Air Set Casting from the Butler Foundry

Air Set Casting

Air set moulding was developed as a production process to help compensate for the ever-increasing demands of the casting buyer. Air set sand moulding produces a sand mould of considerable strength, which can be free standing without the need for moulding boxes and therefore unlimited in size.

The process requires graded kiln dried sand, which is mechanically mixed with a resin to bind the sand together. A chemical hardener is then added to the sand mix, which reacts with the binder and begins to set the sand into a solid form. At this point the fluid sand is rammed around a pattern or multiple patterns. Once rammed the sand is left to set. Setting time being dependent on the type of hardener used, be it a 3-minute hardener or a 30-minute hardener. The sand literally sets into a solid block from which the pattern equipment is drawn. Cores are then added to the mould and the mould closed ready for casting.

Air set moulds allow for much larger, intricate castings to be produced. A solid sand structure allows the mould to be literally built from its individual pieces. Castings of complexity can be produced which may otherwise have to be fabricated from individual parts. An air set mould is best suited to larger heavier castings as the mould strength allows for greater weight of metal to be cast, sand use can be kept to a minimum without compromising quality so production costs are reduced.

W H Butler uses state of the art foundry equipment on its air set line, which allows 100% reclamation of the primary raw material, sand. This reclaimed sand is broken down, cooled and filtered, to be used again and again. To maintain sand quality and mould strength the reclaimed sand is mixed with new sand at a ratio of 75%: 25% respectively. This process keeps production costs to a minimum without compromising quality.

Being aloof to environmental issues Butlers have found a useful outlet for its waste sand. The sand is taken free of charge from site and used in other production processes eliminating dumping costs and therefore making savings which can be passed on to the casting buyer.