polymer molecules together ). Sintered : A mixture of powdered metals is heated to the melting point of the metal that has the lowest melting point , until they meld together . Most good quality pads are made in a vacuum furnace : the metal mix is placed on copper plated backplates and these are put on a large circular graphite tray . Trays are stacked up to a metre high then put into the furnace . The air is then pumped out of the furnace and the trays heated in a four-hour cycle : this includes heating up to the correct temperature ( normally 800-1000 ° C ), maintaining this , then applying pressure via a hydraulic ram to help form the pads . Lastly , the trays are treated with nitrogen and left to cool . Some cheaper aftermarket pads use brazing , where the pad material and backplate have a filler metal / alloy layer between them , which is heated by passing through a conveyor belt furnace , thus only sticking the pad together .

What different materials are used ? Some good quality sintered pads can contain six to nine different materials ( e . g . copper , tin , graphite ( carbon ) and mullite ) for better heat absorption , friction modifiers ( to tune the

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