was to pick up a cheap one first, look it over play with it and decide how I can improve it. 

So over the next year I'll be able to learn everything I need and hopefully have a good haunt next year. 

This year I only did static props, some signs, mud monsters, simple stuff. This afternoon I built my first toe-pincher coffin. Why? I found a bunch of old picket boards next to the house that needed use. So now I have a coffin my bucky can sleep in. Nothing fancy, just a cheap old looking coffin. 

What I am looking to build is the "Body Slinger" (http://www.scaryguys.com/slinger.htm) that I found on the internet. With the help from this post, a few Home Haunter Handbooks from Steve Hickman and my new prop to disect, I think I'll be able to do this.

Funny thing is I work for a Valve company in IT. So I go through the factory and see all these solenoids, pilot valves and such but never really had a use for them. Now I have an unlimited supply of valve engineers to help me out. Next I will need to figure out some good triggering devices such as motion detectors, and some sound loops. To me, a prop just isn't as effective without a good scream.


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## SkeletalRemains (Jan 14, 2006)

*pneumatics*

Hey Bucky,

I will get more stuff into this thread pretty soon. I have just been working catching up from everything I neglected in October, like work! I worked 70 hours last week and am headed for about 90 this week, so I'm getting home VERY late each night.... I still have my welder and all my tools in the trunk and back seat of the car...

Anyway, the 'standard' (if you will) for commercial prop accessories looks something like this:

Actual Prop
Pneumatic Cylinder(s) - Bimba, SMC, MAC
Solenoid Valve(s) - Asco, SMC, Numatics
Pneumatic Accessories (air tubing, quick connects, adapters)
Prop Controller (Gilderfluke brick, Parallax Basic Stamp, UDT)
Sound Chip (Cowlacious, Gilderfluke, etc)
Trigger Mechanism (photoelectric sensor - omron, PIR motion sensor)
Amplifier (Peavey, Marshall)

These are the things you typically get when you buy a ScareFactory or Distortions prop. Of course, the trick is how to make all this work without spending a FORTUNE on it! That is the trick. If you buy everything above, it can EASILY surpass $1000 for one prop, that's why props are so expensive when you buy them from a commercial prop house. Things like the BooBox from fright ideas is about $500, which encompasses everything except pneumatics and amplifier. And of course Gilderfluke has a new brick controller that has a 50W amp built into it for around 200-300 bucks.

But, if you want to make it cheap, there are lots of tips and tricks you can use, and it is what I want to share in this thread. As soon as I get more of a pneumatic primer together with pics, I'll post to this thread. Hopefully that'll take some of the guesswork out of prop building for a lot of newcomers...


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## Bucky (Oct 15, 2006)

OK, I've got started and things are coming along great.

I managed to start off with a sample cheap prop. I used a storm door closer, hooked it up to a regulator, passed it through a water inlet valve which I connected to a quick connect to an air tank. 

so far, not bad. The water inlet valve doesn't seem to be closing properly. Air is passing through even when the valve is not plugged in. Since it was a new inlet valve I must assume it is some problem of mine.

I did happen to pick up a Bimba cylinder. Its dual actuated, 6" stroke, with 1 3/4 bore on it. I would like to go professional with this one and use a real solenoid so I think I'm going to pick up the one you have shown in your photos. 

I get most of the concepts and as I play it becomes really easy to understand. What I don't know is the electricity at this point. If I pick up that solenoid you have listed, where can I find a plug that hooks into it. The 3 prong you have on there looks like I need specialty connection. And does that hook into a standard 110V outlet. Guess I'm wondering do I need that connector or can I use an extension cord spliced with electric connectors on it?

I'm loving this. It was exciting to have everything fire off this morning. To bad there are leaks, but the concept has been proven.

I'm willing to pay for the right parts over salvage at this point to get it right. Besides I'm just building up inventory.


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## Guest (Dec 5, 2006)

Bucky said:


> OK, I've got started and things are coming along great.
> 
> The water inlet valve doesn't seem to be closing properly. Air is passing through even when the valve is not plugged in. Since it was a new inlet valve I must assume it is some problem of mine.


If you're using a washing machine water valve, Sounds like you may have the lines on the wrong sides of the valve. Make sure your air is going into one of the two large connections from your compressor, and the line going into the props is on the small single barb on the side of the valve. I've made that mistake before. Hope that helps.


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## Bucky (Oct 15, 2006)

Awesome, thanks for the feedback. That was the problem. I guess my make shift instructions weren't very good.

Anyway, I reversed the connections, found that my crummy $.01 regulator on ebay has serious leaks and is really garbage. So I got a Husky regulator from Home Depot and now I'm in business. Everything is working very good. I've added some quick connects and this baby is ready to scare some kids. 

Nothing like getting this excited over a pneumatic prop in early December. Now I can start on the other 6 projects I have for this year.


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## dionicia (Nov 5, 2006)

You've gotta post some picts Bucky. I for one am excited to see your progress.


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## Bucky (Oct 15, 2006)

I'll try to get some pics up later this week. I've actually got to into work a couple of times this week.


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## SkeletalRemains (Jan 14, 2006)

*More stuff coming...haunted dresser...*

Hey, just wanted to let you all know that I have a lot more stuff to post in this thread, but I have been really busy with work lately!

I did manage to get some cool stuff off of eBay lately and will be posting more pics and other stuff into this thread.

Sorry again it has taken so long, I'm still catching up from all the stuff I didn't do in October while we were running the haunt!

But, my son recently decided he wanted to get rid of his dresser and get a leather couch in his room, so now I have a 14 year old dresser with no future in my garage, so I am breathing new life into the dresser as a new animatronic prop...

My vision is to have all the drawers rattling in and out randomly using pneumatics. This should be fun...I'll post all of my progress from beginning to end on it...


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## Gym Whourlfeld (Jan 22, 2003)

The electrician down the block from me was selling me new washing machine valves very cheaply, then one day he decided to just throw away all of the valves he had left???
I have found some lawn watering valves at Menard's for about $9.00, they are rated at 150 pounds pressure, are threaded taped, one inch so threaded reducers are needed but they operate on only 24 volts, so far they have worked real well for me.
I wired them to a Honeywell heating Ac relay (used) so one click from a remote control held in my hand and the normally open circuit closes, the normally closed circuit opens by powering 120 volts to the relay , which switches the opposite valve to the opposite position effecting a "Closed"-"Open" change sending air while closing the exit route, kill the power it reverses , closing the incoming air, opening the exhaust route valve.
This all makes a very new, large, SMC cylinder quietly lift me straight up into the air 20 inches as I hold a small flashlight under my chin, at the top of the lift , the flashlight goes off and some people think I went right up throuigh the ceiling!!
Are we having fun yet? YES!


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## SkeletalRemains (Jan 14, 2006)

*valves*

Hey Gym, are you going to Chicago for the TW Halloween show in Feb? I figured since you are fairly close, it's easily within driving distance, even for a day trip...

I will be there staying across the street at the Crowne Plaza. Let me know so I can introduce myself and we can talk shop for a bit. I'll send you my cel # if you'll be there.


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## Bucky (Oct 15, 2006)

*Some pics of my first pneumatic prop*

Ok, I took a couple of pics of my prop showing the relaxed state and the triggered state.

It's very simple and basic, hope you can see what is going on through all my mess. I've been working on my table saw doing this project so I have tons of parts, pieces and stuff laying around.


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## SkeletalRemains (Jan 14, 2006)

Bucky, that prop is nice! I have some more stuff on solenoids I am going to post tonight, but I just keep getting more ideas on things to add to it.


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## SkeletalRemains (Jan 14, 2006)

OK, if you are watching this thread, I posted a new thread tonight here: http://www.halloweenforum.com/showthread.php?t=60277

I started this new thread so that others could get to it easier, and so that it would be the first post in the thread.


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## Grimsby (Sep 26, 2006)

Great thread - lots of info!
Quick question for Skeletal Remains - do you have a quick diagram of the dog prop in your first post? That's exactly what I want to build for next year! And did his mouth move as well?
Thanks!


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## SkeletalRemains (Jan 14, 2006)

*Animatronic dog*

Grimsby,

The dog's mouth does move. His outer skin has to be removed to see any internal skeletal structure, and we hope to do that probably in April or May, as it is a big task, especially as he is bolted to the concrete floor in a corner, inside the haunt. 

The apparatus is somewhat flawed (in that it requires custom heavy-duty springs to activate that I cannot find anywhere, except ScareFactory) in it's design where the dog lifts, because it is not weighted properly and requires too much spring assist given the length it must travel. I'll try to put something together on it and maybe you can help design a better dogtrap. This prop wasn't built by me, it was built by ScareFactory, but I'll be happy to illustrate as much as I can on how it lifts.


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## Grimsby (Sep 26, 2006)

Great! No need to pull the skin off - I can animate the mouth easily with a 20rpm DC motor linkage I found. I was planning on using something similar to the prop mechanism shown by Bucky, on a larger scale. I liked the design of the supports being disguised as legs.
I can hide the counterweight structure in the 'doghouse' such that you only see the first 3/4 of the beast.


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## SkeletalRemains (Jan 14, 2006)

*Please note, new addition to the pneumatic primer*

If you are not following my OTHER thread, please check it out below, I have added Part 2 of the pneumatic primer to it.

Enjoy!

http://www.halloweenforum.com/showthread.php?t=60277


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## djm902 (Nov 30, 2006)

*need some info*

does anyone know if stc solenoid valves are any good?


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## SkeletalRemains (Jan 14, 2006)

*STC valves*

STC valves do pretty good. They are knock-offs of SMC, but in haunt apps they don't really need to be as reliable or as sturdy as the ones used in industrial automation...

So, I would say give them a shot! I use them and they work good for my needs...


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