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Gaskets and Non-Marring Contact Pads
Urethane Gaskets and Non-Marring Contact Pads
Urethane’s combination of toughness, elasticity, and low-friction surface makes it an outstanding gasket material for sealing and cushioning applications. Polyurethane gaskets and pads provide high load-bearing capacity and abrasion resistance, while also offering non-marring (non-marking) contact surfaces that protect delicate components. In practice, these parts serve as seals and spacers for fluid or air isolation, bumpers and pads for shock/vibration damping, and non-marring contact surfaces in packaging, automation, and glass/metal handling. Urethane pads absorb impact and reduce vibration, preventing damage to products or equipment. Thanks to chemical and abrasion resistance, urethane sealing strips and gaskets outlast rubber or metal in harsh environments, giving manufacturers a longer service life and lower maintenance.
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Each application takes advantage of polyurethane’s unique benefits, exceptional abrasion/cut resistance, and very high rebound, as well as its non-marking surface properties.
- Sealing & Isolation: Soft urethane sheet or strips compress to form tight seals against oil, chemicals, or air leakage.
- Impact Pads & Bumpers: Energy-absorbing pads cushion impact in automation or material handling.
- Non-Marring Contact Surfaces: Medium durometer pads contact glass, painted metal, or delicate goods without scratching.
- Heavy-Duty Spacers: Firm spacers under heavy equipment reduce noise and isolate vibration.
Recommended Durometer (Hardness)
Choosing the right hardness (durometer) is critical. Polyurethane covers a very wide hardness range (20A to 90A Shore A for most applications), with soft grades being very elastic and hard grades being stiff and wear-resistant. In general:
- 50A–70A (Flexible Sealing): Soft-to-medium urethanes (~40–60A) provide excellent elasticity and compression. These grades are ideal for gaskets and sealing layers that require flexibility under compression. (For example, a 40A sheet yields a very rubbery cushion perfect for compression seals.)
- 70A–85A (Non-Marring Contact Pads): Medium-hard urethanes (~70–85A) balance durability and softness. They are commonly used in conveyor rolls, contact rollers, and grip pads that gently handle products. This range offers enough cushion to absorb shock yet is stiff enough to resist wear. In fact, many roller covers and fixture pads use ~70–85A urethane to combine grip with longevity.
- 80A–95A (Firm Isolation Spacers): The hardest urethanes (80–90A, approaching Shore D) deliver maximum rigidity and abrasion resistance. These grades support heavy loads with minimal deflection, making them suitable as spacers, coil support pads, or wear strips under heavy equipment. For example, coil storage pads and heavy-duty wear pads typically use ~80–90A (very stiff) urethane to prevent deformation.
This aligns with industry practice: soft-to-medium (50–60A) urethanes are used for shock/impact pads, medium-hard (70–85A) for rollers and contact surfaces, and the stiffest grades (~80–90A) for heavy-load supports. (Above ~95A, engineers typically switch to Shore D hardness scales.)
For detailed guidance, see our Understanding Durometer page, which explains how durometer affects flexibility, load capacity, and abrasion resistance.
Stock Shapes and Materials
Our urethane gaskets and pads are usually made from stock polyurethane sheets or bars, not molded. Universal Urethane maintains a wide range of cast-urethane stock in multiple hardnesses. In practice:
- Sheet Stock (Primary): Flat polyurethane sheets (available in colors and durometers from 40A to 90A) are the primary source for custom gasket material. Sheets can be die-cut, waterjet-cut, or milled into gasket shapes and sealing strips of any outline. The standard urethane sheet is abrasion- and chemical-resistant, ensuring that gaskets won’t wear out quickly or degrade in contact with oils or solvents.
- Rod/Bar Stock: Solid rods and bars of urethane (cylindrical or rectangular) are used for spacers, pins, or bumpers. These are machined into bushings, spacers, and custom pads. For example, bars can be turned on a lathe into non-marring bumpers or isolators that fit shafts or housings.
- Other Shapes: We also offer tubes and blocks, which can be machined as needed, but sheets are by far the most common for gasket and pad production.
Cast urethane sheets, bars, tubes, rods, and blocks in multiple formulations are kept in stock for cutting and machining. This in-house availability means fast turnaround and consistent material quality.
Thickness recommendations
Urethane gasket materials are available in many thicknesses. Standard sheets come in thicknesses from ⅛″ (0.125″) up to 4″. In practice:
- Thin Layers (1/16″–1/8″): Use thin sheets or multiple lamination layers for sealing strips and gasketing. Thin urethane provides high flexibility and conformability, ideal for tight sealing at low compression.
- Thicker Pads (1/4″–1/2″): For contact pads, bumpers, and spacers, thicker stock (¼″ to ½″) is common. These provide more cushioning, travel, and shock absorption before bottoming out. Thicker material also spreads load over a larger volume, extending service life under heavy impact.
Universal Urethane’s shop inventory includes thicknesses (1/8″, 3/16″, 1/4″, 3/8″, 1/2″, 5/8″, etc.) up to multi-inch blocks. Customers may stack thin sheets if an intermediate thickness (like 1/16″) is needed.
Requesting a Quote: What to Specify
When you request a quote for urethane gaskets or pads, please specify the following details:
- Thickness: Desired material thickness (or number of laminate layers).
- Sheet Width & Length: Dimensions of the gasket sheet needed.
- Durometer (Hardness): Target hardness (A or D scale) for the application.
- Quantity: Number of pieces or square footage required.
- Intended Contact Surface: Describe what the urethane will contact (e.g., glass, metal, ceramic). This helps select the right formulation and finish.
Providing these inputs lets our engineers recommend the optimal urethane grade and processing. (For example, if a pad must grip polished metal without leaving marks, we might suggest a slightly softer, low-friction compound.)
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