Pattern resin is changed from a liquid to a solid when exposed to ultraviolet light. A high contrast negative is used as a mask. During exposure, the resin under the clear areas of the negative is exposed, and the resin hardens.

The black areas of the negative hold back the light. The resin under the black is not hardened and is still liquid, so when the pattern is scrubbed out, a raised design is left.

Three different ways are shown to make a negative. The printing industry uses high contrast negatives made on a process camera.

Another approach is to use an inkjet printer. However, most inkjets do not have enough density, so the inkjet print needs to be made into a transparency on a toner-based copier.

The quickest and easiest negatives are made with transparencies for laser printers on a 600 dpi laser printer. All three methods of negative making are shown in the video.

To show how pattern resin relates to lost wax and sand casting, three different designs are created on the computer, and taken through the steps for both sand casting and the lost wax or investment casting process.

In the first segment of the video, the lettering and design is attached to a pattern for sand casting. The pattern is cut from aluminum bar stock, drilled, tapped and a taper machined on a metal lathe. The finished pattern is rammed up in petrobond sand and a metal casting is made.

The second segment of the video shows a two sided design, starting with a scanning part of the design and adding lettering on a computer. The design is printed as a negative on an inkjet printer, and a negative transparency made on a copier.

A striplight is assembled for use as an inexpensive way to expose the pattern resin using blacklight fluorescent bulbs.


The pattern resin is poured directly on the negatives, exposed to blacklight and as the photo to the right shows the scrub out is done in ordinary tap water.

The third segment of the video shows a negative made on a laser printer only exposed through one side to create a pierced design for a pendant.

A vulcanizer is used to make a mold. Close-up photography shows the mold being cut. From this mold multiple waxes can be injected.

The wax model is put on a sprue. The investment process is shown from mixing, debubbling, steam dewaxing and burnout.

Two casting methods are shown. Vacuum assist and spin casting, sometimes called centrifugal casting. Sterling silver is cast by vacuum assist and brass is spin cast. CONTINUED NEXT PAGE