Wool Content

Wool percentage is based off of new wool in the felt. The remaining fibers are made of something called card waste this can consist of anything including recycled wool, cotton, rayon/viscose (wood fibers) and even bits of vegetable matter and synthetics. This material is used as filler to either reduce the cost of the felt or impart certain desired characteristics to the finished material.

Density - Stiffness/Hardness

Density, which determines the hardness of the felt, is one of the main characteristics between the different SAE felt grades. Here is a list from stiffest/hardest to most pliable/softest:

F-1 / F-3 / F-50 / F-51
F-5 / F-7 / F-55
F-10 / F-15
F-26

Tolerances

Tolerances in SAE felts are based off of the wool content and density of the fiber. Wool is prone to contract or swell slightly depending on temperature, changing the thickness and weight of the fiber. Cutting the wool can also shrink the fiber creating a slight dimensional tolerance.

Applications

Some popular applications include, but are not limited to - anti-vibration pads, floor and furniture protection, acoustic paneling and sound absorption, musical instruments (mallets and xylophone), equestrian saddle pads, speaker felt, interior design, gaskets and seals, packing, and much more.

Durability

Wool fibers have small barbs on them, which allow them to interlock when being felted. The more friction, moisture and pressure is applied during the felting process, the denser and more durable the felt becomes. High density SAE felts have the ability to withstand long periods of wear and pressure.

Color

SAE felts are made from natural sheep wools and not dyed. Similar to human hair, sheep hair comes in a variety of colors, shades and textures. This means that SAE felt colors will vary from lot to lot. For designer applications requiring consistency in color and finish we recommend using 100% wool designer felt instead of SAE felt.

F-1

SAE F-1 Felt has the highest durability of any industrial felt. Highly resilient, F-1 felt is recommended for uses where impact, pressure, friction, and abrasion are constant. Washers, wicks, door bumpers, and polishing blocks are among its many possible applications. While not recommended if you require a soft or pliable material, F-1 is great for low viscosity oil absorption and retention.

Wool Content: Min. 95% wool
Density: High, 0.32-0.36 g/cm³ (539.4-606.8 lb/yd³)
Color: Off-white
Price: $$$

F-3

SAE F-3 Felt is one of the most durable industrial felts with an 85% wool content. F-3 serves the same general purposes as F-1 but is slightly less dense. Its advantages include excellent vibration absorption, resistance to abrasion and wear, and applications that require a coarse wool. F-3 felts is suitable for precision applications such as vibration mounts, precision lubrication wicking, oil seals, bumpers, gaskets, automobile, aircraft and machinery components.

Wool Content: Min. 85% wool
Density: High, 0.32-0.36 g/cm³ (539.4-606.8 lb/yd³)
Color: Natural Gray
Price: $$

F-5

SAE F-5 Felt is a heavy-duty 95% wool industrial felt. Slightly less dense than harder F-1 and F-3 felts, F-5 is an ideal felt for floor mats, seat pads, and other applications that require solid cushioning. Its other applications include dust shields, wipers, grease retainer washers, wicks, and vibration mountings.

Wool Content: Min. 95% wool
Density: Medium-High, 0.25-0.27 g/cm³ (421.4-455 lb/yd³)
Color: Off-white
Price: $$$

F-10

F-10 Felt is an SAE grade industrial felt made with a minimum wool content of 80%. F-10 is recommended when you require excellent grease and oil retention in your application. This felt is also great for dust shields under less severe operating conditions and where pressure and impact are not important factors. Its crafting uses include storyboard walls, seat cushions, and embroidery protection.

Color: Off-white
Wool Content: Minimum 80% wool
Density: Medium-Low, 0.17-0.20 g/cm³ (286.5-337.1 lb/yd³)
Price: $$$

F-15

SAE F-15 Felt is suitable for the same applications as F-10 felt, but has a slightly lower wool content. Applications include sound deadening chassis strips, spacers, dust liners, and for mechanical purposes where abrasion and wear are not important factors. Other applications include acoustic panels, protective padding (such as saddle pads, blankets, and cutting table protectors) absorbers, packing material, sound dampening insulation, and cushioning material.

Color: Natural Gray
Wool Content: Minimum 55% wool
Density: Low, 0.17-0.20 g/cm³ (286.5-337.1 lb/yd³)
Price: $$

F-26

SAE F-26 Felt is an industrial wool felt with low density. While this grade of felt is not recommended for mechanical applications, it is ideal for packing or padding when held in place between other materials. Non-mechanical applications include crate liners, sound absorption, sports equipment padding, and padding between parts.

Color: Natural Gray
Wool Content: Minimum 45% wool
Density: Low, 0.14-0.17 g/cm³ (236-286.5 lb/yd³)
Price: $

F-50

SAE F-50 industrial wool felt is a highly dense felt, similar in density to F-1, and best suited to applications that require an accurate, thin, smooth high-grade felt. This felt grade is also used for ball and roller bearing oil retainer washers and small dust-excluding washers. Use this felt in installations where it will not be compressed, for feeding low viscosity or light oil, and where strength, durability, and hardness are required.

Color: Off-white
Wool Content: Minimum 95% wool
Density: High, 0.32-0.36 g/cm³ (539.4-606.8 lb/yd³)
Price: $$

F-51

SAE F-51 Felt is a high-density 92% gray wool industrial felt. F-51 felt is similar to F-3 felt but made in thicknesses less than 1/8 inches and used where a thin, high-grade wool felt is required. Common applications include ball and roller bearings, oil retainer washers, and smaller dust excluding washers. We recommend it for applications where an accurate, coarse felt is required.

Color: Natural Gray
Wool Content: Minimum 92% wool
Density: High, 0.32-0.36 g/cm³ (539.4-606.8 lb/yd³)
Price: $$

F-55 Black

SAE F-55 felt is a moderate-density felt used for anti-squeak strips and for lining cemented to fiberboard or metal panels. F-55 felt is also used in similar applications as F-7 felt, when the thickness required is less than 1/8 inches. Other applications include dust shields, gaskets, lubricators, acoustic material, wicks, and wipers.

Color: Black
Wool Content: Minimum 80% wool
Density: Medium-High, 0.25-0.27 g/cm³ (421.4-455 lb/yd³)
Price: $$