process used to produce large sheets of ePTFE at scale is a tape stretching process through the following steps:

# A lubricating agent (often an oil) is added to fine PTFE powder until a paste is formed.
# The paste is extruded into a sheet that is calendered to obtain a specific, uniform thickness.
# The PTFE sheet passes through an oven set to an elevated temperature (often around 300C) while simultaneously undergoing an applied stress that dramatically stretches the material.