Application InstructionsDownload PDF

Application Instructions

R&R GLASS-CAST mold materials have been successfully used for pate de verre, kiln-cast and crucible casting processes.

Mold Making
Mix 100 parts R&R GLASS-CAST powder to the appropriate parts water by weight (refer to table below for specific R&R GLASS-CAST products). Mix for 2-3 minutes. R&R recommends mechanical mixing to achieve the best mixing action. It is possible (but not required) to vacuum the mix until the investment rises and breaks to eliminate entrapped air before pouring around the pattern.

Pour the R&R GLASS-CAST mold material down the side of the flask or mold frame until the patterns are covered to an appropriate depth. This depth will vary depending on the size of glass casting and the strength of the mold material you use. It is possible (but not required) to vibrate or vacuum the mold to remove air bubbles, which may adhere to the patterns. This operation normally takes 1-1½ minutes. R&R recommends that the mold then sit a minimum of 1 hour after it has set, before moving onto pattern removal.

Pattern Removal
Re-usable patterns ― after waiting a minimum of 1 hour, re-usable patterns can be physically removed from the mold.

Wax patterns ― two methods of wax removal are commonly used: dry dewax and steam dewax. For dry dewaxing, place the mold into a kiln or furnace at a temperature of 300°F-350°F (149°C-177°C) and hold for 3-4 hours. For steam dewaxing, place the mold into the steam dewaxer. Steam dewax only for the time required to remove the wax and no longer. The amount of time required to dewax the molds will vary depending on the size of the mold. After steam dewaxing, it is recommended to immediately move to the curing of the mold.

Mold Curing
After the pattern is removed, place the mold into a kiln or furnace at a temperature of 300°F-350°F (149°C-177°C) and hold until the water is removed from the mold. The temperature of the mold can then be raised to desired casting temperature at a rate of 150°F-200°F (66°C-93°C) per hour.

Glass Application
Once the pattern has been removed, glass frit can be placed into the mold at any time during the process. The glass can then be heated at the same time as the mold. When crucible casting, it is important to have all water removed from the mold before casting. It is recommended that mold temperature be at least the desired annealing temperature of the glass.


R&R® Glass-Cast™
101 BANDUST™ investment

R&R® Glass-Cast™
400 investment

R&R® Glass-Cast™
910 investment

R&R® Glass-Cast™
965 investment

Water/Powder Ratio 40/100 34/100 28/100 28/100
Pour Time 10-15 minutes 10-11 minutes 10-11 minutes 9-10 minutes
Set Time <25 minutes <20 minutes 14-17 minutes 11-13 minutes
Slump 4-5 inches 4½-5 inches 4-4¼ inches 2¾-3⅛ inches
Green Compressive
400 psi 680 psi 1000 psi 700 psi
Post Fired Compressive
40 psi 100 psi 150 psi 130 psi
Mixed Density 1.75 g/ml 1.82 g/ml 1.88 g/ml 1.87 g/ml
Permeability (Darcy) 0.045 0.036 0.020 0.050
Maximum Casting
1540°F (838°C) 1540°F (838°C) 1540°F (838°C) 1540°F (838°C)

US: Danger. May cause cancer by inhalation. Causes damage to lungs through prolonged or repeated exposure by inhalation. Contains crystalline silica. See SDS for more information.
EU: Danger. Causes damage to lungs through prolonged or repeated exposure. Contains respirable crystalline silica. See SDS for more information.

As the conditions or methods of use are beyond our control, we do not assume any responsibility and expressly disclaim any liability for any use of this product. Information contained herein is believed to be true and accurate but all statements or suggestions are made without warranty, expressed or implied, regarding accuracy of the information, the hazards connected with the use of the material or the results to be obtained from the use thereof. Compliance with all applicable federal, state, and local regulations remains the responsibility of the user. All potential liability related to the sale and use of this product is limited to the cost of the particular goods sold in their respective transactions.