Gypsum Powder (Premium Iranian, Casting Grade)

Casting Grade Gypsum Powder, Alpha-Beta Hemihydrate Blend

This casting grade gypsum powder is a fine, super-micronized material made for mould casting, decorative crafts, model making and general plaster work. It mixes with water to form a smooth, pourable slurry that captures fine details and hardens with minimal shrinkage.

Compared with the fast-setting Plaster of Paris commonly sold in Sri Lanka, this gypsum plaster provides more working time. Once hardened, it produces a denser, heavier and less porous casting with a slightly off-white or ivory colour.

Plaster of Paris vs. Casting Gypsum Plaster? Plaster of Paris usually sets in about 15 minutes and produces a lightweight, porous, pure-white casting. It is easier to carve and sand. This casting gypsum plaster sets more slowly, normally within 30-60 minutes, and gives a smoother, denser and stronger-feeling finish.

Benefits & Advantages:

• Smooth slurry that flows easily into mould details
• Longer working time than fast-setting POP
• Produces dense castings with a smooth surface
• Minimal shrinkage during setting
• Suitable for beginners, craft makers and commercial production
• Can be tested with pigments, fibres, binders and selected plaster additives

Common Uses:

• Decorative trays, ornaments, plates, vases and containers
• Silicone mould casting and craft projects
• Models, figurines and sculptural work
• Cornices, trims and decorative architectural pieces
• Plaster repairs and surface patching
• Filler and raw material for suitable construction mixtures

Technical Details:

• Chemical name: Calcium Sulfate Hemihydrate
• Type: Alpha–beta hemihydrate blend
• Chemical formula: CaSO₄·½H₂O
• Purity: 95% or higher
• Particle size: 200 mesh, super micronized
• Powder colour: Fine white to off-white
• Hardened colour: Slightly off-white or ivory
• Setting time: Approximately 30-60 minutes*
• Origin: Gypsum mined in Iran and micronized in the UAE

* Setting time may change with water quantity, batch size, room temperature, humidity and mixing time.

Recommended Mixing Ratio

Always measure gypsum and water by weight.

• Thicker mix: 65 g water + 100 g gypsum - Produces a thicker mixture and generally a denser, stronger casting.
• Pourable slurry: 70-75 g water + 100 g gypsum - Flows more easily into detailed moulds. Too much water can reduce strength and extend drying time.

Mixing Tips: Place the measured water in a clean container. Slowly sprinkle the gypsum powder into the water and allow it to soak briefly. Mix gently until smooth, avoiding fast stirring that can trap air bubbles. Pour promptly after mixing.

The casting may set within 30-60 minutes, but complete drying takes longer depending on its size, thickness and weather conditions.

Storage: Keep tightly sealed in a cool, dry place. Protect from moisture and humidity.