Custom Rubber Pads
Rubber pads are commonly treated as one product, but they serve five mechanically distinct functions with opposite design requirements. A vibration isolation pad must deflect under load to absorb energy; the softer and more compliant, the better the isolation. A structural bearing pad under a bridge beam must resist deflection and distribute load uniformly; a soft pad would compress unevenly and cause the beam to rock. A wear pad in sliding contact must resist abrasion, not compress. Specifying durometer, compound, surface profile, and pad geometry requires knowing which function the pad is performing. Getting it wrong means either poor isolation performance from a pad that is too stiff, or structural instability from a pad that deflects when it should not.
Wayne Rubber manufactures custom molded rubber pads for vibration isolation, structural bearing, wear resistance, equipment leveling, and protective cushioning in Wixom, Michigan. Natural rubber, neoprene, EPDM, urethane, and SBR in flat, ribbed, waffle, and custom profiles. Molded panels and cut-to-size formats.
Rubber Pad Functions: Which Design Problem Are You Solving?
Each pad function requires different durometer, different surface geometry, and sometimes a different compound. The table below is the starting point for any pad specification. Identify the primary function first, then determine the compound based on the environment.
Placed under rotating or vibrating equipment to attenuate transmission of vibration to the supporting structure. Design requirement: compliance. The pad must deflect under the static weight of the equipment to store and release energy, reducing transmitted force. Softer durometers (30-50 Shore A) provide more deflection and therefore better isolation of high-frequency vibration. The pad contact area must be sized so the static pressure stays within the pad’s design load range (typically 20-80 PSI for standard rubber pads). Surface profile: ribbed or waffle patterns increase effective compliance by allowing the rubber between ribs to deflect laterally as well as vertically, improving isolation at lower static loads. Flat pads at equivalent durometer provide less deflection than ribbed pads of the same compound under the same load. Stacking for more isolation: two pads with a steel shim plate between them provide approximately double the static deflection of a single pad, improving isolation of very low frequency vibration that a single pad cannot adequately attenuate.
Load-bearing elastomeric pads used beneath beams, girders, precast concrete panels, bridge decks, and structural steel elements to distribute load uniformly over the supporting surface, accommodate thermal movement, and provide a measure of seismic compliance. Design requirement: controlled stiffness. Unlike isolation pads which should be as compliant as possible, bearing pads are specified for a defined static load capacity at limited deflection (typically less than 15% compression under design load). Natural rubber laminated bridge bearing pads are designed and tested to AASHTO standards with defined shear modulus, compression stiffness, and creep limits. The critical difference from isolation pads: a bearing pad under a structural member must not creep over time. Creep reduces the effective bearing area and can cause uneven load distribution. Reinforced natural rubber or neoprene bearing pads with steel shim laminations resist creep far better than plain rubber pads at equivalent durometer.
Rubber pads bonded or mechanically attached to surfaces experiencing sliding contact, impact from dropped objects, or abrasion from moving material. Design requirement: abrasion resistance. Unlike isolation and bearing pads which work in compression, wear pads work in sliding friction and impact. The compound must resist the specific abrasive contact; dry grain requires different wear resistance than wet sand slurry. Compound selection: natural rubber provides the best abrasion resistance at equivalent hardness for dry material contact; polyurethane exceeds natural rubber in wet abrasion and cut resistance under sharp aggregate; UHMW polyethylene is used where a non-rubber wear surface is acceptable. Hard durometers (60-80 Shore A) resist abrasion better than soft durometers at equivalent compound. Attachment: wear pads must be replaceable, so mechanical attachment (bolted through the pad) is preferred over bonding for surfaces that require periodic pad replacement. Bolt holes must be reinforced at the pad edge to prevent tearing during removal.
Pads placed under equipment to level it on uneven floors, to prevent the equipment from walking or skidding under vibration, or to protect the floor surface from the equipment’s feet. Design requirement: high friction and dimensional stability. The pad must grip the floor and the equipment foot simultaneously without creeping or spreading under the static load. High surface friction (coefficient of friction greater than 0.6) is achieved through surface texture, compound selection (natural rubber provides highest friction against most surfaces), and adequate contact pressure. The anti-skid function works differently from isolation: a stiff pad at adequate contact pressure grips better than a soft pad that spreads under the equipment weight and reduces contact pressure. For anti-skid applications without isolation requirements, 60-70 Shore A neoprene or natural rubber provides better dimensional stability and grip than 40 Shore A isolation compound.
Pads that protect surfaces from impact damage, prevent metal-to-metal contact, cushion cargo or components during transport, or provide a compliant interface between two rigid surfaces in assembly. Design requirement: energy absorption. The pad must absorb the kinetic energy of impact without transmitting damaging force to the protected surface. Higher hysteresis (energy loss per compression cycle) absorbs more energy but produces more heat in repeated impact applications. Neoprene and SBR have higher hysteresis than natural rubber and are better at absorbing repeated impacts. Natural rubber returns more energy per cycle (lower hysteresis) and is better for applications where the pad must spring back quickly between impacts; dock bumpers on high-cycle vehicle docking applications. Thickness: thicker pads absorb more energy per impact at equivalent durometer, simply by having more material to compress before the force is transmitted to the backing surface.
Pad Surface Geometry and What It Does
Maximum contact area with both the equipment base and the floor surface. Highest friction coefficient. Best for leveling, anti-skid, and protective cushioning. For isolation, flat pads require softer durometer than ribbed pads to achieve equivalent deflection under the same load. Also used for bearing pads where uniform load distribution across the full pad area is required. Thickness variation across the pad is determined by the molding process tolerance.
Parallel raised ribs on one or both faces with recessed channels between them. Ribs allow lateral expansion of rubber between ribs under vertical load, increasing deflection at equivalent durometer compared to flat pads. Standard for equipment isolation under motors, compressors, HVAC units, and generators. Drainage channels between ribs prevent water pooling under equipment on wet or washdown floors. Rib geometry (height, width, spacing) is adjusted to tune the load-deflection curve for a specific equipment weight.
Grid of raised pads or recessed squares on both faces, creating a waffle-iron pattern. Provides compliance in two lateral directions simultaneously, improving isolation of equipment with vibration in multiple axes. Can be cut to size in the field at the waffle grid lines without requiring a saw or specialized tool. Widely used for HVAC rooftop equipment, generators, and industrial compressors where field-adjustable size is needed. Lower load capacity per square inch than ribbed profiles at equivalent durometer because of the reduced contact area.
Diamond, herringbone, studded, or custom surface texture molded into the pad face to maximize friction coefficient against a specific mating surface. Used for anti-skid leveling pads, floor safety mats, and protective cushioning pads where the pad must not slide relative to either the floor or the equipment. Surface texture can be molded into one face (equipment contact) with a smooth face on the floor contact side, or textured both faces depending on the grip requirement on each interface.
Wayne Rubber produces custom pad profiles to customer drawings: stepped pads for equipment feet of defined dimensions; pads with molded-in bolt holes or retention features; pads with bonded metal inserts for defined load distribution; asymmetric profiles for equipment on sloped floors requiring a wedge-shaped pad to level; and pads with perimeter retention lips that prevent lateral drift. Custom profiles require tooling but allow the pad to be engineered specifically for the equipment and installation, rather than adapting a catalog pad to an application it was not designed for.
Alternating layers of rubber and steel plate bonded together in a sandwich construction. The steel layers prevent lateral bulging of the rubber under vertical load, increasing the pad’s vertical stiffness relative to its shear stiffness, the essential characteristic of structural bridge bearing pads. Laminated bearing pads to AASHTO standards are available from Wayne Rubber for bridge and structural applications. The steel laminates also virtually eliminate creep under sustained load, unlike plain rubber bearing pads which creep progressively over years of sustained compressive stress.
Rubber Pad Compound Selection by Application
| Compound | Pad Applications | Key Properties | Avoid When |
|---|---|---|---|
| Natural Rubber | High-performance vibration isolation pads for precision machinery; structural laminated bridge bearing pads; dock bumpers with rapid rebound requirement; wear pads in dry abrasion service; anti-skid leveling pads requiring maximum friction | Highest resilience (lowest energy loss) for efficient vibration isolation; best dry abrasion resistance at equivalent durometer; highest surface friction coefficient; standard material for AASHTO bridge bearing pads; lowest hysteresis for rapid rebound dock bumpers | Petroleum oil or fuel contact; outdoor UV and ozone exposure without protective coating; any chemical environment; sustained outdoor service where EPDM or neoprene outlasts natural rubber significantly |
| Neoprene | General-purpose isolation pads in moderate oil-splash environments; outdoor generator and HVAC isolation pads with UV exposure; dock bumpers and equipment cushioning pads in shop environments; leveling pads in manufacturing facilities with occasional oil contact | Balanced oil, UV, and ozone resistance for general industrial pad applications; moderate hysteresis for energy absorption in cushioning applications; good compression set resistance for bearing pads under sustained load; the most common general-purpose pad compound for industrial environments | Sustained petroleum oil or fuel immersion (NBR better); best-possible vibration isolation where natural rubber’s lower hysteresis provides better performance; sustained outdoor UV service over 10 years (EPDM outlasts neoprene) |
| EPDM | Outdoor equipment isolation pads with sustained UV exposure; rooftop HVAC unit pads; electrical substation equipment pads; water system pump isolation pads; tank and vessel bearing pads in water service; outdoor generator isolation | Best UV and ozone resistance of any standard pad compound; long outdoor service life for rooftop and substation equipment pads; good water resistance; lower cost than neoprene for outdoor-only applications | Petroleum oil or fuel contact; high-friction anti-skid requirement (lower friction coefficient than natural rubber and neoprene); wear pad applications in oil-wetted environments |
| SBR | General-purpose cushioning pads for protective applications without chemical exposure; low-cost protective floor pads and equipment base pads in clean indoor environments; dock bumpers in light-duty applications; vibration pads for light equipment in clean facilities | Lowest cost rubber pad compound; adequate for light-duty protective cushioning and general equipment base pads in clean indoor environments; good abrasion resistance relative to cost | Any outdoor UV or ozone exposure (cracks rapidly); oil or fuel contact; sustained compressive load in bearing applications; any regulated application requiring a defined compound certification |
| Polyurethane | Heavy-duty wear pads in severe abrasion environments (wet aggregate, mineral slurry, grain conveyors); high-load cushioning pads where rubber would compress excessively; scraper blades and conveyor wear liners in pad form; mining and aggregate chute wear pads in wet service | Highest abrasion resistance of any elastomer for wear pad applications; significantly longer service life than natural rubber in wet abrasive environments; high load capacity at equivalent thickness; use EU grades for wet/water-contact applications | Hot water or steam above 140°F (EU grade limit); vibration isolation (polyurethane’s high modulus provides poor isolation); sustained petroleum solvent contact; applications requiring pad flexibility for installation over irregular surfaces |
Rubber Pad Applications by Industry
- Rooftop air handling unit isolation pads (EPDM ribbed)
- Chiller and cooling tower isolation pads
- Pump and compressor isolation in mechanical rooms
- Fan coil unit vibration pads
- Generator set isolation pads (neoprene or natural rubber)
- Cooling tower basin leveling pads
- Machine tool isolation pads for CNC machining centers
- Press and stamping machine floor isolation pads
- Conveyor drive motor isolation pads
- Industrial compressor and pump isolation
- Precision instrument anti-vibration pads
- Welding and fabrication equipment base pads
- Bridge bearing pads (laminated natural rubber to AASHTO)
- Precast concrete panel bearing pads
- Building expansion joint bearing elements
- Pipe support isolation pads in mechanical rooms
- Temporary construction equipment base pads
- Seismic isolation bearing elements
- Conveyor belt wear pads and skirtboard liners (urethane or NR)
- Crusher and screen isolation pads (heavy-duty natural rubber)
- Chute wear pads in abrasive slurry service (urethane EU grade)
- Vibrating screen deck wear pads
- Drill rig base isolation pads
- Impact zone cushioning pads at conveyor loading points
- Dock bumper pads (high-rebound natural rubber)
- Ship fendering pad components
- Crane rail isolation pads
- Cargo deck cushioning and protection pads
- Container and pallet isolation pads during sea transport
- Pipe support bearing pads on deck and pier structures
- Assembly fixture anti-skid pads for component holding
- Engine and powertrain test stand isolation pads
- Vehicle transport protection pads
- Press bed cushioning pads in stamping operations
- Robot and automation equipment base isolation
- Dyno test cell isolation pads for engine and drivetrain testing
Also from Wayne Rubber
Request Custom Rubber Pads from Wayne Rubber
Provide the pad function (isolation, bearing, wear, leveling, or cushioning), equipment weight and footprint, surface profile requirement, operating environment, and quantity. Wayne Rubber will specify the compound, durometer, profile, and size, and provide a quote with piece cost and any tooling.