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in Liquid Rubber & Plastic for Moldmaking & Casting

No. 23 • Spring 1998


	Decor & Figurines

Sculptor "Hams It Up" with First Venture into Moldmaking

BY ANGUS MACAULAY

     After 30 years as a professional sculptor, Vladimir Salamun took his first steps into the world of moldmaking by bringing Mother Nature together with cutting edge materials and technology. He decided to employ Polytek^® mold rubbers to cast a 20-inch-long sculpture of a striding sow.
     A nationally recognized sculptor with a keen knowledge of tools and materials, Salamun was still a novice moldmaker. His first attempt at casting a rubber mold was an aggressive one that would require several consultations with Polytek^®'s expert technical team.
     In choosing the materials and method to use, the sculptor faced two main challenges. First, and most obvious, was how to deal with a model standing on four legs. On the advice of Polytek^®'s specialists, Salamun decided a plaster shell and poured blanket mold was the best choice for casting a model of his pig. A flexible liner of Poly 74-30 made it possible to release the legs with a single seam on the inside of each limb.
     The second challenge was even more significant. The model was made of a plasticene clay of unknown origin. Over the years, the clay could have come in contact with any number of foreign materials. Poly 74-30 is seldom affected by plasticene models, but it has happened. The safest route is usually the best route in moldmaking, so the model was sealed with a coat of shellac.

Vladimir Salamun removes the mold from a casting of a striding sow. Salamun chose an aggressive project for his first moldmaking endeavor. His talent and skill, and Polytek^®'s liquid rubbers, made the project a success.

    Next, Salamun addressed the construction of the plaster shell. As a general rule, the shell should be kept simple, with as few pieces as possible. It was decided that the shell would be made in three main pieces. As the clay blanket was built over the model, it became apparent to Vladimir that three smaller "plugs" could be used to form a thinner blanket of rubber around the legs. This would maximize the flexibility of the rubber in these critical areas. Although this made a total of six pieces, keys in the shell's broad flanges made assembly easy and precise.
     The clay used for the clay blanket was removed from the model and weighed to estimate the amount of Poly 74-30 needed for the mold. With most clays, 0.7 times the weight of the clay blanket approximates the total weight of Poly 74-30 needed. Pol-Ease^® 2300 was then sprayed over the entire model sur-face and inside the sealed mold shell to prevent the Poly 74-30 from sticking to these surfaces. The plaster shell was then reassembled around the model. The seams were sealed with plasticene, and the properly weighed and mixed Poly 74-30 was poured.
     After 24 hours, the shell was removed, exposing the cured Poly 74-30. A mold key knife was used to make the primary cut lengthwise around the pig. In areas that were more difficult to reach or maneuver, a knife or scalpel was used. The result was a two-piece rubber mold that fit together in a tongue and groove fashion, assuring proper alignment.
     The Polytek^® technical team members were so impressed with the success of this first-time moldmaker that they invited Vladimir to make his first casting with the aid of Polytek^®'s rotational casting machine. The results were excellent: a near-perfect Poly 1512 casting with minimal cleanup required at the seams. Vladimir now has a mold suitable for casting plaster, bonded bronze, wax, and many other materials.
     "Vladimir's attention to detail, teamed with a versatile mold rubber like Poly 74-30, is a tough combination to beat," said Angus Macaulay, Polytek^®'s applications specialist.

Moldmaking Scenes, Fall '97

Angus Macaulay discusses technique with Mark Boyle of London, England, and Thomas Zaremba of Center Line, MI, at a recent seminar.


	Local sculptor Virginia Abbott Connor displays her cold-cast bronze bas relief of the Southern Belle steam engine, made of Polytek^® Poly 15-6 with bronze powder in a Poly 74-30 rubber mold.

Ashley Gray of Myersville, MD, displays his sculpture entitled "Spirit Carries On".

Scott Verhagan of New York reproduced an extremely difficult piece utilizing a soft, flexible inner core made with PlatSil^® 71-10. Note that the core is hollow to allow it to be collapsed for removal from the tight inside of the piece. The outside mold was Poly 74-30 polyurethane elastomer. It was cut to open with one seam and was stiff enough to hold the core in the exact desired position. The casting was done in both plaster and Poly 15-5X fast-setting liquid urethane casting plastic.

Patricia Springmeyer of Minden, NV, works with Joe Lawrence of Polytek^® to make a brush-on mold of her standing nude sculpture using Poly 74-30 thickened with Cab-O-Sil^®. They are shown cutting the mold open along the parting line.

Bernard Kilbourn of Blairstown, NJ, made a poured block mold of his wood model with PlatSil^® 71-10 and a duplicate casting of fast-setting Poly 15-5X, all in a couple of hours.


	Wade Ford of Durham, NC, holds a plastic mold shell of Polygel^® Plastic 75 with a poured blanket mold of fast-setting PlatSil^® 71-10. The original sculpture was plasticene. The first casting in plaster is being held by Joe Lawrence of Polytek^®.

Manhattan Circumnavigated after Seminar




After a recent Moldmaking Seminar/Workshop at Polytek^®, Lisa Vaughn and Sean Atteberry (both above) of United Design, Noble, OK, and Mark Boyle (left) of London, England, circumnavigated Manhattan with Bob LeCompte (far left) of Polytek^®, enjoying spectacular views of the Statue of Liberty and the Manhattan skyline.

1998 Seminar/Workshop Schedule

April 16 & 17 and October 8 & 9 are the dates for the two Seminar/Workshops scheduled for 1998. The two-day sessions will be held at Polytek®'s well-equipped 5,000-square-foot moldmaking and casting demonstration and shop area in the Easton, PA, facility. Each session can accommodate up to 30 people. A complete review of all Polytek® materials and methods of use is followed by hands-on moldmaking and casting. Each two-day attendee does their own project with the assistance of Polytek® technicians and chemists. In addition to seeing many different materials in use, the objective is for each attendee to make their own mold and casting. The fee for both days, including all materials, is $300 and includes a manual and a video of a portion of a previous session.
Advance registration is required. For more information, please request our Seminar/Workshop letter.

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