Casting Techniques
Highly developed material & chemicals for goldsmith's, dental laboratories & gold-silver and platinum casting factories. Continual research & development, use of innovative techniques, castings can now be made in original size and surfaces, copying micrometer structures.

Heinrich Butschal GmbH München - Germany


Vacuum casting
Highest Quality - simplest solution

Latest scientific results - not only in our lab, but in the science Institute for Precious Metal recent studies show that the quality of casting is not dependent upon the method of casting or the equipment. At the latest symposium in Vicenca, Professor Ott repeated that no casting machine whether gas pressure, Argon-protected melting or centrifugal system can hinder crystallization and avoid development of pores and shrink holes.

Claims contrary to this should not be taken seriously. The strength between the atoms during crystallization work many thousand times stronger than any pressure put on the casting from outside. The tests that I have carried out, have shown other factors as the cause of pores and shrink holes.

To control the crystallization process I have developed a wide range of helpful aids: (anti shrink hole Paste, degassing powder, smelting alloy, and Castin). With these additives, one has the capacity to produce castings with perfect surfaces and tenseness. Now I have produced a simple, functional and practical piece of casting equipment that fills all casting requirements in the best possible manner. For small flasks it yields results comparable to the centrifugal system, and for larger flasks (4 inch or larger) it yields excellent results.

The principle of the system is that the atmospherical air pressure is enough to press the metal into all corners of the form. For this, in the housing cabinet, low pressure is obtained. This can be done with a vacuum pump or for simple designs (not filigree) even the nose of a vacuum cleaner can be used. A flask should be filled with investment, (not quite full).

After burning out and cooling for casting temperature it should be placed on the Vacuum machine, open end up, the machine then turned on and the molten metal poured into the mold. Nothing is easier.

Whilst the vacuum is switched on before casting, all mishaps usually encountered by the novice casters with similar casting methods (pressure or damp pressure casting like potatoe-casting) are avoided. When larger flasks with several pieces are required one should stick wax or wood sticks to the flask walls before investing. These sticks burn out with the wax and give better suction and more even results

. Particularly fine, hard to cast pieces can be treated in this way by placing several sticks in the problem area. All sizes and forms of flasks can be cast (from 1/2 inch to 12 inch diameter), and as crystallization take only minutes, the performance is immense. For the smaller workshop as well as industrial production this casting machine complains value for money along with efficiency.

A new machine for Vaccum casting and Plastic-vaccuum-forming

see original size