Dimensionally altering metal can be a challenging processes, but these range of techniques provide valuable ways of creating structural and voluminous forms. Hammers and stakes are ideal for forging. Choosing the right hammer for the job is important, because the shape of the hammerhead directly influences the direction in which the metal will move. Round, domed heads will punch metal out in all directions, whereas cylindrical faced hammers, such as raising and creasing hammers, will displace metal at right angles to the axis of the cylinder. The choice of stake also has an effect on the outcome of forging – domed stakes can be used to exaggerate the effect of hammering, or for certain jobs will help avoid the hammer hitting the stake. Forging works because of the “plastic” properties of metal, which causes the metal to permanently displace when it is hit. Silver, copper, and gold can all be forged. Aluminum may be forged, up to a point, but it is liable to crack if overworked. Steel has to be forged while it is red-hot.
Hydraulic and rotary presses (pictured) are also popular forming methods. Press forming can be done in a large vise, but achieving the same effects as a press can only really be used for smaller shapes. Dies are used for pressing (usually made from 3/8 in thick acrylic sheets with a pierced hole). If many identical forms are to be produced, a brass plate with a matching hole can be stuck to the surface of the acrylic to help make the die more durable. Medium density fiberboard can also be used to make dies, but will not be as durable. Silver and copper are the most suitable metals for this technique as they are soft enough to move well, and durable enough to cope with the pressures involved.