The Koskenpää felt selection includes a hundred types of felt. Felt can be made from various fibers, both synthetic and natural and can be produced either industrially or by hand. When referring to craftsmanship, the process is called felting, while in industrial production, it is simply referred to as the manufacturing process. Handcrafted felt is most often made exclusively from wool fibers.

In industrial felt production, we adhere to two primary methods: needling and fulling. Wool felt is made through fulling, a process that mirrors traditional hand-felting techniques—simplified to moisture, heat, and movement.

Needling, on the other hand, relies on dry felting. The barbs on the needles interlock the scaly fibers without the need for water, creating felted non-woven structures. This method has enabled the use of various synthetic fibers and expanded the versatility of industrial felt production.

The wool felts in Koskenpää’s selection are produced using the fulling method, while synthetic felts are most often made through needling. Even in fulled felts with fiber blends, wool typically constitutes the majority of the material. Koskenpää Felt Factory’s KH sealing strip, a low-density polypropylene felt, is also made using the needling method.

Sewing felt

Felt with a thickness of 1–3 mm is easy to sew using a standard home sewing machine. From 3 mm upwards, the space under the presser foot can become tight. You can find a table on felt sewability in this PDF.

Care instructions for felt

Colored wool felts

The S-collection felts are treated with a dirt- and moisture-repellent finish to prevent staining. Additionally, the dense surface of wool felt is naturally water-resistant. If the felt becomes heavily soiled, dry cleaning is the most suitable method of cleaning. For felts that are suitable for wool washing, it’s worth trying a wool wash cycle first, depending on the severity of the stain. High-quality steam cleaners can also be effective for cleaning.

For light dirt, try wiping with a damp cloth, or for dry dirt (such as dust, crayon, or chalk), use a vacuum cleaner. Gentle vacuuming is generally a suitable cleaning method.

If the felt is placed in an area where it may pill, any resulting pills can be removed by hand, with a fabric shaver, or using a cashmere comb. Scissors are also an effective option for removing pills carefully.

Felt also benefits from fresh outdoor air, so airing it out is recommended when possible. Regular textile protectants are generally suitable for felt, but it’s always best to test the product first in an inconspicuous area.

All wool felts can be ironed at low heat (below 110°C), preferably through a damp cloth.

Villakuidun ominaisuuksia

The elasticity of wool’s molecular chain contributes to its resilience. Wool’s natural flexibility is greater than any other fiber. It has a unique ability to return to its original shape, which significantly enhances comfort. Wool garments conform to the body, providing freedom of movement, while wool fibers in carpets remain resilient for years.

Wool has excellent moisture absorption properties while also repelling water. Its natural greasiness and the scales on its outer layer make it water-repellent. At the same time, microscopic pores in the fiber allow water vapor to pass through. Wool can absorb moisture vapor up to one-third of its weight without feeling wet. When wet, wool generates heat, so it doesn’t feel cold, even when damp.

Thanks to its moisture absorption, wool insulates against both heat and cold. Its crimped fibers keep them separated, creating tiny air pockets that act as excellent insulators. The curliness of wool also contributes to its insulation capacity—the curlier the wool, the more air it traps. Air is one of the best natural insulators available.

In cold weather, wool fibers absorb moisture, keeping the skin dry. A dry air layer forms between the wool and the skin, working together with the air pockets between fibers to maintain body warmth. In hot weather, the absorption process helps keep the body cool. Perspiration is the body’s natural cooling mechanism, and wool cells absorb body vapor, lowering the body’s temperature. At the same time, wool’s air pockets insulate against external heat, stabilizing the body’s temperature.

Wool has a natural ability to resist static electricity. Because it absorbs moisture from the air, its tendency to generate static electricity is reduced. This property contributes to wool’s dirt-repelling nature. Without static electricity, wool does not attract dust or lint from the air. Additionally, the scales on the outer layer and the fiber’s curl prevent dirt from penetrating the surface.

Wool is naturally fire-safe and does not require special treatment. It is difficult to ignite, and if it does catch fire, it will not flare up or sustain a flame. Wool does not melt when burning and has excellent self-extinguishing properties.

The abrasion and wear resistance of wool fibers is generally not high. However, medium-fine wool, obtained from the sheep’s outer coat, offers the best durability. Factors such as heat, sunlight, microorganisms, and chemicals affect the strength and abrasion resistance of wool fibers.

Sources:

Jokela, Iina (2006): Thesis in Finnish, English summary
Mielonen S 2005a. Merino. FILTTI Suomen Huopayhdistys, jäsentiedote 1/2005
Mielonen S 2005b.Villakuidusta tietoa. FILTTI Suomen Huopayhdistys, jäsentiedote 2/2005
Ågren K 1981. Huopatyö, eli miten villasta tehdään huopaa. ICA-förlaget AB. Kustannusyhtiö Otavan painolaitokset, Keuruu.

Synthetic felts

Synthetic felts produced through needling commonly use white polyester fibers. Other frequently used fibers include polypropylene and viscose. Viscose is a cellulose-based material derived from nature, but as a processed fiber, it is not classified as a true natural fiber like cellulose. The range of synthetic felts is extensive, and their production can be customized for various needs through collaborative development efforts.

Synthetic felts are widely used in industries such as automotive and metal processing and are suitable for thousands of different applications. Common uses include industrial conveyors, wipers, filters, and gaskets. The cost of synthetic felts varies greatly, from affordable polyester felts to premium aramid and melamine fiber felts.

Industrial felts can also be manufactured with highly specialized properties, such as high heat resistance, flame retardancy, exceptional abrasion resistance, or even antibacterial features. These properties can be achieved not only through fiber blends but also through chemical treatments. Common treatments include coatings to enhance oil and dirt resistance and the addition of resins to produce rigid synthetic felts. Additionally, the tensile and breaking strength of felts can be improved with support structures embedded in the material.

About different fibers

Polyester is a popular fiber due to its favorable properties, good availability, and reasonable cost. Its features include a working temperature range of nearly 100°C. Polypropylene, on the other hand, offers better chemical resistance, although its working temperature range is lower than that of polyester. Additionally, polypropylene is available in a wider range of colors compared to polyester.

For more demanding environments and applications, felts are made from fibers and fiber blends that include meta- and para-aramid fibers as well as melamine fibers. These materials enable felts to achieve extremely high working temperatures, exceptional abrasion resistance, or flame-retardant and cut-resistant properties. Such felts are often used in metal industry processing or in environments with stringent fire and personal safety requirements.

Here are some instructions and ideas for working with wool felt

Felt Basket

Felt Basket – Ihana Magazine

(Published in Ihana Magazine 1/2011)
Find more creative ideas and projects on the Ihana Magazine website: www.ihanalehti.fi

Felt Insoles

Comfortable and fun felt insoles are perfect for every shoe, whether for summer or winter.

(Published in the Iltasanomat newspaper on February 19, 2011)

Felt slippers

Suuri Käsityölehti has provided numerous patterns for sewing your own felt slippers and mules.

(Published in Suuri Käsityölehti, issue 11–12/2008)
Find countless other ideas and plans in Suuri Käsityölehti—get inspired at www.suurikasityo.fi.

Dyeing White Wool Felt

Leena Sipilä, Felter of the Year 2010, has created instructions for dyeing white wool felt for Huopatehdas.