How to use epoxy casting resin?


How to use epoxy casting resin?

Table of Contents


– Avoid breathing fumes – use in a well-ventilated area at a minimum. NIOSH approved respirator is recommended. Wear safety glasses, long sleeves and rubber gloves to minimize skin contact.

Materials should be stored and used in a room temperature environment (73°F/23°C). Elevated temperatures will reduce Pot Life. Resin and Hardener must be properly measured and thoroughly mixed to achieve full, high-strength, solid-cure properties.

Because no two applications are quite the same, a small test application to determine suitability for your project is recommended if the performance of this material is in question.

Applying A Release Agent

– For releasing epoxy from non-porous surfaces such as resin, metal, glass, etc., use release agent to prevent adhesion.

IMPORTANT: To ensure thorough coverage, lightly brush the release agent with a soft brush over all surfaces of the mold or model. Follow with a light mist coating and let the release agent dry for 30 minutes.

Measuring / Dispensing

– The proper mixing ratio is 3 parts resin to 1
part hardener by weight. You must use an accurate scale (gram scale or triple beam balance scale) to weigh these components properly. Do not attempt to measure components by volume.

Mixing tools and containers should be clean and dry. Mixing should be done in a well-ventilated area. Wear safety glasses, long sleeves and rubber gloves to minimize contamination risk. Combine resin with the appropriate amount of hardener. Mix thoroughly for 3 minutes making sure that you scrape the bottom and sides of the container several times.

Adding Color

– Epoxy Resin can be colored with colorants or Cast Magic Effects Fillers. Pre-mix color or filler with Part A thoroughly and then add Part B.


– Be sure mixing utensils are clean and free of any potential contaminants such as dirt, dust or grease. Mix Parts A and B thoroughly for at least 3 minutes with a square-edged mixing stick. Be aggressive and scrape sides and bottom of mixing container several times. Use the square edge of mixing stick to bring material off of the sides of the container and blend. If using a drill mixer, follow with hand mixing as directed above to ensure thorough mixing.

Adding Fillers

– A variety of dry fillers can be added. Pre-mix dry filler with Part A before adding Part B.

IMPORTANT: Mixed epoxy resin is exothermic, meaning it generates heat. A concentrated mass of mixed epoxy in a confined area such as a mixing container can generate enough heat to melt a plastic cup, burn skin or ignite combustible materials if left to stand for its full Pot Life. Do not use foam or glass mixing containers or pour sections thicker than suggested thickness, If a batch of mixed epoxy begins to exotherm, move it to an open-air environment.


– If casting epoxy resin into a rubber mold, pour the mixture in a single spot at the lowest point of the mold or enclosure. Let the mixture seek its level. A uniform flow will help minimize entrapped air. Recommended casting thickness maximum SuperCAST31 is 1cm, SuperCAST 31 Pro is 3 cm, Deepour 21 is 5 cm

Layer Pouring

– When pouring epoxy resin in layers, allow the previous layer to fully cure and come to room temperature (73°F / 23°C) before pouring additional layers.

Cure Time: Refer to specified Cure Times at room temperature depending on mass. Cured material will be hard and unable to penetrate with a fingernail. Cured epoxy can now be dry sanded. If machining or sanding, wear NIOSH approved mask to prevent inhalation of particles. Pot Life and Cure Time values are dependent on mass and mold configuration, as epoxies are mass-sensitive. Let cure for 24 hours at room temperature. Castings that are ¼ in. the thickness or less will cure more slowly and may require up to 48 hours to fully cure at room temperature.

Performance: Cured castings are very hard and durable. They resist moisture, moderate heat, solvents, dilute acids and can be machined, primed/ painted or bonded to other surfaces (any release agent must be removed). If machining castings, wear a dust mask or other apparatus to prevent the inhalation of residual particles.

Castings can be displayed outdoors after painting with an aliphatic urethane clear coat (such High Gloss Polyurethane Topcoat ). Unpainted castings will yellow after being exposed to UV light or excessive heat above 115°F/46°C.

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