VAGABOND CORPORATION
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General Instructions For UseMODEL-CAST POLYURETHANE CASTING RESIN is formulated to be mixed one to one by volume. The material will tolerate an off-ratio condition of five to ten percent without noticeable degradation in casting quality. Some special formulations are compounded to be mixed one to two by volume. The ratio instructions will be indicated on the product label. MODEL-CAST is formulated to be stored and used at or above seventy degrees Fahrenheit. Material used at a lower temperature will gel slower. If the 'A' side temperature drops to fifty degrees F or lower the extenders will separate out and the material will be unusable. The separation is reversible by raising the temperature to seventy degrees F and agitating the containers to mix the ingredients back into solution. Material used at higher than seventy degrees F will result in a faster gel time. Casting quality will not be effected. MODEL-CAST components are very hygroscopic. Exposure to moisture will seriously effect performance by causing a foaming action and separation of extenders. It is an indication of moisture presence in the material or filler if the material rises when the 'A' side and 'B' side are mixed together. Avoid introduction of moisture during all stages of the casting evolution. Reseal containers immediately after pouring. We do not recommend using squirt or pump top bottles because they suck in air and the MODEL-CAST will absorb moisture from the air. Use only polyethylene, glass or un-coated paper cups for mixing. The wax coating on some paper cups and styrene foam cups are also incompatible. MODEL-CAST components are very miscible with a minimum of mixing effort. The 'A' side should be poured into the mixing cup first. The 'B' side of the material should be poured in on top of the 'A' side and stirred for about thirty seconds with a wooden stir stick to mix thoroughly. Large quantities can be stirred with a Jiffy Mixer attached to a drill motor. Care should be exercised to mix the material thoroughly but not to excess, which can cause air bubbles. We do not carry Jiffy Mixers but they can be purchased from Urethane Services, Incorporated. Their phone number is 800-521-3242. MODEL-CAST should be poured into the mold before the gel time that is specified for each formula. Most gel times are two to three minutes. You will find the gel times listed on our MODEL-CAST FORMULA LIST. Care should be taken to not disturb or move the mold when the resin begins to gel. De-mold the part when it no longer feels rubber-like to the touch. Normally this takes about four to five minutes. You will have to judge de-mold time for the amount of material poured and the size and shape of the part. If the part is left in the mold to long it will be difficult to de-mold and mold life will be shortened. Place the finished part on a wood insulated surface to completely cure. A metal or plastic surface will cause unequal cooling and possibly warping. We recommend curing for twenty-four hours at room temperature. Shrinkage is approximately one percent and depends on the size and shape of the part. Any sanding, painting or other finishing work can be done when the part is completely cured. Any paint that is not water based can be used. Water based paints will not adhere to the surface of the finished part. The following links will take you to information on products that can be used with MODEL-CAST. RTV SILICONE RUBBER AND THINNER
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