Hands On Jan s method of creating die forms is both effective and fascinating. Her demonstration includes essential information, such as constructing a well-made die, forming metal with the hydraulic press, and chasing and cutting out die forms, as well as specialized techniques, like using computer software to create mirror images and pre-etching metal to produce a pattern for piercing. 6 Here, three pieces of thermoplastic are cut to the designated die size. I make one layer of the die at a time. 1 I sketched until I was convinced of the piece. 2 I used graphic design software to create the ornamental patterns. Using a computer also makes it easy to create exact mirror images of desired shapes. 3 My dies are made primarily from cast, 1 4-inchthick (6 mm) thermoplastic sheets with 18-gauge brass faceplates. Thermoplastic can be purchased in larger sheets and cut to size. The brass faceplates are helpful in creating asymmetrical forms. Faceplates keep the top edge of the die from wearing. 4 The size of the die is determined by the form to be pressed. The brass sheets for the faceplates were cut to this overall size. It is important to leave an equal border on all sides of a die. Because this die is open on one end, I left a 1-inch (2.5 cm) border on three sides. It is also important that the cutout shape is centered in the die. The two pieces of brass were glued together for sawing accuracy, and a photocopy of the shape to be cut out was glued to one side of the brass plates. When sawing the faceplates, care should be taken to keep the saw blade as perpendicular to the brass sheets as possible. 5 I used a 2/0 saw blade to cut out the faceplates, but I used a 4/0 saw blade to make the rest of the die because I find it more accurate. 7 Using the brass faceplates as a template, I traced the silhouette of the shape onto the first piece of thermoplastic and cut it out. The most important edges on the die are the top edges of the cutout silhouette on the brass faceplates, which have been filed with a slight bevel. It is also important that the edges of the thermoplastic are even with the brass edges, not shorter or longer. 8 Many types of dies can be used with the hydraulic die-forming process. The kind used here is an open-ended silhouette matrix die. It is comprised of two brass faceplates and three layers of 1 4-inch-thick (6 mm) thermoplastic. The layers are secured with thin, double-sided carpet tape. 130 The Penland Book of Jewelry The Penland Book of Jewelry 131
I 9 11 This photo shows the etched metal with a nail polish resist painted around the etched form. tape. This is especially important on the first pressing when the silver sheet could slide around. 15 The requisite die-forming materials must be assembled in the following sequence, beginning 18 After pressing the form, I checked its progress, using the tape as a hinge before removing the form from the die. The fully dimensional form will be achieved through a series of pressings. The metal is annealed in between each pressing. used a circuit board transfer film called PNP-Blue to transfer the surface pattern onto the metal for etching. 10 The toner from the PNP-Blue was transferred to the silver sheet and will act as the resist for the ferric nitrate. The die-forming process as illustrated in this section does not distort or diminish the surface treatments, in this case an etched surface. This particular etch does not have to be deep because the etched pattern is serving only to delineate the pattern for piercing after the volume has been achieved. Transferring an organic pattern onto a fully dimensional form is difficult, and forming a pierced sheet requires special precautions. 12 I used a 20-ton (18.1 metric ton) bottle jack housed in a steel frame with an industrial hydraulic hand pump. In this photo, the bottle jack is in the down position. In subsequent photos, the ram cylinder of the jack will be extended, and a shiny stainless steel shaft will be visible. with the bottom of the stack: a nylon spacer, the die with the metal taped to it (the metal should be on top, or visible to your eye as you look down at the stack), a sheet of urethane measuring 95-durometer points, and another nylon spacer. The die needs to be centered in the stack and centered in the press. 16 The platens on the press frame were raised to the point at which the stacked sandwich fits loosely between them. Note that the urethane is on top of the sterling silver sheet to be formed. 19 This photo shows the first pressing compared to a flat sheet. The first pressing is important because it establishes the form. For the first pressing of this piece, the pressure was taken to 7,000 pounds per square inch, or psi, (4.8 Pa) with 95-durometer urethane. 132 The Penland Book of Jewelry 13 The etched pattern must be lined up with the cutout silhouette of the die. 14 I secured the metal sheet to the die with masking 17 The metal was beginning to be pushed into the negative area of the die (although in this photo, the urethane is not deformed). Notice the extended ram on the bottle jack. The Penland Book of Jewelry 133
Any other comments that are germane 26 For a fully 20 First and second pressings are compared in this photo. After the first or second pressing, I switch from 95-durometer-point urethane to 80-durometerpoint urethane, which is much softer and moves the metal much farther, much faster. A lower psi (Pa) is used with the 80-durometer-point urethane. 21 Here are die forms in two different stages of forming. 22 Because each die is a unique forming experience, I keep a record of the following variables: 23 This is the first die I made for this project. I decided that the neck on this form was too skinny, so I made a second die with design modifications. 24 These are fully formed copper maquettes of the second, modified die. The process is time intensive, so for a deep form, I usually press two of each side. This way if one blows out, I don t have to start 25 Here is a series of blowouts. It takes time to figure out what a die can handle. This is one reason for beginning with copper maquettes. With time and experience, you can estimate to some extent how much pressure a form can handle, although there are always surprises. Throughout the forming process, I make notations directly on the die form to indicate what stage it is in. When I have four to eight pieces in rotation and other things are happening in the studio, it is easy to lose track of this information. In the photo for example, the A with a circle around it means that the piece has been annealed and is ready for another pressing. The #2 marking means it is a pressing from the second die. The markings A1, A2, and A3 indicate which side of the die is being formed and which blank it is. I record a log for each piece A1, A2, A3, etc. in order to understand what the metal can handle in the die. three-dimensional form, the two halves must fit together perfectly. I make most of the preparations for this fit along the way by using a computergenerated mirror image, by using brass faceplates, and by carefully cutting and filing the brass faceplates. I chase the edges of the die form flat before cutting out the forms (see photo). Ninety-five percent of the flatness should be achieved with chasing because chasing disperses material, while filing and sanding removes material. The goal is to get this edge nice and flat. 27 I used a sanding stick to help determine how flat the edge was around the form. The type of metal The gauge of the metal The psi (Pa) achieved for each pressing The starting height and ending height for each pressing The type of urethane used again. I keep notes directly on the face of the die form. The examples shown are the first form I pressed for the B side of the die (left) and the fourth form I pressed for the A side (right). These forms are finished, so they are marked Do Not Anneal. Their height, 17.5 mm, is also marked. 28 There was an area on the bottom of the form that was not as flat as the rest of the form, so additional chasing was required. 134 The Penland Book of Jewelry The Penland Book of Jewelry 135
29 It is difficult to determine if the entire edge of the die form is flat when it is still attached to the whole sheet. An intermediary step is to cut a flange around the die form. The flange that I cut was approximately 4 mm wide. I used dividers to scribe a consistent flange around the form. Throughout the entire process, I keep all of the forms moving forward in tandem to achieve the most accuracy. It is important that the die form be fully prepped before removing the entire flange. 31 I used a permanent marking pen as layout fluid to cover the edge I needed to flatten. 32 When the form was moved across a sanding 34 I cut off the flange very close to the die form. 35 The edge of the die form was filed flush. Care 37 I used a pen to fill in the ornamental pattern so I could see it more easily for drilling and sawing. 38 Prior to piercing the pattern on each of the die 30 These are the chasing tools that worked best for me in this scenario. board, some of the marker ink was removed, making it clear which areas were flat and which were not. 33 Low spots were revealed when the marker ink was not removed. When there are low spots, I re-chase those areas and recheck them using the same marker and sanding board method. must be taken not to deform the die form through torquing and twisting. To prevent this, I held the form in my hand and braced my hand against the bench pin. 36 The back side was filed flat to remove the burrs and sanded to reveal the thickness of the metal. form halves, I gently but firmly pressed the tip of a sharp scribe into the surface of the metal to create a dimple where the drill bit can seat. 39 I held the die form at whatever angle was necessary to control drilling the hole. After the hole was drilled, I straightened the hole with the rotating drill bit. This enabled the saw blade to fit easily and comfortably into the hole at whatever angle was required for sawing. 40 Here, I began to pierce the pattern. 136 The Penland Book of Jewelry The Penland Book of Jewelry 137
41 Both halves of the form are pierced in this photo. After sawing, the pierced areas must be 42 To solder the two halves together, the inside edge of one half was tinned with solder. 43 Here, the two die-formed and pierced halves are filed. ready for soldering. 138 The Penland Book of Jewelry