The recommended materials for trough and runner backup shapes are normally Metcast FA7 or Metpump HP4 depending on the specific application. Resin bonded carbon shapes may also be used for special applications. High alumina shapes may be used where oxidation is a problem. Pre-formed skimmer blocks are made from FA7, HP4 and from "sandwich blocks" where the inside of the skimmer is a carbon block and the outside is FA7.
Form being installed.
Pre-formed bottom shapes are set.
Pre-formed sidewall shapes are set.
Main runner is ready to be pumped.