that covers insert 20 in a manner to allow contact between the sheets 30 30 u2032 along portions of the polymer inside the entirety of insert id 22 and outside the insert od 24 heat and pressure can then be applied to one or both sheets 30 30 u2032 to unify them in one example sheets 30 30 u2032 are pressed together at about 650 f degrees and two three pounds per square inch u2018 psi u2019 of contact stress sections of expanded ptfe sheet are placed around a stainless steel insert that is smaller than the squares the components are transferred to heat press platens 35 the air pressure in the compression cylinder applying load to the platens is adjusted to the pressure necessary to develop two three psi stress across the square sections of expanded ptfe and the top and bottom platens are brought together around the components a programmable logic controller is configured to ramp up the heat of the platens to 650 f at a rate of approximately 10 degrees per minute once at temperature 650 f the components are held at this temperature under the two three psi stress for a minimum of 5 minutes after 5 minutes the platen heaters turn off and the entire fixture is cooled to about 210 f degrees while under load at 210 f or lower.