USG - united states gypsum - plaster and hydrocal cement

Page 1 - Home - Overview

The use of plaster for reproduction of art objects is over 5,000 years old. Plaster objects have been discovered in Egyptian burial vaults. Michaelangelo constructed full-size plaster models of his statues before rendering them in metal. Plaster moldings, cornices and interior trims were once very popular in Europe, as well as in the United States. From ancient days to modern times, plaster has occupied an every-changing role in decorative and creative life. Plaster crafting was treated as a "secret art" handed down from artisan to artisan. This is no longer true. The plaster craft industry is one of the fastest growing segments in the arts and crafts field.

Books for Art & Industry

Plaster Master Industries Home

United States Gypsum Company has played a major role in the growth of this industry with the development of the finest industrial plasters and gypsum cements. U.S. Gypsum has supported, and will continue to support, the industry with: training programs, product literature, skilled sales staff, new and improved products and techniques and Company assistance in trade association activities, seminars and meetings. The purpose of this website is to provide a working knowledge for more effective use of industrial plasters and gypsum cements, as a means of improving results in plaster crafting.

The United States Gypsum Company offers a complete line of industrial plasters to meet specific requirements, whatever the need. With extensive research facilities and years of specialized experience, U.S. Gypsum has developed plasters ideally suited for a broad scope of special requirements.

usglion2.gif (6862 bytes)

USG® Moulding Plaster

This general-purpose plaster produces casts of nominal strength and hardness, faithfully reproduces the most intricate detail. Casts made of moulding plaster are porous and must be carefully sealed before decorating

USG White Art Plaster

Similar in working properties to moulding plaster, White Art Plaster contains a surface hardening agent, which minimizes paint absorption when the dried cast is finished. When mixed at recommended 70 consistency (see consistency info), USG white art plaster gives excellent detail, provides a harder surface and has lower paint absorption than moulding plaster.

Typical art object cast in gypsum plaster

USG No. 1 Casting Plaster

The industry standard for figurines, plaques and lamp bases. Special additives maintain smooth-working qualities and upon drying, result in a hard working surface with reduced paint absorption and a degree of chip-resistance without sacrificing. The best and most uniform surfaces are developed by first drying the cast in a circulating warm-air oven not over 120ºF. When mixed at the recommended consistency, 65 parts of water to 100 parts of plaster, No. 1 Casting Plaster gives better over-all results than White Art Plaster.

Industrial Plaster PC

A special plaster blended with polymer and synthetic fibers for producing solid or slush-cast products. It provides better chip resistance and impact strength in cast items than either USG White Art Plaster, USG No. 1 Casting Plaster or HYDROCAL White Gypsum Cement. Provides greater green strength than USG White ART Plaster or USG No. 1 Casting Plaster. Industrial Plaster PC is recommended for casting whenever superior chip resistance is desired. These plasters are used for making items such as three-dimensional plaques, figurines, lamp bases and even simulated-stone furniture. They also are used by many shops for shells to support latex-type molds. Superior strength permits thinner castings weighing 25 to 35% less.

Industrial Plaster PC-1

Formulated for manufacturing decorative brick, stone and other deeply colored cast objects, this product permits blending large quantities of pigment needed to simulate natural materials. Industrial Plaster PC-1 contains a highly efficient dispersant that improves and provides deeper, richer, more uniformly colored casts. The washed-out milky surface discoloration caused by bleeding white plaster color during drying is virtually eliminated. The dispersant reduces the amount of high-cost pigment that's needed to produce the same color casts. Also, cast products retain their strength because the mix is not diluted with low-strength pigments. For example, up to 50% dry impact strength may be lost at high pigment levels. Because of a slight brownish cast in the slurry, this plaster is not recommended for casting "white" objects.

U.S. Gypsum offers a full line of gypsum cements that possess much greater strength and hardness than standard industrial plasters. Gypsum cements require less water for mixing and produce casts that are less porous, easier to paint, heavier and more durable. Since gypsum cements generate more heat upon setting than standard industrial plasters, they should not be used with glue molds. Instead, molds of latex, hot melt, polysulfide rubber, silicone, or urethane rubber are recommended.

usgcement1gif.gif (7149 bytes)

Hydrocal White Gypsum Cement

Hydrocal White Gypsum Cement offers a gradual setting time and a long period of plasticity. Recommended for both solid and hollow casting of lamp bases and figurines. Especially designed for thin sections, which require high green strength to minimize breakage during removal from an intricate latex mold. HYDROCAL White Gypsum Cement should be mixed at 45 consistency which gives it moderate carvability.

usgcement3gif.gif (7649 bytes)

HYDRO-STONE Gypsum Cement

One of the hardest and strongest of all gypsum cements. When mixed properly at 32 consistency, which is easily poured into a mold. Although not suitable for carving or slush casting, HYDRO-STONE Gypsum Cement is recommended for producing high-quality novelty and statuary castings requiring extremely hard surfaces. Best results are obtained when this product is mechanically mixed.

Among the many articles that can be cast in industrial plasters and super-strength HYDROCAL gypsum cements are statuary and other art objects, lamp bases, advertising displays, premium ware, molds, novelties, dioramas and simulations. The casting process involves: proper proportioning and mixing of plaster with water; pouring (or otherwise placing) the mixture in molds; allowing it to set up hard; trimming and smoothing; drying, and finally, decorating the casts.

The four requirements for producing attractive, salable and durable plaster castings are:

usgdog3.gif (5895 bytes)

Good design - An esthetically pleasing, but practical design or model should have rounded edges and corners, adequate thickness, proper surface, and be of a shape that can be easily cast.

Good material - The proper plaster or gypsum cement should be selected for the intended use and handled correctly.

Good molds - Since casts will faithfully reproduce the model only if good molds are used, the mold must have accurate reproduction of detail, proper surface and correct design. In addition, it should be easy to work with and have sufficiently long life to produce the casts desired.

Good finish - A durable finish of desired color and texture must be applied properly to the prepared casting.

Esthetically pleasing with rounded edges, this plaster cast is also easy to work with

These essentials should be carefully provided before actual production is undertaken.

When you're dealing with a cast of thousands, the performance has got to be good. That's why TUF STONE™ Gypsum Cement, TUF CAL™ Plaster, and FAST CAST™ Exterior Gypsum Cement were created. These specialty products from United States Gypsum Company offer greater resilience and chip resistance than other casting products. This means fewer returns due to breakage, less waste, and increased productivity for you. Plus, these high quality, U.S. gypsum materials reproduce fine detail, are less expensive than resin-based products, contain no toxic compounds, and require no special solvent for cleaning. The result is a great performance no matter what size your cast.

United States Gypsum Cement

U.S. Gypsum Plaster

USG Cement

TUF STONE™ Gypsum Cement

Designed for solid casting, TUF STONE Gypsum Cement is a new, polymer modified, fibered material specifically manufactured for giftware applications. This product's unique formulation provides three times the impact resistance of standard materials, greater chip resistance, and much higher resilience. Plus, TUF STONE gypsum cement is easy to mix and is compatible with many color pigments. Best of all, it's less expensive than resin-based products. Available in 50-pound and 100-pound bags.

TUF CAL™ Plaster

For hollow casting, TUF CAL Plaster is the artist's choice. This polymer modified, fibered plaster provides high early strength and can be used for interior applications including lamp bases and hollow statuary. In addition to its excellent resilience and chip resistance, TUF CAL plaster is easy to use and since it dries at 110ºF, you don't need a kiln. For best results, a mechanical mixer should be used to ensure proper polymer/fiber distribution in the mix. Available in 50-pound and 100-pound bags.

FAST CAST™ Exterior Gypsum Cement

As its name implies, FAST CAST Exterior Gypsum Cement is a rapid setting cementitious material that is mixed with sand for free standing, exterior casting and decorative exterior figurines. (It is not, however, designed for water-holding products such as bird baths or planters, nor is it suitable for structural or non-structural exterior architectural applications.) FAST CAST Exterior gypsum cement produces strong, hard casts that can be demolded in as little as one hour after set, increasing productivity 300% over conventional cements. Available in 50-pound and 100-pound bags.

Plaster Master Supply
4308 Shankweiler Rd. Orefield, PA 18069
Phone (610) 391-9277 · Fax (610) 391-0340