Seams are then stick welded with polyethylene rod/wire .... very common as with repair of (snow) ski bottoms, then spark test to ensure integrity of plastic weld.
Many (most) epoxies leach considerable extractables unless USFDA grade ... and that stuff is beyond super expensive. Even the best epoxies still issue large doses of extractables that I consider to be too high for potable water
, especiallly on long term storage
. If epoxy
was more compliant to potable grade and long term storage
of water I'd use it in a minute. Because of the high extractables ... thats the reason for lining with polyethylene. The real problem with polyethylene is that it is only suitable for mechanical attachment and epoxy and or other resins will not bond. The stuff Im looking for has a surface scrim of polyethylene into which styrene or epoxy can lock and make a mechanical bond.