Do I need vacuum pads with a special kind of rubber?
by Jessica Smith

The use of a vacuum cup may seem simple and straightforward to an unfamiliar observer; in fact, some people are amazed simply by seeing the power of vacuum used to lift, position or mount a load! One of many factors that need to be considered when choosing a vacuum cup or below-the-hook lifter is whether a special rubber is required for a vacuum pad in that application. Some of the factors that influence this choice include: how well the pad performs on cold or hot surfaces; whether the pad itself leaves marks or residue on the material; how long the pad will be attached; and whether or not the security of the load is compromised by water, solvents, oils or other contaminates on the surface of the material. The correct choice of rubber material improves the performance, safety and cost effectiveness of the vacuum lifting device for these special applications. This article introduces the various types of rubber compounds Wood’s Powr-Grip commonly uses and discusses the applications where special rubber types may be required.

General Purpose Applications

Vacuum pads are not always made from a single material. Combinations of ingredients are formulated to change various characteristics of the compound to address specific handling requirements. These components include natural and synthetic rubbers, colorants, fillers and polymers, which result in unique pad characteristics. In our most widely used rubber compound, Wood’s Powr-Grip uses a special blend of natural and synthetic rubbers designed specifically to meet a wide range of applications. Excellent for use in climates from 10° to 120° F (-12° to 49° C) and in applications where cups are attached for periods of less than two hours, this compound provides excellent adhesion, abrasion resistance and rebound (an ability to return to its original shape). This blend also increases pad life by resisting aging caused by U.V. (sunlight), ozone, oxidation and heat. And because this rubber compound is relatively inexpensive, easy to mold and store, general purpose pads are readily available at an affordable price.

Low-Marking and Extended Adhesion Applications

Various ingredients used to improve the characteristics of general use pads can leave behind trace residue on the load surface. Comprised almost wholly of NATURAL RUBBER and a gray colorant, Wood’s Powr-Grip’s low-marking pads are used in applications where workers are handling nearly pristine surfaces. Natural rubber has excellent adhesion, abrasion resistance and rebound qualities, even in extremely cold temperatures. Unfortunately, natural rubber does not fare well when exposed to U.V. or ozone for extended periods of time.

EPDM rubber (ethylene propylene diene monomer) is a good general purpose rubber often used for outdoor applications due to its excellent resistance to U.V., ozone, oxidants, heat and abrasion. Most often specified for use in or on vehicles, EPDM is the standard compound used for Powr-Grip vacuum mounting cups. EPDM has good rebound in both cold and hot environments and is especially well suited to severe weather conditions.