– Pop Up Prop

Pop Up Part 1

Pop - Up Mechanism

Originally posted on (RIP)
image002Here it is… at least the start of it.
This is a front view of the simple
pop-up stand, my version of a
homemade PVC air cylinder, and
the upper – body frame for this
This is the “shoulder” part of the prop.It is nothing more than a 3/4″ PVC”cross” with two 6″ sections of 3/4″ PVC .
I glued a 3/4″ dowel inside the whole length.PVC cement works fine here, but I could have used 2 part epoxy, or Polyurethane Glue.
It foams and expands slightly as it cures.
image006This is the Four Bar Linkage that
will move the arm.
The 4″ “Ell bracket” in the upper
right hand corner acts as the
shoulder blade.
The vertical bar on the left will
be the forearm. I used 1/8″ x 1″
aluminum flat stock for the forearm
and “biceps.”
Since the lower bar will be doing all
the work, I used 1/8″ x 1” steel flat
After building it, I think it was kind
of over-kill.
I assembled each joint with a 1/4″ x 3/4″ hex bolt.
I inserted a 1/4″ x 1″ fender washer between each moving part.
I used a 1/4″ washer and locking nut.
This makes the joint stay together, but remain loose enough to move freely.
All of the extra holes in the “forearm?”
By using a different hole here, you can adjust how far the arm stretches out, instead of simply shooting up.
I know there is a mathematical solution for all of this, but:
1. Math was not my strong point in school.
2. I like the idea of “adjustable.”
3. Four more holes… no big deal
Here is the shoulder with both arms attached.
When the prop is at rest, both arms will be in the lower position.
It’s hard to see here, but the arms are attached to the shoulder so that they will extend at about 45 degrees, not straight up
image010If you look at the 3/4″ PVC “cross,” you
can see that the head will attach at a
right angle to the cylinder.
By doing this, I hope to build the
shoulders up, similar to the “hunchback
In this photo, it is easier to see the angle I mentioned earlier.
This is the backside of the prop. (left arm.)I can still pull straight down on the arms and cause them to extend.
The 45-degree angle doesn’t interfere.I suppose I could have used a pulley on each shoulder, and had each arm stretch straight out, but I think this will look better as the prop jumps .
image013I applied expanding foam to the inside
of a latex mask, thin layers at a time.
About mid-way I inserted a 3/4″ PVC
“tee” with a short piece of pipe sticking
out the back.
I inserted this into the front part of the
3/4″ PVC “cross.”
I didn’t glue it, and I probably won’t.
I will, however, drive a screw through
the joint.(I can change heads next year.)
There is one more thing I should point out…Directly above the “elbow,” I added an extra bolt and 4 washers.This acts as a limiter to how far the “elbow” folds.
Putting the bolt here ensures that it will not interfere with the movement of any joints.
I hooked everything up and tried it out. The prop lifted SLOWLY at 10 p.s.i.At 25 p.s.i., this prop reaches full height in about 1/2 second.
I’m sure the weight of the body will slow things down a bit.I used two 60″ bungee cords, one on each arm.
They act as anti- spin devices; otherwise, the prop may turn itself around after a few firings.
Also, by using two different cords, I can adjust the amount of pull applied to each arm independently. ( more adjustment.)
Finally, using two separate cords, I was able to form a tripod- like support system at the base. At full extension, the arms reach over 6 feet, so it may become unbalanced with only the cylinder holding it up.

The bungee cords will do a fine job of keeping everything in line.

Pop up part 2

Building A Monster

I finished building his chicken wire exo-skeleton.
I left large areas around each arm open.
The linkage needs a little over four inches of room for travel.
I added two short pieces of 1 1/2″ sch. 40 PVC to the lower portion of the torso.
These act as guides for the bungee cords. They keep everything straight and protect the cords from getting snagged on the wire.
image017Here is a better picture of the finished
wire body.
I made short “tubes” of chicken wire
and attached them to each part of the
arm, making sure nothing would
interfere with the arm movement.
The gaps at the shoulders and elbows
won’t be visible once the prop is
So far everything has progressed
The only real problem I’ve encountered
at this point is forming the chicken
wire torso in a way that it will not make
contact with the stationary portion of
the cylinder.
I solved this problem by cutting away
the center, bottom area of wire that
would be considered the “abdomen”.
This is the prop so far.I started with a simple pop–up frame, consisting of an air cylinder mounted to a metal frame.
I used a home–made PVC air cylinder with this prop.
This prop was decommissioned after it’s 2002 debut.
Even though it performed properly, the use of home-made pneumatic cylinders (p.v.c. or otherwise) is a practice that has been completely abandoned by us at Vile Things.
image021This is the control set up I’ll use with this prop.
(I apologize for the poor quality of this image.)
This is an ARO solenoid valve, purchased from
Grainger for entirely too much money.
I added a pressure regulator before the inlet.
I purchased this regulator from Harbor Freight
Tools for about $6.00.
This model includes a gauge.
I decided to add a regulator to each of my
pneumatic props.The price is right, and this an
easy way to fine tune the performance of each
I can charge the main air line with a higher
amount of pressure, and adjust each prop
This will certainly save MANY footsteps while
the Haunt is up and running.
This shows the prop at full extension.
The top of his head is now about 5 1/2 feet from the floor.
The arms extend slightly out and slightly forward.
They reach up about 16 inches. After I add the hands, this prop should reach a very proud 7 feet tall.
image026I decided to make the robe for this prop out
of landscape fabric.
This is a "non-woven" weed barrier. Besides
making a fine looking robe,I suppose it could
be used around your azaleas....Considering
the arms move, I wanted the sleeves of this
robe to be Very loose - fitting.
I have no spare "Dead Guy" robes lying
around the house, so I broke out the scissors,
needle, and thread. Other than the fact that
I don't know how to sew, the only problem
I encountered here was the fabric I chose to
use, (it's semi - stiff, as if it was starched)
This problem was solved by washing it.
(easiest "fix" to date...) This is not a nice
fabric to work with. It's rough textured,
and tends to cling to itself somewhat,
however, it's already black,it costs 6
cents/square foot, and it looks like "Dead
Guy" attire.
Here he is with the rest of his robe.I pretty much cut out a huge bib.
I cut a slit to wrap around his "neck" and let the pieces drape over his shoulders and down his back.I cut two more slits for the arms.
This material, being four feet wide, wrapped completely around the torso (loose at the "feet").
I added the forth piece around the head... looks like a hood.
image029This is the prop fully dressed, and fully
extended.He is starting to look  like a
prop. (finally)In my next update I'll include
pictures of the hand making process.
I know hands are available for purchase, 
but they're easy to make, and you can
make them in ANY shape, size, etc.

Pop Up Part 3

I have been making the hands for my new Pop up prop.I am using a combination of techniques I "borrowed" (stole) from some great sites on the Internet.
The basic frame for my hands is made of coat hangers.
image034I also need to make forearms because
my prop's forearms will be visible when
the arms are extended. I used a "cylinder"
of chicken wire to build the base for my
At left is a close up of the method I used
to attach the coat hanger  "fingers" to the
chicken wire "forearm".
I tied each finger in two places with light
gauge wire.
This made the whole arm strong. It's easy
to bend each finger into the desired position.
I lined the forearm (inside and out) with duct tape. I also used this for the palm of the hand. This will give me somewhere to attach the "skin"image036
image037The photo at left shows the manner in
which a cotton ball is "opened up" for
use in the "skin" making process that
follows. First the cotton ball is unrolled, 
then it is gently pulled. I stole this idea
from Britt Griffith via the Monster List
(decayed arm how-to ) Cotton makes a
great "decayed skin" texture.
I first apply cotton to the fingers. At this point, the fingers are only bare pieces of wire. I pull a cotton ball from the tip of the finger to the base, then wrap the finger with thread.This will form the basic shape of the finger.image039
image042I also begin building up the palm area.
Here I simply use a hot glue gun to attach
whole cotton balls.
In the photo you see the "knuckles" being formed, as well as "tendons" on the back of the hand.At this point, the hand should be formed into the desired position, and cotton should be added where necessary to fill everything in.image044
image045In the photo you see the same hand
with one coat of latex applied. I use
Monster Makers mask latex, because
that's what I have. Last year I built hands
similar to this, but coated the cotton with
white glue. That process worked fine, but
latex dries a little faster, and remains
flexible. Latex also builds faster, requiring
fewer coats.
This photo shows the second layer of cotton applied to the hand and arm, followed by a second coat of latex applied with a brush. As the latex dries, it turns a darker shade of yellow. This prop hand is starting to look pretty good.image047
Add layers if needed, just be patient while the latex dries between layers.(I’ve heard a heat gun will speed the drying process.)I recommend buying several inexpensive paintbrushes.I used “acid brushes” because they cost about ten cents.The first time I applied latex with a paintbrush I learned it wouldn’t wash out with soap and water. My favorite camel hairbrush with all of the tooth – marks on the handle was gone for good…Fellow Haunter, Dave (Lothars Lair) sent along some advice:The brush is pre-treated with a soap and water solution.This should keep the liquid latex from adhering to the bristles. Any partially dried latex can be scraped off with a putty knife.
Thanks Dave.

I’d also like to point out that I have about three hours of construction time in this project at this point. (Building two hands) The cost is almost nothing, since I had some latex left over from a previous project. Metal coat hangers are just about everywhere, and no home haunter should ever be without chicken wire, duct tape, or light gauge wire.
image050A few finished (long fingered) hands.They
look creepy enough, but they sure do
take a long time to make.
In light of this, I plan to tackle the molding
and casting arts soon.Is there such a thing
as small scale mass production?

Pop-Up Part 4


At left is a photo of the motion Detecting unit that will be used with the Vile Things Simple Pop- Up.
The PIR sensor head is from a “Regent” outdoor lighting kit.It detects rapid changes in temperature, and activates a relay upon detection.
This model has a 4 second test mode, as well a “1 minute” and “5 minute” run modes.
I opened the sensing head and disconnected the relay from the AC contact voltage.The PIR sensor still requires standard household voltage for operation, but the relay now switches what ever I put into it, which, in this case is 12 volts DC – the output voltage of my homemade event control timer unit.The metal “handi-box” at right will always be “hot.”This will supply power to the PIR motion Sensor head and the timing unit.Upon detection, the timer unit will delay for 10 seconds, then run for ten seconds. The 3 prong receptacle on the timer unit is wired to be “hot” only when the unit is in the”on” mode.By setting the PIR sensor head to the “1 minute” time,I will have approx. 40 seconds of “off time,” during which time the prop cannot be re-triggered.
image053I mounted the PIR sensor head to an
adjustable linkage. This will allow me
to position the viewing lens wherever it
will be the most effective (and least visible.)
He looked kind-of lonely, so I built him a couple of pals. (actuallyit’s part of the set design.)
These guys don’t do anything, they just provide moral support. The building process was identical to that of the 2002 Pop-Up, without any mechanical, pneumatic, or electronic parts.These are very similar to “Monster Mud” props, without the mud.
They each weigh less than twenty pounds.
image058In order to guarantee no haunt visitors
will come close to the Pop-up prop,
I built a section of p.v.c. fence. At a finished
height of 37 inches, it would be difficult to
simply walk over. The bars are spaced 6
inches apart, so even little folks can’t
accidentally walk through.
Here’s a sneak peek at the pop-up room during daylight hours.
image059Before…image061…and after.
image063Night time photos are NOT my thing, but you get the idea.
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