Science Lesson 101
Strictly defined, a vacuum is a space from which most matter, including air and other gas, has been removed. A vacuum exists whenever the pressure within the space is less than the pressure that surrounds it. A vacuum is created when air is removed from within a vacuum chamber. As air is removed, fewer air molecules are present to push on the vacuum chamber walls, so the pressure within the vacuum chamber is reduced. A vacuum cup adheres to a surface due to the weight of the air (atmospheric pressure) pressing against the cup: When air is removed from between the surface and the sealing edge of the cup (the vacuum chamber), the difference in air pressure inside and outside the vacuum chamber causes the cup to adhere tightly to the surface. The weight of air outside the cup is normally 14.7 pounds per square inch, or over 1 ton per square foot, at sea level! If the seal between the cup and the surface is broken, the pressure difference between the two equalizes and the vacuum cup no longer adheres to the surface. When you employ the use of vacuum cups, it is important to remember that certain conditions must exist to obtain optimal performance and hold: The surface that you mount the vacuum cup to should be smooth and nonporous. Rough or porous surfaces allow air to leak into the vacuum area under the cup and will cause a loss of vacuum. Glass, metal and Plexiglas® all offer suitable mounting surfaces for vacuum cups. The condition of the surface that you mount the cups to is also an important factor to consider. Vacuum cups can slip on wet surfaces, and any dirt, dust or debris on the attaching surface or the vacuum cup can cause the cup to lose vacuum and release prematurely.Science Lesson Over
Now that you have a basic understanding of vacuum, you may be asking yourself, "What does this have to do with film making, or budget, or anything for that matter?" Quite simply, filmmakers around the world use vacuum cups from Wood's Powr-Grip to attach all sorts of equipment, including cameras of all shapes and sizes, studio lights, reflective screens, lipstick cams, camcorders, umbrellas and digital cameras. For large and heavy film equipment, like professional cameras, more robust vacuum cups or multiple vacuum cups will be required. The N600NBP is a 10" [25 cm] mounting cup from Wood's Powr-Grip with a special mounting plate for supporting cameras or equipment weighing up to 175 lbs [79 kg]. For applications such as filming a driver through the windshield or from the inside of a moving vehicle, the Wood's Powr-Grip mid-size cups offer adjustable support, camera safety, and a nice steady shot. For smaller items or multiple attaching points, LJ45 or TL6 vacuum cups equipped with ¼-20 threaded posts, adjustable support rods or clamping systems can be used to support any type of film making equipment or prop.What to Look For
While evaluating vacuum mounting cups and accessories, common sense is a filmmaker's best friend. They should make sure to obtain high-quality equipment that will perform the job without exposing their expensive equipment to unnecessary abuse or damage. OEM manufacturers and industry suppliers integrate these vacuum cups with other components to create dependable and reliable mounting solutions. The ability to monitor and sustain the vacuum holding the cup in place is crucial in order to protect a filmmaker's valuable equipment. High-quality vacuum cups, such as those manufactured by Wood's Powr-Grip, are the foundation of many vacuum equipment mounting products. Powr-Grip vacuum cups come with a red-line indicator that warns of any vacuum loss and a check valve that allows re-pumping without the loss of remaining vacuum.Don't Live Life in a Vacuum
As with any professional gear, there are certain things the user must be aware of when employing vacuum mounting equipment. The following is not a comprehensive list, but it will give you some idea of the most common things filmmakers should know. They should always know their gear, and follow the manufacturer's guidelines carefully.- Vacuum cups will only work effectively on smooth, nonporous surfaces.
- Users should always be certain that the surface they are mounting the vacuum cup to is clean and dry.
- Users should examine the surface of all vacuum pads to ensure that they are free of dirt, dust and debris and verify that the rubber pads are not slit or otherwise damaged.
- After placing a vacuum cup on a mounting surface, users pump the plunger down until the red-line vacuum indicator is not visible. Then they must monitor the cup for the reappearance of the red line. If the red line appears, they can pump the plunger again until the red line is not visible. If the problem persists, they should find out why.
- Users should not exceed the manufacturer's suggested weight capabilities of the equipment.
- Users should always be certain that the surface they are mounting the vacuum cup to is clean and dry.
- Users should always tether their equipment. In the unlikely event of vacuum failure, their expensive equipment isn't going to bounce off the pavement.
It's a Wrap
Vacuum mounting equipment is a great tool in the film and video industries--especially when equipped with high-quality vacuum cups from Wood's Powr-Grip. Filmmakers can attach their gear to the mount, pump the plunger a couple of times, and they're ready to go. Vacuum mounts save time, they can be purchased at reasonable prices, and they help to expand film making abilities and indulge creativity. To get the most unique shots possible, filmmakers should look into the void and explore the possibilities with vacuum mounting equipment. You will find vacuum cups and vacuum mounts available through the Wood's Powr-Grip Dealer or Distributor nearest you.David Peters had more than 30 years experience in sales and marketing. He was the marketing associate for Wood's Powr-Grip Co., Inc., responsible for interactive marketing, tracking, market research and new product introduction.