How do you solve the problem of producing a limited edition of hand wrought, hollow forms in a reasonable amount of time, and yet have them fit together and look fairly identical without looking machine made? Raising, chasing or masonite die-forming might be an answer, If you are fast and accurate enough at it. But even then, those methods can't compare with the speed, ease and precision offered by the inexpensive, simple, practical forming of such pieces by use of dies and a small hydraulic press.
The equipment used is simple to build and the processes are easy to master. Using this process, you can quickly form sheet metal into hollow forms that fit together for soldering with a minimum of work and almost no finishing or loss of metal, thereby allowing the use of a thinner gauge metal. Hang in there and we'll cover how to do it all, but for a moment take a look at how it all developed.
Die-forming of sheet metal originally began thousands of years ago, by utilizing crude grooves carved into stone or wood, into which the metal was freely manipulated by hand and hammered into the depression. Dies were used for handles, spouts and forms that couldn't be made on stakes.
Within the last 150 years, however, die-forming concepts have undergone a tremendous technological evolution. Most important was the creation of mate-female conforming dies to create hollow forms utilizing hydraulic pressure or drop hammer presses. (The terms "male" and "female" conforming dies are standard industrial jargon for dies which conform in shape... the symbolism is obvious.)
Today, hydraulic pressing and stamping of dies are used very extensively throughout industry to form everything from pots and pans to automobile bodies. Nonetheless, very few individual artist-metalsmiths have utilized this technique on a small, inexpensive scale to produce forms in silver or gold.
To adapt hydraulic pressing equipment and techniques to a small, inexpensive scale, experiments were conducted using an adapted version of the original masonite die technique which was developed by Richard Thomas of Cranbrook Academy of Art. A small, war surplus, embossing Press was originally used. This research was initiated by Ruth Girard at the University of California at Berkeley, in 1971 and led to eventual development of pourable epoxy-steel molds on a small wale. I have continued the research since that time, and wish to share the results with you, now.
Hydraulic pressing of conforming dies starts with a 3-dimensional model or pattern which is used to mold male and female dies which conform in shape, to the model and each other. The dies are then inserted in the press and sheet metal is placed between the dies. Then hydraulic pressure is applied, in order to press the metal into the desired form. Industrially, most dies am made of steel or pourable epoxy-metal material and the presses are commercially purchased and can generate a pressure up to 3, 000, 000 lbs. per square inch' Needless to say, equipment and dies like that could cost a mint.
Therefore, adpating the processes for our use, involved making an inexpensive press as well as dies. Utilizing the adapted techniques, you can press gold, silver, copper or brass sheet metal ranging from 24 Ga. to 16 Ga., with little trouble. 24 Ga. is the upper limit, since metal any thinner tends to tear, krinkle, crimp or fold in pressing in these molds. Metal thicker than 16 Ga. creates a need for extreme hydraulic pressure as well as a more sophisticated mold, made of steel. Nonetheless, this range of gauges seems to encompass most of the hollow forms work done by artist-metalsmiths.
Sooooo, let's take a look at how to make a press and dies.
It you have the money, you can purchase a fine, commercial, hydraulic press for about $1 000 or you can make a suitable am of your own for under $50 and some elbow grease. Essentially, all the press consists of is a strong steel frame into which a hydraulic ram is inserted and used to press one of the dies against the other.
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