Developments

in Liquid Rubber & Plastic for Moldmaking & Casting
line

No. 25 • Spring/ Summer 1999

 

Decor & Figurines

Everything You Need to Cast Foam Parts
Parts Are Demolded in 10 Minutes

PolyFoam™ R-8
Makes Great Molded Ornament

THE FOAM: PolyFoam™ R-8 is sold in pails. It is an easy-to-use, 1:1-mix, room-temperature-setting liquid that expands within a few minutes of mixing to an 8-pound-per- cubic-foot density, rigid, wood-like foam, if allowed to free rise. For molded parts like the plaque shown, PolyFoam™ R-8 is usually compressed to about a 13-pound-per-cubic-foot density by clamping a lid on the mold. In the photo the lid is simply a laminate-coated 3/4 inch particle board with vent holes drilled to allow air above the foam to escape. The Turbo Mixer is used on a drill to quickly and thoroughly mix the PolyFoam™.
THE MOLD: PlatSil® 73-45 RTV Silicone Mold Rubber is used for the mold. It is easily made by mixing the liquid rubber, pouring over a properly prepared model within the mother mold, and allowing to cure overnight at room temperature.
THE MOTHER MOLD: Poly 15-3X Liquid Plastic was used to pour a permanent mold shell (mother mold) over the original model. A space was created between the model and the shell by coating the model with a layer of Poly Plasticene. When the shell was cured, the plasticene was removed and the PlatSil® rubber was poured into the space to create the mold.
THE RELEASE AGENT: Pol-Ease® PF Release is sprayed lightly into the mold and allowed to dry for a few minutes. It allows the Barrier PF to leave the mold cleanly on the foam part.
THE BARRIER COAT: Barrier PF is  like a paint that is sprayed into the release- coated mold and allowed to dry. The Barrier PF protects the mold and comes out bonded to the surface of the foam part, acting as a primer so the part can be easily painted or stained.

How To Get Started
Enough material for 32 parts
(each 2 inches x 4 inches x 7 inches) for less than $150

It's easy to make a small trial mold and castings of PolyFoam™.
     Take advantage of the low Trial Unit prices listed on page 8. Remember, freight is free for accessories ordered with a Trial Unit, up to the value of the Trial Unit.
     You may need Poly Plasticene (5 lb.) to sculpt an original shape or make a blanket over your original to form the strong shell. Covering the plasticene with plastic wrap will keep the plasticene from sticking to the plastic. Pour a strong shell of Poly 15-3X (5 lb.) or other Poly Plastics. Pour PlatSil® 73-45 (1 or 2 lb.) into the space created between the model and the shell to make the mold. Coat the cured mold with Pol-Ease® PF (2 lb.) and then Barrier Coat PF (2 lb.). After drying the barrier for a few minutes, mix with a Turbo Mixer an amount of PolyFoam™ R-8 to pack it to density of 16 pounds per cubic foot or 108 cubic inches per pound (0.056 g/cc). Immediately pour it into the mold and clamp the release-coated lid in place. Ten minutes later, demold your part. A 16-lb Unit of PolyFoam™ R-8 will produce one cubic foot (1728 cubic inches) of packed foam castings.

                      SPECIAL OFFER

Request your FREE DEVELOPMENTS™ moldmaking & casting newsletter, including an order form for Trial Units at special low prices.
                                   OR
Send $24 for a 1/2-gallon Trial Unit sent to you with free freight anywhere in the contiguous U.S. Request our 60-page Manual & Catalog ($10 value) sent free with any order. Specify Poly 74-30 Liquid Rubber or EasyFlo™ 60 Liquid Plastic. Order both for $44 and receive a FREE can of Release Agent and the FREE Manual & Catalog.

Final touches of exterior paint are applied to the refurbished Poly Bird.

The life-size blue heron made of Poly 15-6 liquid plastic was outdoors at the edge of a New Jersey pond for over 10 years, subjected to all the wear of summer and winter weather, with accompanying ice skaters and hockey players. The paint was getting a little thin and the steel legs a little rusty, so we brought him back to our shop for a touch-up. A light sanding and a new coat of Krylon primer, with subsequent coats of exterior-grade latex and oil paints, were all that was required to make him look as good as new.
The original mold of Poly 74-30 Poly Urethane Liquid Rubber and the mold shell made with thickened Poly 15-6 Liquid Plastic, the same material used to make the Poly Bird, are also still in perfect condition 10 years later.
Back in the water again, Poly Bird is ready for the first decade of the new millennium.

Moldmaking Scenes, Fall '98

A two-piece mold of Poly 74-30 is poured by Linda Kays (above and at right) of Gnombodies & Somebodies of Norwich, NY, as Angus makes sure all is well. Linda went home with a mold and several castings of the figure she brought as her seminar project.

Sculptor and jeweler Sandra Lira is happy with the results of her cut one-piece mold of PlatSil® 71-20 and mold shell and casting of Easy-Flow™ 60, all 1:1 mix and fast-setting. This type of project can be easily done in less than one day. Sandra's project was a complex winged sculpture on a pedestal. Perfect results were obtained with a carefully thought-out plan for the methods and materials she selected—soft rubber and tough casting resin.

David Eldreth poured Easy Flow™ 60 into a mold of TinSil® 70-25 to obtain a fast-setting, nearly unbreakable reproduction of his bas-relief original.

1999 Seminar/Workshop Schedule

     June 10 & 11 and October 7 & 8 are the dates for the next two scheduled Seminar/Workshops. 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 & Catalog 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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