Vacuum Bondage - construction and safe operation

Introduction

This page contains information on the construction (or purchase) and safe operation of vacuum bondage apparatus for use by people with fetishes for bondage, imobilization, mumification, second skin sensation/appearance, or sensory deprivation.

Nomenclature

The technique described on this page is referred to as "vacuum bondage". The apparatus is called a Vac-Rac. Other names include "vacuum bondage table", "vacuum bondage bed","vac rac", "vac-rack", "vac rack", "vacbed", "vac-bed", "vacuum Rack", "vacsack", "deflateable", "deflateable bed", "suction bed", "vacuum packed".

Sensation

The sensation is a combination of complete immobilization, second skin, pressure, and visual sensory deprivation (if a non-transparent bag is used). There may be a breeze, if the bag is not completely airtight, as air leaks in and is evacuated. If the surface you are on is soft (our first tests were on top of a water bed), you will feel your self sucked down into it; if the surface is not soft, you may wish it was. You feel very heavy like on one of those amusement park centrifuge rides. Oddly, one site descibed a feeling of weightlessness - perhaps they were refering to a vac-rac suspension which would distribute the force opposing gravity over the whole body instead of compressing the spine and legs. Some people use a body bag which may have its own fetish appeal to some.

For the observer, the effect is similar to Han's solo being encased in carbonite in Star Wars Episode V: The Empire Strikes Back. Except it looks sexier. It is also similar to looking at someone in tight latex fetish wear. The bag itself may be clear, translucent, or opaque in fetishy colors such as black or red. It also looks like what you would get if you put a human being into one of the blowmold apparatuses used to form plastic (without the ensuing fatality). It also resembles vacuum packed food. The materials used usually have a shiny surface so you get that glossy look so popular in fetish wear.

Apparatus - intro

The apparatus typically consists of a bag made out of plastic or latex, a manifold made out of PVC pipe, and a vacuum cleaner. Some form of breathing apparatus is needed such as a piece of tubing inserted through a small grommeted hole. a hole for the neck (so the entire head is on the outside), a mouth sized hole, some sort of mask, or a latex hood with breathing tube.

Suspension

Vacuum packed people make really neat wall hangings. You can understand why Jabba-the-hut was not happy to give up his favorite decoration, Hans Solo in Carbonite.

Safety

Communication

Prearranged safety signals are essential. The top will probably not be able to see or hear signs of distress between the often opaque material and the noise of the shop-vac. Because of this, if any significant time has passed without an ok signal, the vacuum should be shut down.

Principle Hazzards

  • Asphixiation due to breathing tube malfunction
  • Asphixiation due to chest constriction
    The pressure on the chest can prevent the normal chest expansion which is part of breathing, particularly for smaller people and higher vacuums.
  • freak outs
    If a freak out interferes with breathing, the consequences can be more than just psychological.
  • Loss of circulation due to constriction.
    This is much more likely if limbs are crossed or resting on the torso if there is anything such as rope or leather harnesses which will create pressure points.
  • Bed sores
  • Damage to ear drum due to pressure differential

    In our limited experience, we have not experienced any ear discomfort, let alone damage. However it is theoretically possible to rupture an ear drum, particularly one which has already been damaged. The vac-rac creates the unusual condition where the ear and the airway are at different pressures; if that pressure differential is too great, the ear drum can rupture. Normally, the eustatian tube, which opens when you swallow, maintains the average pressure on the inside of the ear drum at the same pressure as the your nose although if it is clogged due to a cold and you change altitudes you can experience serious discomfort. In the vac-rac, the ear is typically exposed to a partial vacuum while the mouth is exposed to atmospheric pressure; the nose may be at vacuum or atmospheric pressure and may be sealed; in this case, the eustation tube does not help. Lowering pressure slowly while watching for distress signals can reduce the chances of harm.

    Some vac-rac enthusiests believe a latex hood will protect the ears; I am a bit skeptical.

  • too hot/too cold. Like mumification, the person may overheat. That is what ice cubes are for. If the bag is very leaky, then then there will be some cooling from that which will help prevent overheating; in rare cases, there might be too much cooling.
  • Foot over extension. The feet should be laid flat on their sides or vertical. If you start with the foot in tip-toe position (i.e. fully extended), when the vacuum turns on it may get over extended.
  • For any other position other than flat on the back, consider the possibilities of cutting off circulation, over extension of joints, etc. and proceed more gradually. When trying a new possition, it is best to apply vacuum slowly, release after a few seconds, and establish verbal contact; repeat, gradually lengthening the time.
  • It is considerably more difficult to arrange for unobstructed breathing in the face down position (although it does provide a neat view of the posterior). One approach is to use the neck hole method.
  • In vertical suspension, if the vacuum is lost due to a rupture, power failure, or because someone tripped over a hose, you can have an unpleasant fall on your hands. The person is likely to crumple to the bottom of the bag which may rupture under the concentrated pressure. The person will at least sink downward in the bag and will probably lose the breathing tube in the process; they will have some air because the bag has partially inflated at this point but the air exchange will get stale very quickly as there will be negligable air exchange to the outside. If the head is placed through a neck hole, there may be a choking hazzard.
  • People who are extra large or extra small may feel more effect than people who are extra medium (depending on the exact proportions of your apparatus); when vac-racking people who differ in size substantially from those you have done before, be prepared for surprises.
  • Other hazards

    Physics

    Normal atmospheric pressure is roughly 14 PSI (Pounds per square inch). Over the top surface of a typical vac rac, air pressure applies a downward force of about 6000 pounds. Of this, maybe 2000 lbs (depending on the size of the person) presses down on the person in the vac rac (with the vacuum off); this is no different than when you lay in your bed. When the vacuum is applied, the force of air pressure directly on your chest doesn't change; you haven't been depressurized. What changes is that the remaining 4000lbs of air pressing down on the plastic/rubber sheet beside you to you are no longer pressing being met by 4000lbs of air pressure pushing up. There is now only roughly 3300 pounds of pressure pushing up. Taking the difference between those two values, you get about 700lbs of force downward on the plastic beside you which causes it to stretch tightly around you. If the bag was no wider than you, you would feel no significant force when it was deflated any more than you feel the force of air pressure when wearing latex fetish wear (you do feel the stretch of the latex, though).

    These numbers were calculated based on the level of vacuum measured with a small shop vac. If you used an industrial/scientific vacuum pump with a reasonably airtight bag, forces could get significantly higher - with higher risks, accordingly.

    Because the pressure is on the plastic and not directly on the person, extra small people may have more trouble breathing because there is more plastic around them vs over them. If there is too much slack in the plastic before deflation, the bag will deflate almost completely and there will be less downward pressure on you (because much of the downward force will be countered by the upward force on the bottom sheet. If there is enough tension that the top of the bag forms an arc between the vacuum manifold and your body with out bottoming out against the bottom. Extra Large people may tension the covering plastic if it wasn't tensioned before. If the manifold is made of 3" PVC vs. 1/2" PVC, it will be that much taller and the bag will be tensioned under a wider variety of people sizes. If they are so large that they fill up most of the space in the vac-rac, however, the pressure will be reduced accordingly. Thus, the size of the person relative to the overall size of the apparatus and relative to the width of the top sheet can make a considerable difference in how much force one person feels vs. another. Either extra small or extra large (but probably not both for a given equipment configuration) may experience excessive force. Ideally, the apparatus should be constructed so you can adjust the amount of tension in the top sheet before the vacuum is applied. If you need to reduce the force, that can also be done by reducing the vacuum.

    Noise Reduction Strategies

    The noise from the operating vacuum cleaner is a significant problem. It can annoy the vac-rac bottom, the vac-rac top, and spectators; but worse, it can disturb people in other scenes at play parties (particularly when it is first switched on). The last thing someone wants to be reminded of when they are going into subspace is that the need to vacuum the carpets. The noise is largely white noise, however, that once you get used to can mask other noises if it isn't too loud and you aren't turning the thing on and off or constantly changing the speed. There are a number of strategies to reduce the noise.

    The first is to make the system so airtight that you do not need to run the vacuum cleaner at all to maintain the vacuum (one vendor claims they can leave the vac off for something like 30 min); this run the vacuum is very neat but it can be pretty expensive and you still have the noise of the vacuum during pump down (although it may be a smaller vac) and you may not have enough cooling if there is no airflow. Ideally, you would have a leakproof bag and would deliberately introduce the desired amount of leakage, if any.

    A very closely related strategy is to reduce leaks so you can use a quieter less powerfull vacuum or reduce the speed of the vacuum cleaner using a variac ($100? from electronic laboratory equipment suppliers). An SCR based light dimmer such as you might find at a hardware store will also reduce the speed but the motor will run in fits and starts at slow speeds which will not acheive the desired effect.

    Another strategy is to relocate the vacuum outside the play space. This can require long hoses/pipes or partially open doors or windows and if you put it outside, it needs to be sheltered from rain, not disturb the neigbors, etc. On the plus side, the noise of the vacuum outside can help mask the sounds of the play party inside.

    Another strategy is muffling. The vacuum cleaner is placed inside a box that is sealed except for a hole for the exhaust (about 3" diameter will do). The box might be the cardboard box the vacuum came in or it might be plywood. The box may be lined with foam to further reduce noise (but beware, it is flammable and also traps heat). The box may have a series of baffles which are designed to muffle the noise without restricting the airflow. The box may also have a small cooling fan for the vacuum motor if overheating is a problem.

    Grin and bear it. The bottom wears ear plugs. You don't use the vac-rac when/where it could disturb other scenes.

    Apparatus - details

    Size

    Your choice of size may vary depending on your constraints. You may, for example, want it to fit on an existing twin bed with headboard and footboard; this doesn't leave much room for tall people, though. In general the size will probably be somewhere between a cramped 2'x6' to a roomy 4'x8'.

    The manifold

    The manifold distributes the vacuum around so you pump out the whole bag uniformly. If you just stuck the vacuum hose in a corner of the bag, it might just flatten the bag there to the point that air can't escape from the rest of the bag. Or, if the bag leaks a bit, there could be significant pressure differentials in different parts of the bag.

    In industrial holddown operations, the top surface is usually a sandwhich with an airgap in the middle that serves as a duct; holes are drilled in the top cover to spread the vacuum out evenly over the surface. It is sort of the opposite of an air hockey table, but usually much stronger. At least one expensive bondage table uses this type of manifold, which can cost hundreds or thousands of dollars.

    The vast majority of vac-racs use a much simpler system for the manifold. They use $5 - $30 worth (depending on size) of cheap PVC pipe from the hardware store. Somewhere betwen 1/2" and 3" pipe will do. You need two lengths of pipe a bit shorter than your vac-rac is long, two lengths a bit shorter than your vac rac is wide, and one T. You assemble the four lengths and four elbows (corners) into a rectangle. Cut one of the pipes where you want to insert the T which will be the air exhaust (to the vacuum cleaner). Add a short scrap of pipe to the exhaust if desired and add an adaptor to fit your vacuum cleaner hose. If you are making an airtight system, add a valve there too. Now drill a bunch of holes along the inside edge of each of the four pipes. How many holes and how big? The optimum number will depend on many factors of your design and generally isn't critical. A good starting point would be to make the total cross sectional area of your holes equal the lesser of the total cross sectional area of your pipe or the total cross sectional area of your vacuum cleaner hose. So, if the pipe is 1" diameter, you would need 64 holes 1/8 inch in diameter or 16 holes 1/4" in diameter. If your pipe and hose are 3" diameter and you really think you need that much airflow, drill 144 1/4" holes or 36 1/2" holes. If you have too many holes, the vacuum may not be spread out enough. If you have too few, you may not get enough airflow. Also, the plastic/latex bag will tend to cover most of the holes if it is slack. The pipes don't need to be cemented together (so what if they leak a little - you just drilled holes in the pipe); exceptions: if you are doing suspension work, you probably want as much structural integrity as you can get and if you are doing an air tight system you will want cement the joints which are outside the bag.

    For increased effectiveness, rotate the pipes so the holes point downward at a 45 degree angle so they won't be covered as much by the plastic.

    Hull penetrations

    Where the exhaust manifold, signal light wire, pressure gauge hose, intake port, etc. penetrate the plastic is a "hull penetration", a term borrowed from marine use.

    You will probably want to glue scraps of vinyl on the outside to make a stronger and more airtight joint. Cut two large patches of vinyl and coat them with adhesive. Position them on opposite sides of the pipe, hose, wire or fitting and crimp them smoothly together around the pipe and smooth against the bag. A slightly large piece of pipe, cut in half lengthwise, can be clamped around the pipe to help crimp. You can adhere fiberglass mesh tape (used for joining drywall) or strong fabric over the patches for more strength.

    You may want to reduce the number of penetrations by running extra tubes and wires inside the manifold. You will still need to seal the holes but in some situations this may be more convenient.

    You can use duct tape temporarily seal holes, seams, hull penetrations, and tears. If you aren't to picky, you might even use duct tape as a "permanent" solution.

    Exhaust port

    The exhaust port is where the manifold passes through the bag or sheet. The principle concern is how to seal this hole. If you use latex, cutting a hole in the latex that is significantly narrower than the pipe may be sufficient. If you are using disposable 6 mil plastic, you can simply insert a piece of pipe from the outside into the tee on the inside so the plastic is trapped in the joint. If necessary, punch a hole in the plastic using a dowel or steel rod inserted through the pipe. You can also cut a small X in the plastic before you connect the pipe to the T. If you are using heavy vinyl or a body bag, you can use solvent cement to bond the plastic to the tee.

    You may want an adjustable leak where the vacuum cleaner hose joins the manifold. This could be a valve to the outside or as simple as a hole in the side of the pipe which you can choose to cover or not with your hand or a piece of duct tape. This allows you to apply the vacuum more gradually and/or limit the total vacuum.

    intake port

    You may want to install an intake port as well which allows you to create a controlled draft for cooling purposes. A small hose can be inserted through a slit in the plastic and

    The bag or top sheet/bottom sheet.

    The "vacuum pump"

    The "vacuum pump" normally used is just a shop vac or an ordinary household vacuum cleaner. The shop vac is likely to be more powerfull and may be less prone to the motor overheating if there is insufficient leakage. Even a small shop vac will work if the bag is not too leaky. Beware of using an industrial or scientific vacuum pump unless you really know what you are doing as you may get too much downward pressure.

    A speed control is a nice addition. I have seen one shop vac that had a crude speed control built in but it was just an SCR lamp dimmer style that caused the motor speed to sputter erratically at slow speeds as the motor position beat with the AC line waveform. A variac (variable transformer) is a more expensive option that will allow the speed to be varied more smoothly.

    Breathing apparatus

    I use half inch gromets and a roughly 5 inch long piece of clear vinyl tubing which will press fit into the gromet making a tight seal. This is a little on the small side, but workable. You can see the moisture condense and evaporate on the inside of the tubing as the person breathes in and out.

    People use a variety of other forms of breathing apparatus. Some us a piece of latex with an undersize hole cut in it that makes a seal around the neck after the person puts their head through. Some use some sort of mask. Some use a latex hood with a breathing tube. Some masks, snorkles, etc. will crush obstructing the airway, creating pressure points, or otherwise causing injury.

    Signal light

    The signal light provides a way of communicating the person's status to the outside. I used battery powered trunk light from Advance Auto. I removed the switch and installed a female RCA (audio/video) jack in its place. Because of difficulty soldering to the existing battery tabs, I covered them with copper tape and soldered to that as well as tinning over the area of tape which contacted the battery. I soldered a suitably sized and shaped pushbutton switch to another female RCA jack and shrunk a bunch of layers of heat shrink tubing over the pair to hold them together. A 12' long RCA male to male cable can then be run through a slit in the plastic and permanently sealed in. The pushbutton is held in the bottom's hand and the light is placed in a highly visible location outside, prefereably where the top can see the light and the breathing tube simultaneously.

    With extra cables, the same signal light may be used with other bags or in other bondage situations involving gags or other communications imparements. A signal light may even be placed in another room.

    An improvement on this design would be to use a high brightness LED and current limiting resistor in place of the light bulb. Light bulbs can burn out.

    Closure mechanisms

    The primary source of leaks is usually the zipper closure. In fact, a typical zipper leaks so much that we needed to tape over the zipper once it was zipped. Zippers that are both strong and airtight are expensive (hundreds of dollars) specialty items used in dry suits, space suits, etc. A zipper may be any two of strong, airtight, and cheap but not all three at the same time. If it is not under tension, you can use a rail zipper (similar to a ziplock&tm; bag), for an airtight seal. You can use two zippers with an weak airtight zipper attached with some slack over a strong leaky zipper. A quick and dirty, but time consuming, solution is to duct tape over the zipper each time.

    You can make the bag oversize and roll the plastic tightly around a pipe or a piece of flat aluminum (shaped sorta like a yardstick). One self-bondage practitioner actually tucked the excess back inside and rolled it up from the inside.

    There are special two piece plastic moldings at the hardware store that are used to hold clear plastic over windows in the winter. These make a reasonably airtight seal with minor leaks around the corners and other joints. You can clamp two pieces of plastic up to about 15 mil thickness together this way (you might want to roll the plastic into the groove using a spline rolller first).

    You can clamp the two edges together between two pieces of wood or metal with a thick rubber gasket.

    Suspension extras

    Tbd.

    Self-bondage

    I don't recommend vac-rac self-bondage. When, not if, something goes wrong, you are in deep kym-chee. If you must, here are some tips which may reduce the chances of your ending up dead.

    Pictures

    Currently, there are no pictures here. The local BDSM club does not allow consensual photography at group events and my own dungeon is not really suitable for photographing something of this size. so it may take a while. In the meantime, you will find plenty of pictures if you follow the various links below.

    Links

    The many different terms used to describe a vac-rac makes finding information on the internet difficult. One will also encounter many possibly false matches (depending on exactly what one is looking for) to porn sites, fiction, and personal ads. Further, every search engine I tried failed when attempting a complex search that would incorporate the various terms used while avoiding false matches.

    Disclaimer

    Follow these instructions at your own risk. Any use of this information is on an assumed risk basis. Our experience with these devices is limited; we cannot anticipate all the possible complications that could arise even without variations in construction, body physiology/medical condition, application, and just plain lack of common sense. This information is for consensual use only.

    Credits

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