raden wrote:
I have an impulse sealer (for heat sealing plastic bags) and it's no
longer supported by the manufacturer, which means that I can no longer
get the woven teflon material which goes between the heating element and
the plastic bags to seal

If it's a bag sealer (i.e. a narrow heated line), then it probably
needs PTFE or graphite cloth. It's still available (you didn't think
the sealer manufacturers wove it themselves, did you?) but not cheap,
or available in handy sizes from cheap shops. RS might carry it, as do
the better engineering or lab suppliers. Last time I bodged something
with it I had to unravel some woven PTFE rope that was intended for use
as a valve seal.

If it's a laminator (wide area) then the peak temperature is usually a
bit lower and you can get away with Kevlar. This has the advantage of
not wearing out.