{"title":"Plasters","description":"\u003ch3\u003ePLASTERS\u003c\/h3\u003e\n\u003cp\u003eThis page contains plasters and casting materials from Georgia-Pacific and US Gypsum (USG).\u003c\/p\u003e\n\u003cp\u003eLooking for USG #1 Pottery Plaster? USG no longer makes it. Our pottery plaster is now \u003ca href=\"\/products\/georgia-pacific-k-59-plaster-50-lb\"\u003eGeorgia-Pacific K-59 Pottery Plaster\u003c\/a\u003e, for slip-casting molds, press molds and wedging table tops.\u003c\/p\u003e\n\u003cp\u003eBulk discounts are available for US Gypsum products.\u003c\/p\u003e\n\u003cdiv\u003e\n\u003cp\u003ePlease call us toll-free at \u003ca href=\"tel:1-888-774-2529\"\u003e1-888-774-2529\u003c\/a\u003e to order large quantities of the items on this page. Thank you. \u003ca href=\"#abz_below_richtxt_id\" style=\"background-color: initial;\"\u003eLearn more\u003cbr\u003e\u003cbr\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e","products":[{"product_id":"usg-super-fine-casting-plaster-50-lbs-rmsfcp","title":"USG Super-Fine Casting Plaster","description":"\u003cdiv class=\"rm-testing-statement\" style=\"border:2px solid #8a5a00;border-radius:6px;padding:12px 16px;margin:16px 0;background:#fdf6e3;\"\u003e\u003cp style=\"margin:0;\"\u003e\u003cstrong\u003eYou must test before you use it, at any scale.\u003c\/strong\u003e Raw materials, mined or man-made, are not consistent. Setting time, strength, expansion and absorption can change from one bag to the next and from one supplier to another, even when the name on the bag stays the same. Before you pour a mold or casting of any size, mix a small test batch with your own water and mixing method, let it set, and check the results.\u003c\/p\u003e\u003c\/div\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003ch2 class=\"abz-seo-product\"\u003eUSG Super-Fine Casting Plaster 50 Lbs.\u003c\/h2\u003e\n General use plaster of Paris","brand":"USG","offers":[{"title":"50 Pounds","offer_id":45105282253122,"sku":"RMSFCP50","price":31.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/usg-superfine-casting_497458bd-fb84-4817-9132-2305228d05b5.jpg?v=1791876105"},{"product_id":"u-s-gypsum-duramold-50-lbs-bag-rmduramo","title":"USG Duramold","description":"\u003cdiv class=\"rm-testing-statement\" style=\"border:2px solid #8a5a00;border-radius:6px;padding:12px 16px;margin:16px 0;background:#fdf6e3;\"\u003e\u003cp style=\"margin:0;\"\u003e\u003cstrong\u003eYou must test before you use it, at any scale.\u003c\/strong\u003e Raw materials, mined or man-made, are not consistent. Setting time, strength, expansion and absorption can change from one bag to the next and from one supplier to another, even when the name on the bag stays the same. Before you pour a mold or casting of any size, mix a small test batch with your own water and mixing method, let it set, and check the results.\u003c\/p\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12pt; font-weight: bold;\"\u003eU.S. Gypsum DURAMOLD™ Pottery Plaster 50 lbs. Bag.\u003c\/span\u003e\u003cbr\u003eDURAMOLD was created to meet the demanding needs of the slip casting industry. Compared to #1 POTTERY PLASTER, DURAMOLD features longer mold life and higher wet and dry compressive strength.\u003c\/p\u003e\n\u003cp\u003e– Used at a lower consistency than conventional pottery plasters.\u003cbr\u003e– High wet strength for less breakage in process.\u003cbr\u003e– Ideal for jiggering applications.\u003cbr\u003e– Extended mold life.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eTechnical Properties \u003c\/span\u003e\u003cspan style=\"font-weight: bold;\"\u003eEnglish Metric\u003c\/span\u003e\u003cbr\u003eUse Consistency (parts of water by weight per 100 parts plaster ) 62 62\u003cbr\u003e1 Hr. Compressive Strength 1,300 psi 8.8 MN\/m2\u003cbr\u003eDry Compressive Strength 2,900 psi 19.7 MN\/m2\u003cbr\u003eTotal Absorption Capacity 30% 30%\u003cbr\u003eMaximum Setting Expansion 0.220% 0.220%\u003cbr\u003eDensity Wet 102.5 lb\/ft3 1.64 g\/cm3\u003cbr\u003eDry 75.0 lb\/ft3 1.20 g\/cm3\u003cbr\u003eSet Time (Machine Mix)* 14-24 min. 14-24 min.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eGeneral Directions and Guidelines\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003ePreparing the Mix\u003c\/span\u003e\u003cbr\u003eUse potable water at temperatures between 70° and 100° F (21° and 38° C). Since variations in slurry (the plaster and water mixture) temperature produce variations in setting time, it is important to keep both the plaster and water in a stable temperature environment prior to use. The higher the temperature of the water, the shorter the set time.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eSoaking\u003c\/span\u003e \u003cbr\u003eSift or strew the plaster into water slowly and evenly. Do not drop handfuls of plaster directly into the water. Allow soaking for\u003cbr\u003e1-2 minutes. The plaster should be fully dispersed in the water prior to mixing. Small batches require less soaking than large\u003cbr\u003ebatches. See bulletin IG503 for specific soaking instructions.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eMixing \u003c\/span\u003e\u003cbr\u003eMixing the plaster slurry is one of the most important steps in producing plaster molds with maximum strength, absorption,\u003cbr\u003ehardness, and other important properties.\u003cbr\u003eMechanically mixed plasters develop uniform molds with optimal strengths. Plasters can be mechanically mixed through\u003cbr\u003eboth batch and continuous processes. Proper blade and bucket dimensions are important for obtaining the best batch mix\u003cbr\u003e(see IG503 for details).\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003ePouring \u003c\/span\u003e\u003cbr\u003eTo prevent air entrainment and provide a uniform, smooth surface, careful pouring of the plaster slurry is necessary. Agitation of the filled case mold is a further step used to prevent air at or near the mold surface. Whenever possible, the plaster slurry\u003cbr\u003eshould be poured carefully in the deepest area so the slurry flows evenly across the surface of the case mold.\u003cbr\u003ePouring a large amount of slurry directly on the face of the case mold may result in slight densification of the plaster mold\u003cbr\u003eat the point where it strikes the surface of the case. This produces a hard spot, giving uneven absorption.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eDrying\u003c\/span\u003e \u003cbr\u003eAll pottery molds should be dried as quickly as is safely possible after manufacture so that maximum physical properties can\u003cbr\u003edevelop. Dry to a constant weight.\u003cbr\u003eThe best drying rooms or ovens provide (1) uniform and rapid circulation (minimum of 15-30 fps) of air with no “dead spots”\u003cbr\u003ehaving little or no air movement, (2) equal temperatures throughout the entire area, and (3) provisions for exhausting a portion\u003cbr\u003eof the air while replacing it with fresh air. High humidity surrounding the drying room or oven inhibits the efficiency of the drying\u003cbr\u003ebecause the air pulled into the room is incapable of picking up much moisture from the molds.\u003cbr\u003eThe maximum temperature at which plaster molds are safe from calcination is 120° F (49° C). With substantial free water in\u003cbr\u003ethe mold, higher drying temperatures can be used without difficulty. As drying progresses, the temperature must be reduced to\u003cbr\u003eprevent calcination. The safe drying zone is in the shaded area of graph (below, right). Before removing molds from the dryer,\u003cbr\u003ethe temperature should approach that of the area around the dryer to prevent thermal shock.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eStorage\u003c\/span\u003e\u003cbr\u003eKeep in a dry, stable environment indoors. Do not stack more than 2 pallets high. Keep from drafts. Rotate stock.\u003cbr\u003e\u003c\/p\u003e","brand":"USG","offers":[{"title":"50 Pounds","offer_id":45113708314946,"sku":"RMDURAMO","price":34.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/RMDURAMO-2_18c0f106-c4bd-4742-91f0-1b176b88c36c.jpg?v=1791876656"},{"product_id":"u-s-gypsum-hydroperm-50-lbs-bag-rmhydrop50","title":"USG Hydroperm Metal Casting Plaster","description":"\u003cdiv class=\"rm-testing-statement\" style=\"border:2px solid #8a5a00;border-radius:6px;padding:12px 16px;margin:16px 0;background:#fdf6e3;\"\u003e\u003cp style=\"margin:0;\"\u003e\u003cstrong\u003eYou must test before you use it, at any scale.\u003c\/strong\u003e Raw materials, mined or man-made, are not consistent. Setting time, strength, expansion and absorption can change from one bag to the next and from one supplier to another, even when the name on the bag stays the same. Before you pour a mold or casting of any size, mix a small test batch with your own water and mixing method, let it set, and check the results.\u003c\/p\u003e\u003c\/div\u003e\n\u003cspan\u003e\u003c\/span\u003e\n\u003ch2 class=\"abz-seo-product\"\u003eU.S. Gypsum HYDROPERM 50 lbs. Bag\u003c\/h2\u003e\n\u003cp\u003eHYDROPERM gypsum plaster is a specially formulated product incorporating an air entraining agent to provide permeability. For producing permeable plaster molds for precision casting of many nonferrous metals and alloys. \u003cbr\u003e \u003cspan style=\"font-weight: bold;\"\u003eSealers and Parting Compounds \u003cbr\u003e\u003c\/span\u003eParting compounds (also called “separators” or “releasers”) are needed to prevent adhesion of plaster or gypsum cement to\u003cbr\u003epatterns or models. They also permit removal of plaster or gypsum cement from the surface of the pattern or model upon which\u003cbr\u003eit “sets up.” Porous model materials require sealing prior to application of the parting compound.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eHydroperm Gypsum Plaster Sealing\u003cbr\u003e\u003c\/b\u003eAll porous models, patterns and molds must be sealed before the parting agent is applied. Sealing is particularly essential for wood patterns to prevent dampness from causing the wood to swell, resulting in release difficulty. Gypsum cement plaster patterns also require sealing to prevent them from absorbing water from the plaster mix and causing the mix to adhere to the gypsum cement pattern. Patterns of metal, glass, plastic and other impervious materials normally do not require sealing.\u003cbr\u003eA quick-drying lacquer applied by brush or spray gun is an excellent sealer for wood, plaster and gypsum-cement patterns\u003cbr\u003eand master models. Two coats of lacquer provide more resistance to moisture than shellac. Correct procedure is to reduce lacquer with lacquer thinner so that the model or pattern readily absorbs the first coat. Apply second coat after first coat has thoroughly dried.Where a plaster or gypsum cement pattern is used, apply lacquer immediately after set.\u003cbr\u003eMahogany patterns or models require special treatment because gypsum cement plaster casts may adhere to undercuts caused by multiple pores or grain of the wood. A paste wood filler can be used to fill the grain of the wood, but should be reduced to a satisfactory brushing consistency with the recommended thinner. Apply a heavy coat of Hydroperm gypsum plaster and let it dull down; then wipe off excess by rubbing across the grain. After wood filler has set overnight, apply a coat of a clear acrylic sealer and allow to dry. Sand the pattern or model and apply several coats of a clear lacquer.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eSeparators Satisfactory separation agents must provide the following functions:\u003c\/span\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003ePrevent adhesion to the gypsum cement plaster cast.\u003c\/li\u003e\n\u003cli\u003eProtect and lubricate pattern surface.\u003c\/li\u003e\n\u003cli\u003eSpread easily and uniformly in a thin, continuous insoluble film.\u003c\/li\u003e\n\u003cli\u003eDo not react destructively with the plaster or gypsum cement surface, or with the pattern.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eSome of the most common and widely used separators are as follows:\u003cbr\u003eSoaps—A number of special “potter’s” soaps are available for use as parting compounds. “Green soap” (a liquid) is an effective\u003cbr\u003eparting compound when cut 10 to 1 with distilled water. Apply parting soap with a sponge and work into plaster surface. Several\u003cbr\u003ecoats may be required on a new mold. Remove excess soap with a clean wet sponge before pouring mold.\u003cbr\u003eStearic Acid and Kerosene (Stearine)—Formula: 1\/4 lb. stearic acid shaved to flakes; 1 pt. kerosene. Melt stearic acid by warming: remove from heat source and add kerosene with constant stirring until a uniform mixture is obtained. Apply to pattern with a soft brush, preferably camel’s hair or sable hair. If brush marks show, thin mixture with more kerosene or by warming. This separator is one of the most widely used of all parting compounds and is particularly recommended for use with glue molds.\u003cbr\u003ePetroleum Jelly (Vaseline)—Formula: 1 part petroleum jelly; 2 parts kerosene. Use petroleum jelly if it is cut back with approximately two parts kerosene to one of jelly. Blend mixture by carefully heating and thoroughly stirring (Caution—Fire Hazard).\u003cbr\u003eApply as a thin coat and brush out thoroughly.\u003cbr\u003eFor special purposes, separators other than the above may be advantageous:\u003cbr\u003eLight Lubricating Oil—Use sparingly.\u003cbr\u003eLight Mineral Oil—Particularly effective as a fine fog spray on metal patterns. Must be thinned to be effective.\u003cbr\u003eOlive Oil—May be used if applied carefully while warm. Crisco and other similar hardened vegetable oils used as frying fats are\u003cbr\u003eparticularly recommended for use on lacquered wood.\u003cbr\u003ePowered Mica—Has been found useful when finely ground and added to most parting compounds. Satisfactory results have\u003cbr\u003ebeen obtained by adding 1\/4 to 1\/2 cup of the powdered mica to 1 qt. of parting compound solution.\u003cbr\u003eEPOXICAL® Mold Sealer Separator—Works well as a release agent of gypsum cements. Thin EPOXICAL Mold Sealer Separator as it comes in the can, using white gasoline or kerosene at a ratio of 1-to-1 by volume. Apply a generous coat to the pattern: allow to dry 2 to 3 minutes and then wipe off excess with a soft cloth.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eRemoval of Gypsum Cement Plaster Cast\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eWhen gypsum cement plaster has set on a properly sealed and separated surface, the model can be removed by one or more of the following methods:\u003c\/b\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eWedge evenly around surface with wedges or a sharp tool. \u003c\/li\u003e\n\u003cli\u003eUse compressed air gently to separate.\u003c\/li\u003e\n\u003cli\u003eSuspend piece so the weight of the mold, aided by light tapping, performs the separation.\u003c\/li\u003e\n\u003cli\u003eIn extreme cases, soak the cast and its pattern in warm water for a short time. Then apply one or more of the above techniques.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eCareful use of a compressed-air jet at a corner or convenient edge may be necessary to start release.\u003cbr\u003eCasts should always be completely set before removal is attempted. When molds or patterns of most flexible molding compounds are used to form the gypsum cement, no separator is necessary and removal of the set object is simplified. An exception to this is the glue or gelatin mold, on which a parting compound must be used.\u003cbr\u003eGeneral Recommendations Efflorescence (a crusty appearance on the model surface) may result if models, patterns or molds are made of HYDROCAL® Brand A-11, HYDROCAL Brand B-11, ULTRACAL® -30 or other gypsum cements or plasters and are dried slowly under conditions of moderate or high relative humidity.\u003c\/p\u003e\n\u003cp\u003ePatterns and models should be made hollow wherever possible to facilitate drying and minimize possibility of efflorescence.\u003cbr\u003eWhen aluminum and magnesium patterns and molds are used in conjunction with HYDROCAL Brand A-11, HYDROCAL Brand\u003cbr\u003eB-11 and HYDROSTONE® Cement, special care is necessary to prevent a metal-gypsum cement reaction. In these instances the\u003cbr\u003emetal must be carefully painted with a thin coat of cut shellac or clear lacquer and a separator needs to be applied. Failure to\u003cbr\u003eprevent contact between metal and gypsum cement will result in bubbles on the face of the HYDROCAL cast and a pitted surface\u003cbr\u003eon the metal.\u003cbr\u003e\u003c\/p\u003e","brand":"USG","offers":[{"title":"50 Pounds","offer_id":45113727091010,"sku":"RMHYDROP50","price":46.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/white-RMHYDROP50-2.jpg?v=1696879897"},{"product_id":"u-s-gypsum-hydrostone-50-lbs-bag-rmhydros50","title":"USG Hydrostone Gypsum Cement","description":"\u003cdiv class=\"rm-testing-statement\" style=\"border:2px solid #8a5a00;border-radius:6px;padding:12px 16px;margin:16px 0;background:#fdf6e3;\"\u003e\u003cp style=\"margin:0;\"\u003e\u003cstrong\u003eYou must test before you use it, at any scale.\u003c\/strong\u003e Raw materials, mined or man-made, are not consistent. Setting time, strength, expansion and absorption can change from one bag to the next and from one supplier to another, even when the name on the bag stays the same. Before you pour a mold or casting of any size, mix a small test batch with your own water and mixing method, let it set, and check the results.\u003c\/p\u003e\u003c\/div\u003e\n\u003ch2 class=\"abz-seo-product\"\u003eUSG Hydrostone Gypsum Cement 50 Lbs.50 lbs. Bag\u003c\/h2\u003e\n\u003cp\u003eUS Gypsum HYDRO-STONE is one of the hardest and strongest of all gypsum cements. When mixed properly, has a heavy, syrupy consistency ideal for pouring solid models or patterns. Recommended for stretch-press dies where extreme surface hardness is required. Slightly higher setting and expansion than ULTRACAL 30. This USG product is used for high quality art novelty and statuary castings.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eHYDRO-STONE®\u003cbr\u003eGypsum Cement\u003cbr\u003eProduct Data\u003cbr\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eHard and strong with high water absorption resistance.\u003c\/li\u003e\n\u003cli\u003eWorks well in plaster and most flexible moulding compounds.\u003c\/li\u003e\n\u003cli\u003eUsed in high-quality art novelty and statuary castings.\u003c\/li\u003e\n\u003cli\u003eExtremely fine detail duplication.\u003c\/li\u003e\n\u003cli\u003eLow viscosity slurry for filling multiple molds at one time.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eTechnical Properties \u003c\/span\u003e English Metric\u003cbr\u003eUse Consistency (parts of water by weight per 100 parts plaster) 32 32 \u003cbr\u003e1 Hr. Compressive Strength 4,000 psi 27.6 MN\/m2 \u003cbr\u003eDry Compressive Strength 10,000 psi 69.0 MN\/m2 \u003cbr\u003eMaximum Setting Expansion 0.240% 0.240% \u003cbr\u003eDensity Wet 119.0 lb\/ft3 1.91 g\/cm3 \u003cbr\u003eDry 108.0 lb\/ft3 1.73 g\/cm3 \u003cbr\u003eSet Time (Machine Mix)* 17-20 min. 17-20 min. \u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eGeneral Directions and Guidelines\u003c\/span\u003e \u003cbr\u003ePreparing the Mix Use potable water at temperatures between 70 and 100 °F (21 and 38 °C). Since variations in slurry (HYDRO-STONE® Gypsum Cement and water mixture) temperature produce variations in setting time, it is important to keep both HYDRO-STONE Gypsum Cement and water in a stable temperature environment prior to use.The higher the temperature of the slurry, the shorter the set time.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eMeasuring\u003c\/span\u003e Weigh both HYDRO-STONE Gypsum Cement and water at the recommended use consistency for each mix (see technical properties above). The water-to-HYDRO-STONE Gypsum Cement ratio is critical because it governs all physical properties of the final cast piece.\u003cbr\u003eSoaking Sift or strew HYDRO-STONE Gypsum Cement into water slowly and evenly. Do not drop handfuls of HYDRO-STONE Gypsum Cement directly into the water. Allow soaking for 1-2 minutes. HYDRO-STONE Gypsum Cement should be fully dispersed in the water prior to mixing. Small batches require less soaking than large batches. See bulletin IG503 for specific soaking instructions.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eMixing Properly\u003c\/span\u003e mixing HYDRO-STONE Gypsum Cement is the most important step to producing casts with maximum strength, hardness, and other important properties. Unlike other plasters and gypsum cements, HYDRO-STONE Gypsum Cement cannot be mixed by hand and must be mixed mechanically. Additionally, HYDRO-STONE Gypsum Cement can only be mixed by a batch process, not by a continuous process mixer. HYDRO-STONE Gypsum Cement properly via the mechanical\/batch process.Longer mixing times result in higher cast strength and shorter setting times.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003ePouring\u003c\/span\u003e To prevent air entrainment and provide a uniform, smooth surface, careful pouring of the slurry is necessary. Agitation of the filled mold is a further step used to prevent air at or near the surface of the cast piece. Whenever possible, the slurry should be poured carefully in the deepest area so the slurry flows evenly across the surface of the mold.\u003cbr\u003ePouring a large amount of slurry directly on the face of the mold may result in slight densification of the cast at the point where the slurry strikes the surface of the mold.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eDrying\u003c\/span\u003e All casts should be dried as quickly as is safely possible after manufacture so that maximum physical properties can develop. Dry to a constant weight.\u003cbr\u003eThe best drying rooms or ovens provide (1) uniform and rapid circulation (minimum of 15-30 fps) of air with no “dead spots” having little or no air movement, (2) equal temperatures throughout the entire area, and (3) provisions for exhausting a portion of the air while replacing it with fresh air. High humidity surrounding the drying room or oven inhibits the efficiency of the drying because the air pulled into the room is incapable of picking up much moisture from the cast pieces. The maximum temperature at which HYDRO-STONE Gypsum Cement casts are safe from calcination is 120 °F (49 °C). With substantial free water in the cast piece, higher drying temperatures can be used without difficulty. As drying progresses, the temperature must be reduced to prevent calcination. The safe drying zone is in the shaded area of graph (below, right). Before removing casts from the dryer, the temperature should approach that of the area around the dryer to prevent thermal shock.\u003cbr\u003e\u003c\/p\u003e","brand":"USG","offers":[{"title":"50 Pounds","offer_id":45113727254850,"sku":"RMHYDROS50","price":42.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/hydro-stone.jpg?v=1723642020"},{"product_id":"usg-white-hydrocal-50-lbs-bag-rmwhihyd50","title":"USG White Hydrocal  50 Lbs. Bag","description":"\u003ch2 class=\"abz-seo-product\"\u003eU.S. Gypsum WHITE HYDROCAL -REGULAR 50 lbs. Bag\u003c\/h2\u003e\n\u003cp\u003eWHITE HYDROCAL is used for making plaster objects, a neutral gypsum cement having a normal set of 25 minutes. When Gypsum Cement is formed under a template it is slightly on the “short side” and has a tendency to tear. The setting expansion is somewhat greater than ULTRACAL 30.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHYDROCAL White Gypsum Cement A neutral gypsum cement having a normal set of 25 minutes. When formed under a template it is slightly on “short side” and has a tendency to tear. The setting expansion is somewhat greater than with A-11 or B-11 cements, but higher wet and dry strength is provided.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSealers and Parting Compounds\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eParting compounds (also called “separators” or “releasers”) are needed to prevent adhesion of plaster or gypsum cement to patterns or models. They also permit removal of plaster or gypsum cement from the surface of the pattern or model upon which it “sets up.” Porous model materials require sealing prior to application of the parting compound.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eSealing \u003cbr\u003e\u003c\/span\u003eAll porous models, patterns and molds must be sealed before the parting agent is applied. Sealing is particularly essential for wood patterns to prevent dampness from causing the wood to swell, resulting in release difficulty. Gypsum cement patterns also require sealing to prevent them from absorbing water from the plaster mix and causing the mix to adhere to the gypsum cement pattern. Patterns of metal, glass, plastic and other impervious materials normally do not require sealing.\u003c\/p\u003e\n\u003cp\u003eA quick-drying lacquer applied by brush or spray gun is an excellent sealer for wood, plaster and gypsum-cement patterns and master models. Two coats of lacquer provide more resistance to moisture than shellac. Correct procedure is to reduce lacquer with lacquer thinner so that the model or pattern readily absorbs the first coat. Apply second coat after first coat has thoroughly dried.Where a plaster or gypsum cement pattern is used, apply lacquer immediately after set.\u003c\/p\u003e\n\u003cp\u003eMahogany patterns or models require special treatment because gypsum cement casts may adhere to undercuts caused by multiple pores or grain of the wood. A paste wood filler can be used to fill the grain of the wood, but should be reduced to a satisfactory brushing consistency with the recommended thinner. Apply a heavy coat and let it dull down; then wipe off excess by rubbing across the grain. After wood filler has set overnight, apply a coat of a clear acrylic sealer and allow to dry. Sand the pattern or model and apply several coats of a clear lacquer.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eSeparators \u003cbr\u003eSatisfactory separation agents must provide the following functions:\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003ePrevent adhesion to the cast.\u003c\/li\u003e\n\u003cli\u003eProtect and lubricate pattern surface.\u003c\/li\u003e\n\u003cli\u003eSpread easily and uniformly in a thin, continuous insoluble film.\u003c\/li\u003e\n\u003cli\u003eDo not react destructively with the plaster or gypsum cement surface, or with the pattern.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eSome of the most common and widely used separators are as follows:\u003cbr\u003eSoaps—A number of special “potter’s” soaps are available for use as parting compounds. “Green soap” (a liquid) is an effective parting compound when cut 10 to 1 with distilled water. Apply parting soap with a sponge and work into plaster surface. Several coats may be required on a new mold. Remove excess soap with a clean wet sponge before pouring mold.\u003cbr\u003eStearic Acid and Kerosene (Stearine)—Formula: 1\/4 lb. stearic acid shaved to flakes; 1 pt. kerosene.\u003c\/p\u003e\n\u003cp\u003eMelt stearic acid by warming:\u003cbr\u003eremove from heat source and add kerosene with constant stirring until a uniform mixture is obtained. Apply to pattern with a soft brush, preferably camel’s hair or sable hair. If brush marks show, thin mixture with more kerosene or by warming. This separator is one of the most widely used of all parting compounds and is particularly recommended for use with glue molds. Petroleum Jelly (Vaseline)—Formula: 1 part petroleum jelly; 2 parts kerosene. Use petroleum jelly if it is cut back with approximately two parts kerosene to one of jelly. Blend mixture by carefully heating and thoroughly stirring (Caution—Fire Hazard).\u003c\/p\u003e\n\u003cp\u003eApply the casting cement as a thin coat and brush out thoroughly.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: bold;\"\u003eFor special purposes, separators other than the above may be advantageous:\u003c\/span\u003e\u003cbr\u003eLight Lubricating Oil—Use sparingly.\u003cbr\u003eLight Mineral Oil—Particularly effective as a fine fog spray on metal patterns. Must be thinned to be effective.\u003c\/p\u003e\n\u003cp\u003eOlive Oil—May be used if applied carefully while warm. Crisco and other similar hardened vegetable oils used as frying fats are particularly recommended for use on lacquered wood.\u003cbr\u003ePowered Mica—Has been found useful when finely ground and added to most parting compounds. Satisfactory results have been obtained by adding 1\/4 to 1\/2 cup of the powdered mica to 1 qt. of parting compound solution.\u003c\/p\u003e\n\u003cp\u003eEPOXICAL® Mold Sealer Separator—Works well as a release agent of gypsum cements. \u003cbr\u003eThin EPOXICAL Mold Sealer Separator as it comes in the can, using white gasoline or kerosene at a ratio of 1-to-1 by volume. Apply a generous coat to the pattern: allow to dry 2 to 3 minutes and then wipe off excess with a soft cloth.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch2\u003eULTRACAL MIXING INSTRUCTIONS:\u003c\/h2\u003e\n\u003cp\u003eNormal Consistency 33 - 38 lbs. water\/100 lbs. product (15 - 17 kg water\/45 kg product) Hand Mix Vicat Set, Target 18 - 30 minutes Compressive Strength, One Hour After Set 2000 psi (13.8 MPa) Compressive Strength, Dry 6500 psi (44.8 MPa) Density, Wet 116 lbs.\/cu. ft. (1858 kg\/m3) Density, Dry 103 lbs.\/cu. ft. (1650 kg\/m3) pH Reaction Alkaline % Expansion, Final 0.08%\u003c\/p\u003e\n\u003cp\u003eNOTE The Typical Physical Properties in the above table were achieved under controlled laboratory conditions with freshly produced material, results may vary.\u003c\/p\u003e\n\u003cp\u003eUse potable water at temperatures between 70 °F (21 °C) and 100 °F (38 °C). Because variations in slurry (USG Ultracal 30 Gypsum Cement and water mixture) temperature produce variations in set time, it is important to keep both the USG Ultracal 30 Gypsum Cement and water in a stable temperature environment prior to use. The higher the temperature of the slurry, the shorter the set time. Conversely, the lower the temperature of the slurry, the longer the set time.\u003c\/p\u003e\n\u003cp\u003eWeigh both the USG Ultracal 30 Gypsum Cement and the water prior to use for each mix. The water-to-USG Ultracal 30 Gypsum Cement ratio is critical because it governs the strength and the density of the final cast. Sift or strew USG Ultracal 30 Gypsum Cement into the water slowly and evenly. Do not drop large amounts of USG Ultracal 30 Gypsum Cement directly into the water as proper soaking of the USG Ultracal 30 Gypsum Cement may not occur. USG Ultracal 30 Gypsum Cement should be fully dispersed in the water prior to mixing. Small batches require less soaking time than large batches. \u003c\/p\u003e\n\u003cp\u003eMixing USG Ultracal 30 Gypsum Cement slurry is one of the most important steps in producing USG Ultracal 30 Gypsum Cement casts with optimal strength, absorption, hardness and other important properties. Mechanically mixed slurries develop uniform casts with optimal strengths. USG Ultracal 30 Gypsum Cement can be mechanically mixed through both batch and continuous processes. Proper blade and bucket dimensions are important for obtaining the best batch mix (see USG IG503 Plaster Mixing Procedures for details). Longer mixing times result in higher mold strength and shorter set times.\u003c\/p\u003e\n\u003cp\u003ePOURING DRYING STORAGE AND USE PRODUCT INFORMATION See usg.com for the most up-to-date product information. DANGER Causes skin irritation. Causes serious eye damage. May cause cancer by inhalation of respirable crystalline silica. Do not handle until all safety precautions have been read and understood. Avoid breathing dust. Use only in a wellventilated area, wear a NIOSH\/MSHA-approved respirator. Wear protective gloves\/protective clothing\/eye protection. If swallowed, inhaled, or skin irritation occurs get medical attention. When mixed with water, this material hardens and becomes very hot sometimes quickly. DO NOT attempt to make a cast enclosing any part of the body using this material. If on skin: Wash with plenty of water. If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses and continue rinsing. Wash contaminated clothing before reuse. Dispose of in accordance with local, state, and federal regulations. For more information call Product Safety: 800-507-8899 or see the SDS at usg.com KEEP OUT OF REACH OF CHILDREN. \u003c\/p\u003e\n\u003cp\u003e. NOTICE We shall not be liable for incidental or consequential damages, directly or indirectly sustained, nor for any loss caused by application of these goods not in accordance with current printed instruction or for other than the intended use. Our liability is expressly limited to replacement of defective goods. Any claim shall be deemed waived unless made in writing to us within thirty (30) days from date it was or reasonably should have been discovered.\u003c\/p\u003e\n\u003cp\u003e SAFETY FIRST! Follow good safety\/industrial hygiene practices during installation. Wear appropriate personal protective equipment. Read SDS and literature before specification and installation. To prevent air entrainment and provide a uniform, smooth surface, careful pouring of USG Ultracal 30 Gypsum Cement slurry is necessary. Agitation of the filled mold is a further step used to prevent air at or near the mold surface. Whenever possible, USG Ultracal 30 Gypsum Cement slurry should be poured carefully in the deepest area so that the slurry flows evenly across the surface of the case mold. Pouring a large amount of slurry directly on the face of the case mold may result in slight densification of the USG Ultracal 30 Gypsum Cement mold at the point where it strikes the surface of the case. This produces a hard spot, giving uneven absorption.\u003c\/p\u003e\n\u003cp\u003eAll casts should be dried as quickly as is safely possible after manufacture so that maximum physical properties can develop. Dry to a constant weight. The best drying rooms or ovens provide 1) uniform and rapid circulation (minimum of 15-30 fps (4.6-9.1 mps)) of air with no “dead spots” having little or no air movement, 2) equal temperatures throughout the entire area, and 3) provisions for exhausting a portion of the air while replacing it with fresh air. High humidity surrounding the drying room or oven inhibits drying efficiency because the air pulled into the room is incapable of picking up much moisture from the molds. The maximum temperature at which USG Ultracal 30 Gypsum Cement molds are safe from calcination is 120 °F (49 °C). With substantial free water in the mold, a higher drying temperature can be used initially without difficulty. As drying progresses, the temperature must be reduced to prevent calcination. Before removing molds from the dryer, the temperature should approach that of the area around the dryer to prevent thermal shock.\u003c\/p\u003e","brand":"USG","offers":[{"title":"Default Title","offer_id":45113762251074,"sku":"RMWHIHYD50","price":37.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/gallery-large.876.657.jpg?v=1697054138"},{"product_id":"temporarily-out-of-stock-usg-dental-plaster-regular-101890-50-lbs","title":"USG Dental Plaster: Regular 101890","description":"\u003cdiv class=\"rm-testing-statement\" style=\"border:2px solid #8a5a00;border-radius:6px;padding:12px 16px;margin:16px 0;background:#fdf6e3;\"\u003e\u003cp style=\"margin:0;\"\u003e\u003cstrong\u003eYou must test before you use it, at any scale.\u003c\/strong\u003e Raw materials, mined or man-made, are not consistent. Setting time, strength, expansion and absorption can change from one bag to the next and from one supplier to another, even when the name on the bag stays the same. Before you pour a mold or casting of any size, mix a small test batch with your own water and mixing method, let it set, and check the results.\u003c\/p\u003e\u003c\/div\u003e\n\u003ch2\u003eUSG Dental Plaster: Regular 101890 50 Lbs.\u003c\/h2\u003e\n\u003cp\u003e\u003cspan id=\"product_description\"\u003eThe industry standard dental plaster.\u003cbr\u003eEasy to use; offers many applications for dental stones.\u003cbr\u003eSet time can be altered with accelerators or retarders.\u003cbr\u003eWater soluble so it requires no organic solvents for cleanup.\u003cbr\u003e\u003cbr\u003eUSG Dental Plaster Regular is a white dental plaster that can be used for a variety of purposes in a dental lab or office. It is designed for use in oral impression work and has a smooth consistency. It sets quickly to provide accurate and detailed impressions.\u003c\/span\u003e\u003c\/p\u003e","brand":"USG","offers":[{"title":"50 Pounds","offer_id":48292247339330,"sku":"RMDENPLA50","price":33.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/RMDENPLA50-2T_1.jpg?v=1712594918"},{"product_id":"georgia-pacific-k-59-plaster-50-lb","title":"Georgia-Pacific K-59 Pottery Plaster","description":"\u003cdiv class=\"rm-testing-statement\" style=\"border:2px solid #8a5a00;border-radius:6px;padding:12px 16px;margin:16px 0;background:#fdf6e3;\"\u003e\u003cp style=\"margin:0;\"\u003e\u003cstrong\u003eYou must test before you use it, at any scale.\u003c\/strong\u003e Raw materials, mined or man-made, are not consistent. Setting time, strength, expansion and absorption can change from one bag to the next and from one supplier to another, even when the name on the bag stays the same. Before you pour a mold or casting of any size, mix a small test batch with your own water and mixing method, let it set, and check the results.\u003c\/p\u003e\u003c\/div\u003e\n\u003ch2 class=\"abz-seo-product\"\u003eGeorgia-Pacific K-59 Plaster 50 Lbs.\u003c\/h2\u003e\n\u003cp\u003eGeorgia-Pacific K-59 is a pottery plaster for making slip-casting molds, press molds and other ceramic mold work. It produces dense, durable molds with smooth, pinhole-free surfaces, and is widely used as a substitute for USG No. 1 Pottery Plaster.\u003c\/p\u003e\n\u003ch3\u003eTypical Properties\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eConsistency: 68–70 parts water to 100 parts plaster by weight (can be reduced to 64 for stronger molds)\u003c\/li\u003e\n\u003cli\u003eVicat set time: 25–35 minutes\u003c\/li\u003e\n\u003cli\u003eSetting expansion: 0.22–0.27%\u003c\/li\u003e\n\u003cli\u003eDry density: 69–71 lb\/ft³\u003c\/li\u003e\n\u003cli\u003eCompressive strength: 2,000–2,600 psi\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eSold in 50 lb bags.\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/gpindustrialplasters.com\/pottery-plaster\/\" target=\"_blank\" rel=\"noopener\"\u003eGeorgia-Pacific pottery plaster technical data and Safety Data Sheet (SDS)\u003c\/a\u003e\u003c\/p\u003e","brand":"Georgia-Pacific","offers":[{"title":"50 Pounds","offer_id":67189298266483,"sku":"RMGPK59","price":31.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/files\/georgia-pacific-k-59-plaster.jpg?v=1792782493"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/5508\/2050\/collections\/fgr_hydrocal_1e45adea-ba2e-4f4f-a3af-e830c259c73c.jpg?v=1786648329","url":"https:\/\/www.sheffield-pottery.live\/collections\/us-gypsum-usg-plaster-information.oembed","provider":"Sheffield Pottery Inc.","version":"1.0","type":"link"}