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- Pneumatic Release
- By Riddle
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- Originally posted in the forum: http://forum.boundanna.net/board/viewtopic.php?f=7&t=1796
- (Please look there for even more information
and warnings on this subject.)
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- Safety is always paramount in an daily
life. Self bondage requires even more attention to detail to
ensure safety. Some bondage release setups have bothered me in
the past and I am constantly seeking a safer and more secure
method to time the release.
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- This search brought me to this forum and
to study pneumatics. Keys magnetize, temperatures vary, and strings
tangle. Compressed air can provide much more holding power than
an electric magnet, without the concern of electric wires attached
to your bondage setup. Compressed air may provide hundreds of
pounds of pushing or pulling power with a fairly small cylinder.
This force must never push or pull on the restraints or anything
else attached to the body. Safety is my highest priority.
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- By replacing the electric magnet on the
self-bondage stocks with an air cylinder moving a pin, the holding
power can be increased substantially. Then again, I do not want
to spend $100 on a magnet that may not hold well enough. By using
an industrial air cylinder on each wrist cuff, I have increased
the redundancy to double. The 3/4 inch bore X 1 inch stroke air
cylinders at the local industrial supply company cost me about
$15 a piece. The single acting ,spring loaded return ones are
the cheapest and safest in my opinion. These require air pressure
to continue holding and return back when the air pressure is
gone. Double acting cylinders require air pressure to move in
either direction. The most common failure in industrial applications
is air leaks. This will at least reduce the strength or cause
complete lack of function, depending upon the rate of air loss.
Only in extreme cases under severe conditions will a lack of
imaintenance cause the cylinder to seize up. For bondage applications,
careful inspection and lubrication will ensure this will not
happen. Then again, I will not ever see my cylinders reach over
100,000 cycles while exposed to constant industrial dirt and
grime. My home is cleaner than that.
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- I have no intention of building the electric
stocks as shown on the main page. My intended application is
in both a wooden cross format and a medical 6 point bed tie down
setup. My wrist restraints are locking medical restraints which
require the other hand to unlock and release. Due to this limit,
I desire a release mechanism that lets go of the restraint instead
of the key. An electric magnet capable of holding is well beyond
my budget. Then again, a magnet requires a metal plate to hold.
This is often heavy, gets warm, and shall never be above my head.
With the cylinder operating a moving pin to catch the tie down
ring on my wrist restraints, the release should be extremely
reliable and only be holding the weight of my restraints. So
far, this sounds safer to me.
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- By using air pressure to hold, I am hoping
to build a setup with sufficient redundancy to prevent another
scare. With multiple timers controlling multiple electric controlled
air valves, the release should occur at the programmed time.
All air valves will be wired and plumbed to dump the air pressure
when they lose electricity. In the event of a power outage, I
will be instantly released. The electric valves that I chose
have 12 volt coils. This allows me to power the relays from an
exhaustible power source (batteries). The timers will be plugged
into the wall but will only control more relays in line with
the battery power. The air compressor will never be directly
attached to the bondage setup. I desire to use a small portable
air tank to supply the initial pressure, By intentionally installing
a small air leak, the pressure will not last forever as a final
fail safe.
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- Each of the air components were selected
by air pressure rating to ensure safety. My air compressor shuts
off at 100 PSI. Therefore, anything rated above that in industrial
applications is safe. The valves are rated at 125 PSI. The fittings
are 160 PSI. The hose is 250 PSI (this is the most critical in
an air system). The air cylinders are rated at 300 PSI.
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- My parts order was at the store today!
Both air valves and air cylinders are in my possession and tested.
The function is good, but the air cylinders are noisy in operation.
The finished product will be cushioned with rubber grommets to
reduce noise.
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- The following images are the actual parts
that will be used.
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- This is the electric air valves (solenoid
air valves). The pair are bolted together and connected to a
compressed air supply. The upper connection is normally closed
and the lower one is normally open. The brass item installed
in the lower port is an air exhaust muffler.
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- Now comes the fun part, building the brackets
to hold the air cylinder and sliding pin.
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- Here is pictures of the build process
and the completed prototype (prototype as in work in progress).
At this time, I have not connected the air lines or set up the
controls. The plastic lines with duct tape on the ends is there
to keep the air cylinders free from debris during the contruction
and will remain as long as the air lines are not connected. Until
the sawhorse is comfortable and safe, the controls are not needed.
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- Click on the pictures for a larger view.
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- Here is a picture of the rough draft of
the cylinder and 4 inch sliding latch inlaid into a 2x4. In the
background is the other cylinder and latch connected together.
The piece of wood over the cylinder is bolted to the air cylinder
mounting bracket. This was replaced with a 3/16 thick steel plate
in later designs.
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- The latches have notches on one side.
When installed into the 2x4, the latch should never be able to
turn into the notch because of the tight fit of the groove cut
into the board. I used a 3/16 thick piece of steel about 1/2
inch wide by 4 inch long. On the cylinder end, I drilled a hole
the correct size for the pin on clevis (the end of the piston
rod). The other end of the steel was drilled with a 3/16 inch
hole and notched on one side to barely fit over the latch handle
at the skinny portion. The notch in the steel is opposite the
notches in the latch to prevent it from disconnecting or jamming.
The groove in the wood is also a close fit for the steel bar.
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- Notice that the latches will be mounted
upside down in the finished product. This is why I will not use
this design for any bondage that could place my full weight upon
the latch. If the sliding bolt is partially pulled out, it may
jam and fail to release.
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- Here is the next 2x4 already drilled out
to begin carving out the space for the air cylinder and latch.
After this point, all further wood removal was by hand with chisels.
The holes were drilled with spade wood drill bits. This type
of drill bit leaves a fairly smooth and flat bottom except for
the center point but does not work well when re-drilling holes
bigger.
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- Here is the the second draft of the inlaid
parts. After the groove was cleared out, another hole was drilled
from the air cylinder end of the board large enough for the air
cylinder to enter, thus allowing a shorter groove, easy air line
connection, and extra wood above the air cylinder. Minimal wood
was removed to prevent the board from breaking. Most of the air
cylinder is to the right of the piece of wood in this image.
The groove for the steel connecting bar is as long as possible
and a close fit to prevent problems. In this image, you can see
the rubber bumpstops. On the piston rod just to the left of the
piece of wood is a black rubber grommet. This prevents the cylinder
from traveling all of the way back and cushions the stop. At
the far left end of the latch groove is a clear plactic bumper
for the latch bolt to strike. Fully piston travel is unavailable
in this direction also. These cushions quiet operation and extends
cylinder life (the cylinder is not pounding itself to death).
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- Here is the first picture of real progress!
The middle board is the rough draft. Above and below it are 2
finished, functional air controlled bondage latches. The upper
latch has a medical restraint cuff sitting in place ready to
work. As you can see, the groove is covered by a 3/16 steel plate
held in place by 8 countersunk wood screws (gold color). The
2 zinc plated countersunk screws hold the air cylinder in place.
(sorry, my soda reserve also appears in the photo.)
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- Here is what not to do! When using countersunk
wood screws, one must be very careful to prevent splitting the
wood. All screw holes were pre-drilled and countersunk to prevent
wood splitting. One good trigger pull on my corded drill sent
the screw too deep and caused this split. The screws should be
installed either by hand or with a variable clutch drill. Without
the clutch, it is very easy to ruin pieces. I have several split
boards that must be replaced.
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- Here is the arm rests installed on the
wooden saw horse. Notice that they are perpendicular to the legs
instead of parallel to the ground. This is extremely awkward
and uncomfortable. To bad all 4 rests must be completely redone
to fix this error. When the rests are leveled, the split boards
will be replaced.
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- How does this look? Pardon the clutter,
I have limited space and did most of the work in my living room.
The leg restraints are held in place semi-permanently by a piece
of wood going through the d-ring and screwed into the 2x4. No
need to lock these since no one will be reaching them and leaving
early.
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- This project was built using regular 2x4
lumber and basic tools. One power tools was required and two
others were a big help. A 3/8 inch drill with variable trigger
was invaluable for this project. The 7.25 inch circular saw (skill
saw) and electric palm sander were very helpful and saved much
time. The wood used for this project was scraps that I had laying
around. A set of regular drill bits, spade wood bits, wood chisels,
one countersink bit, and some screw drivers complete the tool
listing. The metal plates could be purchased from a metal supply
store already cut to size. With either sand paper or a metal
file, the plates can be smoothed up nicely. The bevel on the
plates was done with a file and some patience. A disc grinder
would make the bevel faster to make, but would still require
a fair amount of smoothing. The steel connecting bars could be
made from 3/16 bar stock 1//2 inch wide. Dimensions may be modified
depending upon local availability. Just don't go too thin.
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- Here is my final update for this thread.
The project works very well. It may even be considered too good
for some SB enthusiasts. Once everything is in set up and the
bondage starts, there is no option for second thoughts. This
setup will hold for the set time: no more, nor any less. This
design has no mercy for those who set the timer too long. You
will be securely bound for the entire session.
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- Before trying any actual bondage with
this setup, I intentionally tried to break the latches with my
dominate hand. By only using one restraint cuff fastened but
not locked, the latch was tested for weakness. I did not have
the strength to pull the latch pin out of its mounting bracket.
It is strong enough to not even allow me to pull the pin up enough
to jam the mechanism. It simply held. If I was using this latch
on a bondage cross or post, my full body weight on a single latch
may be enough to wedge the latch pin into its mounting bracket.
Therefore, this design shall remain solely for installation into
an arm rest for either a bondage chair or sawhorse. By staying
within these boundaries, my self bondage sessions should remain
safe enough for years to come.
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- Here is some pictures of the final design
for your information. Clicking on the picture will bring up a
larger image.
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- Here is the electric relay to control
the wall power with batteries. The grey box is a home electric
outlet box with a blank cover. On the side is a 120 volt coil
relay from Radio Shack installed into a mounting bracket. The
mounting bracket is installed into a carefully cut hole in the
side of the box. All wires are soldered onto the mounting bracket
electric tabs. The relay simply plugs into the mounting bracket
to connect all of the wires. By using this method, the relay
is easily removed or replaced as needed without concerns of disconnecting
any wires. When the coil is energized by the electric timers,
the battery wires are connected to the black wire leaving the
box. With this method, only 12 volts from AA batteries is ever
connected to the actual bondage furniture.
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- Here is a picture of my timers connected
to an power strip. Yes, there is 3 digital timers used. You cannot
be too careful with bondage. The first timer (closest to the
power strip) has its outlet opposite the input. It is a weekly
timer with up to 20 separate on/off times. I only have one off
time set into this timer for every day of the week. This way,
it will always turn off today. The other 2 timers are only daily
timers with up to 6 on/off times. They are supposed to have watch
batteries installed to keep the time and timer routine stored.
The batteries are normally removed. This way, once they lose
their power input, they will never turn on without my intervention.
The default mode for these timers is off.
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- The timing setup for the bondage setup
is simple. The first timer is set to turn off a while after the
desired end time (30 minutes or so). After setting its off time,
I manually turn on its output to set the next timer. The second
timer is set either close to or right at the desired end time.
Once it is set, I turn on its output and set the final timer.
The final timer is set with both an on and off time. The on time
gives me time to get into position before the latches slam shut.
The off time is set for the desired release time. This allows
for a very precise bondage time.
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- Here is another electrical box installed
at the end of the lower center 2x4. This contains a switch, circuit
breaker, and electrical connection strip. By having a switch
on the bondage furniture, I can cycle the valves multiple times
to verify proper operation of the air valves, cylinders, and
latches quick and easy. Due to its mounting location, I cannot
operate the switch while in bondage. The wiring setup requires
the switch to be in the “on” position before bondage
can start. If I need to perform a last minute abort before both
hands are held down, I have that option.
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- Here is a picture from the foot end of
the sawhorse. From this fuzzy (sorry about the quality) image,
you can see the air valves bolted into place, the air lines going
from the valves to the input connector, and the wires from the
valves to the connection box. The wires were wrapped with plastic
spiral wrap to prevent them from damage and held in place with
plastic cable clamps. The brass item above the grey box is the
compressed air input connection. I used industrial quick connections
on the supply line, air tank, and air hose. For a slow air leak,
the brass fitting is not tightened all of the way. The air leak
is extremely slow, but will eventually allow me to be released
if all else fails. The fitting is screwed in enough to prevent
it from unscrewing. The sawhorse leg protects me from this leaking
connection both from the possible chill of the air leak, and
from the hose if it came loose. The air lines on this side are
also held in place with cable clamps.
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- Here is a better view of the air lines
and valves. Notice that the air valve inputs and outputs are
connected to a common line. This means that both valves use the
same air supply and must work together to hold me bound. If the
valves are ever in different positions, the supply line gets
connected to an exhaust port and is quickly dumped. This ensures
that if one of the valves fails to function, I will be released.
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- Here is another picture of the air lines.
In this photo, you can see how the air lines are connected to
the arm rests. Notice the short lines. If one of these comes
loose, I should not get hit with the air line. The air released
may chill me some, but there is not enough compressed air to
cause frostbite. The air cylinders only require 0.88 cubic inches
of compressed air for full movement. Therefore, very little air
comes out of the exhaust ports under normal conditions. I put
my hand on the mufflers and cycled the valves a few time to feel
the output. The output was barely noticeable at that distance.
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- This picture is the new top board on the
sawhorse with a variety of metal rings beside my locking wrist
cuffs. All of these hardware items except for the green clips
fit into the latches. With this design, you could use the latch
on rope, chain, wrist cuffs, or anything else that could be attached
to one of those hardware items. You are not required to go out
and purchase an expensive set of wrist cuffs. The latch could
easily be used to replace the electric magnet in the SB wrist
stocks described elsewhere on this website.
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- In this image, you can see the arm rest
with a metal chain link resting in the cutout slot without the
latch activated.
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- In this image, you can see the arm rest
with a metal chain link resting in the cutout slot with the latch
activated. Notice the pin goes all the way to the plastic bumpstop.
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- This image shows the tank connected to
the sawhorse. The yellow coils is the air line. Between the air
line and tank is a pressure regulator and air filter. It connects
to both the tank and air line with quick release couplers of
the same type as used elsewhere. The pressure regulator is set
at 60 PSI, a reasonable pressure. This is set just high enough
to allow the valves and cylinders to function quickly, but not
so much that the cylinders have full force. At this pressure,
the entire sawhorse shakes when the pistons move. Anything more
is overkill. The tank has 2 couplers and a pressure regulator
permanently mounted to the tank for other purposes unrelated
to bondage.
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- Here is both of my portable air tanks
with the focus on the larger one. The red tank is 11 gallons
(more than I want/need for bondage) with just a quick coupler
installed into its tank valve. This would be the preferred setup
to connect the regulator and filter to the tank. The black seven
gallon tank is from the automotive section at Wal-Mart. These
tanks were originally intended to quickly inflate car tires.
By replacing the original air hose (which had a permanent tire
chuck on one end) with a compressed air fitting, I am able to
use them for other purposes. The intended method to fill these
tanks is with an air chuck on the valve. You could use the same
air source that you use for your car to fill these tanks. A good
air compressor would be the best method. The cheap 12 volt tire
inflation pumps would burn up before inflating one of these tanks.
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- After completing the setup and testing
it a few times, I have decided that it works very well. This
provides strict bondage for the desired time. Due to the unforgiving
nature of this bondage setup, I plan to add additional safeguards
to the electric controls in the future. In case of emergency,
there is no release. I currently have a mechanical thermostat
with plans to purchase another. One will be set to either 85
or 90 degrees Fahrenheit. The other will be set to 65-70 degrees.
The upper one will release if something causes the temperature
in my home to go higher than desired, such as a fire. The lower
one will be protection from low temperatures. The only change
to the air system that I would like to make in the future is
the tank itself. At 1 cubic inch per cycle of the air valves,
I have not been able to come anywhere near using the seven gallons
available. A much smaller tank permanently mounted to the sawhorse
would be more appropriate. I will probably try either 1 ¼
or 2 inch PVC pipe with one end capped and the other connected
to the air valves through a ball valve. A 1¼ inch piece
of pipe 12 inches long has 14 cubic inches of air volume. This
would be plenty for one bondage session. For those without a
compressed air source, a cheap bicycle pump capable of 60-70
PSI would work just fine with such a small tank. Even one of
the $10 12 volt car tire pumps could handle this as long as the
user did not over-inflate the tank.
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- As previously mentioned, this setup allows
for strict bondage. The first session with it was rather uncomfortable.
I set the timers for about 45 minutes and had plenty of time
to rethink the design of the sawhorse. For padding, I laid a
pillow on top of the sawhorse for my chest and face. For the
lower torso, several layers of cloth provided the padding. On
my knees, I wore a pair of cheap foam knee pads. After the timer
latched the wrist restraints, I was stuck. After a few minutes,
I realized that no matter how smooth a 2x4 is sanded, one cannot
comfortably lay down on one. The next thing that I noticed was
the leg and arm rests were too high. To actually lay on the top
board, I had to either slide forward or back. This put either
my arms or legs at an awkward angle. The next thing discovered
was the added pressure on the stomach and bladder. If the stomach
is irritated at the start, it will become upset shortly. The
bladder should be empty before starting. Nether of these actually
caused any issues, but are mentioned so that you are aware. The
wrists and ankles could not move the entire time. Any discomfort
with the position had to be ignored because there was nothing
that I could do about it. My right knee tends to be a little
sensitive to constant pressure at this time. During the session,
it let me know more knee padding was required. At the end of
the session, I was very happy for release.
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- I made changes to the sawhorse to make
it more comfortable before trying again. The biggest change was
installing a 2x8 on top of the top 2x4. This not only widened
the resting place, but also had the effect of lowering the arm
and leg rests. The foam knee pads were replaced with fabric lined
knee pads with a hard plastic cup on the bottom. These relieved
most of the pressure on my knees by spreading out the pressure.
After an initial test fit without the restraints in place, I
set the timers for 2 hours and tried again. An hour would have
been a better choice. This time, everything went much better,
but I did find some room for improvement. The knee pads did not
stay in place on the rests because of the plastic bottom. A set
of knee pads with the rubber grip surface would have been a better
choice, but I did not get them because of the added cost ($25
instead of $10). The thickness of the new knee pads meant that
the ankle restraints needed to be raised up to give a more comfortable
level position. After a while, I noticed that the insides of
my legs were getting sore because of the edge of the top board.
I curved the upper edge to roughly a quarter inch radius. Half
or one inch would have been much better. The distance between
the leg and arm restraints needs to be another inch or 2 for
more comfort. Other than these minor irritations, this session
went very well. In the future, I may set the timer for longer
periods of time after improving the comfort some more. Either
that, or make a bondage chair.
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- At this time, only one question remains.
Would you try this?
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- Originally posted in the forum: http://forum.boundanna.net/board/viewtopic.php?f=7&t=1796
- (Please look there for even more information
and warnings on this subject.)
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