Standard thicknesses from 1/16” to 1”
F-1: maximum durability, high density, extremely resilient; recommended for critical strength and hardness requirements and for precision applications with constant abrasion, friction, impact, or pressure; good for oil absorption and retention in non-compressed applications
95% min. wool content, off-white
F-3: extremely durable, high density, similar to F-1 applications
85% min. wool content, off-white or gray
Both F-1 and F-3 are commonly used in gaskets and sealing for aerospace, automotive, bumpers, machine components and vibration mounts.
F-5: high grade, medium-high density, for use where durability and resiliency are required
95% min. wool content, off-white
F-7: heavy-duty, medium-high density; good for consistent impact, movement and pressure
80% min. wool content, off-white and gray
Both F-5 and F-7 are good for dampers, dust seals, grease retainers, noise reduction linings, spacer strips seals, vibration mounts, weather stripping, wipers, and uses where a resilient felt is needed.
F-10: high grade, medium-low density, similar to F-5, exceptional grease and oil retention, especially in less harsh environments and where impact and pressure are not significant; recommended for fluid storage and delivery, plug filters for air and gas, and resilient cushioning
95% min. wool content, off-white
F-11: medium to low density, similar to F-10 where resilience is less critical; typically used for acoustic and sound-dampening applications, dash liners, dryer drum seals, and impregnated packings
87% min. wool content, gray
F-13: low density, useful for sound-dampening and variety of mechanical applications where resistance to abrasion and wear are not important requirements
55% min. wool content, gray
F-15: low density, similar to F-10; commonly used for absorbers, cushioning and protective padding, fuel oil filters, sound-dampening and acoustic applications, spacing strips
55% min. wool content, gray
F-26: low density, useful for packing, cushioning or other non-mechanical applications when held between other materials
45% min. wool content, gray
F-50: high grade, high density, similar to F-1 but with two standard thicknesses of 3/64” and 3/32”, typically used for feeding light or low viscosity oil and mechanical applications where precise, thin, smooth, durable material is needed
95% min. wool content, off-white
F-51: high grade, high density, similar to F-3 but with a standard thickness of 1/16”, useful as bearing seals, gaskets and liners or in mechanical applications similar to F-50 where a precise, coarse material is needed
92% min. wool content, gray
F-55: moderate density, similar to F-7 but with standard thickness of 1/16”, good for sound-dampening applications and insulation lining laminated to other materials
75-80% min. wool content, gray and black
Felts are classified by wool content, durability, hardness and tolerances. Wool content is measured by the percentage of raw wool in the felt. Density is a major differentiator among types of wool and determines the material’s stiffness. Higher density SAE felts can resist pressure and wear longer. Tolerances can be adjusted based on wool content and fiber density. As temperatures cause wool to swell or shrink somewhat, changing the thickness and weight of the fiber can generate a slight dimensional tolerance.