This project was my first attempt at a pneumatic Halloween prop 2 seasons ago. We got fired up to try this after reading MAKE: Special Edition on Halloween. On p. 80, they describe the whole process in good MAKE fashion. Their instructions are good and the magazine is worth purchasing. Just thought we would share our experience in making the project.
Since it was our first compressed air prop, we opted for the kit from Evilusions.com. They are some great guys and were very helpful.
Finally, this is not an inexpensive project since I purchased a few kits and an air compressor. Since I now have worked with the compressor and components for a few years now, I would feel more comfortable recommending purchasing the components separately and more cheaply.
Materials (Total around $300 or so; could be cheaper if you follow many articles on the web about the pneumatic components and purchase them directly and reuse some old Halloween props):
- pneumatic popup kit: http://evilusions.com/shop/product_info.php?cPath=71&products_id=914 (shows $200 now)
- prop head: http://evilusions.com/shop/product_info.php?products_id=580 (about $50)
- trash can with lid, we used a gray plastic one (about $50)
- a few lumber scraps to build the base, we used 12" or 2x4 and 2 pieces of 12" 2x6, this will vary for your can and angles you use (less than $10)
- wood screws and washers to mount the base in the can, additional screws to make the base and fasten the pneumatic controller and piston to the base
- additional decorations for the pop-up dude...some creativity required here. we -reused an old static prop
- paint and stencil for the can. we used fluorescent green paint and a Powerpoint stencil cut out with Exactos.
- saw to cut scraps for the base
- drill or something else (knife) to punch holes in the trash can (MAKE's project used a metal can)
- screwdriver and wrench/driver
- this project requires an air compressor. I was able to find a sufficient one at the Depot for under $100.
Step 1: Make the Base
When you make the base, you will need to test the height of the base in the can along with the pneumatic cylinder to make sure when it is mounted, the cylinder's rod can extend and clear the mouth of the can. It will probably be helpful to mount the prop's head for this test. You can see what I mean by the mount angle in the second picture.
Its probably worth mentioning that since i bought the prop head from Evilusions, they provided a threaded mount to match the end of the pneumatic piston. Don't forget this if you use your own prop.
Step 2: Mount the Pneumatics
The first photo shows the control circuit and relay. The most important point here is to make sure that there is enough clearance for the air compressor hose (the silver connector in the center). Keep in mind that the hose will be snaking in through a hole in the back of the can and up to this coupling. FYI the 2 brass couplings are exhaust ports.
Also needing some clearance are the two couplings with the purple tops. These are where the two control hoses go that operate the piston. In the kit there are small black plastic hoses that are used and the couplings are really easy to use - just push the hose into the plastic fitting and it locks into place. To remove it, press down on the purple collar.
The second photo shows the cylinder mounted and the control hoses connected.
Step 3: Mount the Base in the Can
Here again you will need to test the positioning of the base to allow the piston to clear the mouth of the can. In the second picture you can see that I got a little crazy fastening the base to the bottom of the can (this is a view of the outside bottom). I wasn't sure how violently the piston would shake the base so I wanted to be sure. This turned out to be sufficient.
I didn't take a picture of it but this would also be the time to figure out what the front and back of the can will be and to mark and make a hole for all of the cables and hoses. My hole is about 2 " square. Some things that people put in their cans in addition to the pneumatics include:
- black/strobe lights
- fog machine (small one) or a feed tube for fog
Keep this in mind when you plan your hole(s).
Before screwing in the base, you will want to get all of the cables, wires, etc connected so that you don't have to spend too much time with your head in the can later. This includes:
- attaching the controller tubes
- attaching the power cable to the pneumatic controller (mine was a wall wart with bare wires at the other end)
- pneumatic controller switch (mine was a simple pushbutton controller attached to 20 ft of lampcord)
- you may want to put a small power strip in there too if you are adding other items mentioned above
Step 4: Construct and Decorate the Prop Head, Etc.
Instead of just using the prop head (his name is Earl)...we decided to add a little more decoration. We took apart the shoulder assembly and some of the gown from an old prop (second photo) and attached it to the piston/head for a more realistic effect.
In this step, I would also recommend fastening the trash can lid. I punched two holes at the back of the can and rear of the trash can lid about 4-5 inches apart. I then threaded each of the corresponding holes (can - lid) with a large zip tie and tightened about half way (to be tightened later during testing).
Step 5: Paint the Can
We decided on a toxic waste theme and made a stencil in Powerpoint and cut the letters out with an Exacto knife. Then we taped the stencil on the can and used green fluorescent paint.
After the painting the can looked a little too pretty, so I liberally oversprayed most of the front and top of the can to get a messier effect. This looked a lot better with the black light.
Step 6: Test and Adjust
Understandably I don't really have any photos for this step. Here was the basic process:
1 - attach the compressor hose (through the hole in the back of the can)
2 - get the compressor started (you will need to get the advice from the compressor manual and the manufacturer/supplier of the pneumatic controllers regarding the pressure settings)...start at the low end of the settings in case you have clearance problems with the prop head
3 - test using the push button
4 - test fittings of any hoses if the piston is not firing (one time i had the hoses reversed between the controller and piston and the "off" setting of the button kept the piston extended...so just swap if this happens)
4 - adjust and note pressure settings
5 - retest
6 - adjust prop head and any other decorative stuff to your liking.
7 - adjust can lid to make sure the zip ties are serving their purpose as a makeshift hinge; tighten or replace zip ties as needed
Step 7: Set-up and Enjoy
A few other notes:
- I tested lights inside and outside and think the inside light is overkill and prefer a black light and maybe a spot/strobe
- I had to replace the pushbutton controller (cause i pirated it for something else) and just uses a pushbutton from radioshack and some speaker wire. worked great.
- with the small compressor, we get about 10 firings before we have to turn the compressor on (noisy). just wait till there is a lull in the action.
Kids love this thing and my boys love activating it.