Herman Bergman Fine Art FoundryTechnical overviewMould making - A silicone mould is made from the artist's original. This mould is used to make a hollow wax reproduction of the original. En silikonform görs efter konstnärens original.Cire perdue - Lost wax - Hot wax is brushed into the mould parts. These are assembled and wax poured in, joining the parts.Wax chasing - When the wax has cooled, the wax reproduction is taken out. And then the moulded joints and other defects are retouched or "chased" away.Spruing & Gating - Then wax sprues and gates is soldered on to the wax reproduction, in a system that allows bronze to flow into and fill the mould of the sculpture.Investing - After the wax reproduction is coverd by sprues and gates, it is invested (covered) in either a slurry and ceramic sand or our own castable ceramic investment.De‑waxing - The mould is then baked in the oven, at about 750°. The wax flows out, leaving a hollow cavity in the mould. Which has now become sintered ceramic and thus will withstand the 1100° liquid bronze.The sand mount - The sand mount is usually done with oil or water based sand and decides where the part line goes. The sand casting technique is a direct imprint technique, this means that the cast mould is made directly against the original sculpture.Piece sand mould - The whole original is covered by a piece mould. Somtimes alot of pieces due to the complexity of a sculpture, as in a large 3d puzzle. This is done to make it possible removeing the original, aswell as to keep alot more deatail than normal sand moulding. The pieces are made by hand to ensure not to damage the original.Core-Making - When the outer mould parts are completed, a inner form is made "the core", leaving a gap between the outer and the inner mould for the bronze to fill. The core is Built around a skeleton of iron rods. Suspending the core, in the void created by the outer mould.Casting - The pour - The hot moulds are strengthend by steel bands, and packed in sand, for personal safety as well as for quality. Obtaining outstanding results demands a fault free pour.Devesting & Cleaning - Deveting is the process during which the invetment is removed from the bronze. Skill and strength are combined with axes, hammers and power chisels.To remove the ceramic still stuck to the bronze. Sprues and gates are cut away and the casting is sandblasted clean to minimize damage to the chasing tools.Welding & Assembly - When sculptures are cast in multiple sections the parts is welded, solderd or assembled by screw joints. Welding is also the main tool to rectify cast defects and cast technical "holes".Bronze Chasing - Chasing is essential to take down welds and to address the slight imperfections that may from the casting or shell building process.Patina & Waxing - The bronze sculpture is oxidized with acids, salts and other chemicals giving the desired look. Sometimes less orthodox methods also are used depending on the sculptors wishes. Usualy ending with a protective wax layer for durability and shine.Installation - The sculpture is placed, positioned and anchored to the ground.Maintenance - Maintaining a sculpture is important. Gennerally washing and waxing is recomended each other year for outdoor sculptures, this however is more important in the begining. When the sculpture is older than about 10 years we recommend each 6th year. Smaller damages like scratches and broken off pieces are repaired.