| 摘要 |
A fiber-free plaster molding composition which comprises by weight approximately 50-70% gypsum plaster, 5-25% fine expanded perlite, and 5-30% of a non-fibrous filler such as mica, silica, fly ash, pyrophyllite or mixtures thereof. The composition of this invention has good dry blending properties, slurry characteristics, and wet and dry mold features, making it a suitable replacement for fiber-containing molding compositions for low fusion metal casting molds.
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