What is a soldering and brazing mat made from?

3rd March 2020

What is a soldering and brazing mat made from?


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		A soldering and brazing mat offers thermal protection from heat, direct flame, fire and molten metal splashes for most types of surface. The material used will need to have excellent high temperature and fire resistant properties.

		A typical soldering and brazing mat will be made from a combination of high temperature yarns, each having their own individual temperature resistance rating. The choices include: 1. Glass fibre 2. Silica fibre 3. Ceramic fibre 4. Carbon fibre

		How is the fabric made?
		Most mats are made from woven fabrics, which are produced by weaving one of the above fibres with another. You will, however, find the occasional mat in a non-woven fabric, usually using carbon fibre combined with another. The exact combination is a closely guarded trade secret.

		Woven fabric A woven fabric is created when two sets of fibres are bonded together by being interlaced at right angles to each other. A soldering and brazing mat made from woven fabric will usually use a plain weave. The yarn is entwined to form a simple, criss-cross pattern compared to the more complex weave patterns of other woven fabrics.

		A soldering and brazing mat in a plain weave is strong, rigid and hard wearing – it is ideal for protecting flat surfaces such as a table or a wall.

		Non-woven fabric A non-woven fabric is a fabric which has not been woven or knitted, for instance, felt. Instead, the fibres are pressed together with an adhesive, a chemical binder, heat or interlocking the fibres using serrated needles, for example.

		An example of a non-woven soldering and brazing mat is needle felt. A combination of carbon fibre is bonded together with other yarn using a needle punch loom. The fibres are mechanically interlocked using numerous needles with sharp points, which literally tangle the yarn into felt.

		Soft, pliable and scratch-free, a needle felt soldering and brazing mat is suitable for shielding decorative surfaces such as painted, lacquered tables or floors. Or for silver soldering fine, delicate pieces of jewellery. Carbon fibre has an extremely high temperature resistance rating and is also suited to industrial applications such as furnace brazing.

		The yarn
		1. Glass fibre (also known as fibreglass cloth, glass cloth)
		Glass fibre is a material made up of numerous fine strands of glass. Aside from strength, one of its most notable qualities is a high tolerance to extreme heat, which travels across the fabric rather than through it. These glass fibres are interwoven with the filaments of another high strength yarn to produce woven glass cloth, capable of withstanding continuous temperatures up to 540°C.

		2. Silica fibre (silica cloth)
		Silica fibre is a long thin thread made of silicone silicate or liquid glass, which undergoes a chemical and heat process to form silica fibres. Silica cloth resists molten metal splatter especially well, providing a continuous temperature resistance of up to 1,100°C and short bursts of 1,400°C.

		3. Ceramic fibre (ceramic cloth)
		Ceramic fibre (a synthetic wool) is woven with another heat resistant reinforcing yarn, usually either glass fibre or stainless steel wire wool. Ceramic cloth is also renowned for not shrinking when used within its continuous temperature range. The working temperature of ceramic cloth is affected by which reinforcement is used.

		If combined with glass fibre, the continuous temperature resistance is a maximum of 550°C.

		If blended with glass fibre filaments and stainless steel wire, the limit rises to 1,260°C.

		4. Carbon fibre (carbon cloth)
		Carbon fibre consists of processed filaments of the element carbon, a primary substance which cannot be broken down further. Strong and resistant to chemicals, carbon cloth has a continuous high temperature tolerance of 1,200°C.

		Finishing treatments
		In addition, these high temperature fabrics – usually glass fibre cloth – may also undergo a finishing treatment to enhance the thermal properties of the base cloth as well as adding extended life. This is generally one of three treatments: a. A graphite treatment b. A calcium silicate treatment (also known as a silica wash) c. A vermiculite treatment

		Graphite treatment (usually referred to as Graphtex) With a Graphtex treatment, the cloth is coated with a complex graphite/silicon solution to increase its temperature rating as well as its resistance to abrasion, which acts as an armour to the cloth. Black in colour, graphite / Graphtex cloth provides a continuous temperature resistance up to 700°C and a short temperature resistance of 800°C.

		Calcium silicate treatment The cloth is treated to a specially formulated calcium silicate solution providing maximum protection against direct flame and molten metal splashes. A calcium silicate coating comes in various colours, withstanding continuous temperatures of up to 800°C and short temperature bursts of 1,000°C.

		Vermiculite treatment With this finish, the fibres are treated with vermiculite (a mineral) in a liquid form, which safeguards against burning from molten metal splashes, direct flame and sparks. A vermiculite treatment, usually gold in colour, provides a temperature resistance up to 815°C of continuous exposure and up to 1,000°C of short exposure.

		And finally…
		When choosing a soldering and brazing mat, you will notice that manufacturers give limited information about the materials used in their product, if any at all. Other than disclosing that their mats are asbestos-free, some manufacturers will only reveal their brand name, keeping details of the fabric confidential. All relevant product information should be found on the packaging.

		Here at Wonkee Donkee, we have done our best to provide as much information as possible on the type of high temperature fabric and treatment used with the limited information manufacturer’s provide. While it is interesting to learn about the various textiles, it is the temperature that the mats can withstand which should be the main concern. It is not really a question of choosing a yarn over another; it is primarily about choosing a temperature rating suitable to the application.

		In this respect, when choosing a soldering and brazing mat, check that the continuous temperature resistance rating is suitable for your project or application. For more information on choosing a soldering and brazing mat, please read our pages: Which soldering and brazing mat should I choose? and What are the different types of soldering and brazing mats?