Wool Felt and Felted Synthetic Materials
Felt in its many forms can be your best solution for product design challenges.
Wool felt is one of the world's oldest man-made fabrics because it does not require weaving. Instead, it interlocks to form a continuous useful material. Through a process of manipulating, hammering, and steaming, scales on the wool felt fibers engage each other to form a lasting, resilient bond. The natural fibers in wool felt cannot be duplicated in the laboratory. Each wool felt fiber has a flexible microscopic covering of scales similar to the scales on a fish. Wool felt scales are made of keratin, the same tough substance that grows to form horns and hooves on cattle and other animals.
Keratin scales give wool felt fibers several advantages:
- They trap air to make excellent thermal insulators.
- They are extremely resistant to wear.
- They promote capillary action for wicking liquids.
- They form resilient bonds to absorb vibrations and shocks.
- They facilitate homogeneous penetration of chemical treatments.
Today wool felt material is manufactured to a wide range of specifications:
From .025" to 3.00"
From .08 grams/cc
From 75 psi
Wool felt is amazingly durable
- It resists aging.
- It remains dimensionally stable for decades.
- It functions normally in temperatures ranging from -60°F to 180°F. Even up to 250°F, if allowed to regain its natural moisture periodically.
- It is inert to most hydrocarbons as well as most other chemicals. It even resists acids. However, wool fibers can be damaged by alkaline substances.
- It does not ignite easily and usually extinguishes itself unless exposed to constant temperatures above its ignition point.
- It holds its strength and resilient properties. Wool felt can be stressed to just under its elastic point repeatedly for years and still snap back to its natural shape. Piano hammers are a good example of this characteristic.
- Felt can be machined. It can be cut, ground and formed like metal in appropriate densities.
- It can be die-cut into intricate, high-precision shapes.
- It can be heat formed.
- It can be bonded to almost any surface.
Other Types of Felt
While wool felt is mostly pressed as described above, there are more ways of making it from wool and even some synthetic fibers.
For example, wool and other fibers can be felted in a process called needling . The products of needling are in a category of materials known as non-woven textiles.
Needling is a process that involves working fibers with a bed of needles that engage and disengage the fibers until they become interlocked to form a textile. Wool and a variety of synthetic fibers can be needled to form useful materials in various thicknesses and densities.
A third way of making felt is to form a thread of the fibers and weave them. Woven felts are known for their resiliency and flexibility. Well known applications include game table felts and certain wicking parts.
Wool Felt Wheels
Felt wheels are available in soft, hard, and rock hard densities for applications ranging from glass to metal surfaces.
Wool Felt Filtration Media
- Fuel filters
- Air filters
- Vapor filters
Wool felt can exclude particles down to 0.7 micron.
It is adaptable to virtually any filter configurations. Plugs, accordion-pleated cartridges, sewn bags, and drum heads are among the most common. However, the versatility of felt lends itself to unusual and critical filtration situations.
Wool Felt for Vibration Absorption
- Mounting pads
- Shock absorbers
- Vibration dampers
Wool felt absorption mounts can reduce the vibrating energy of machines by as much as 85% with proper application. Sensitive instruments can be similarly protected from floor and counter vibrations.
Wool felt used in vibration isolation felt is durable and stable in the presence of moisture, lubricants, greases, detergents, salts, and chemicals. It conforms to uneven surfaces to block unwanted foreign material from the load bearing area.
Wool Felt holds up for years under heavy static and dynamic loads without deterioration. This holds true at low temperatures where some materials become hard and brittle.
Wool Felt for vibration isolating applications is available in various densities and thicknesses for mounting light or heavy loads in the range of 1-to-250 psi.
- Industrial sound dampers
- Speaker enclosure linings
- Noise hood liners
Wool felt absorbs more sound per thickness than other materials making it the leading choice in applications where space is limited:
- From 50 - 1,000 cycles per second
- 3/8” felt, 18 density = 1" fiberglass batts = 2 1/2" crimped paper batts
- Filter media
- Protective Packaging
- Finishing Pads
- Cleaning Pads
- Polishing Pads
- Deburring Media