EpoxAcast™ 650 Black is a mineral filled general purpose casting epoxy that is low cost and versatile. It features a low mixed viscosity for minimal bubble entrapment. EpoxAcast™ 650 Black is used for making hard dies for metal stamping as well as patterns and fixtures. It is also used for electrical encapsulation to extend the life cycles and enhance the performance of potted electronic devices. The high compressive strength of EpoxAcast™ 650 Black makes it ideal for making stamping dies for production pressing of metal ornaments.
Preparation – Avoid breathing fumes - use in a well ventilated area at 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. EpoxAcast™ 650 Black Resin and Hardeners 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 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 Ease Release™ 200 or 205 (available from Smooth-On) 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.
Pre-mixing Part A – The fillers in this epoxy system will settle in the container over time. Before using, fillers need to be reconstituted by pre-mixing Part A thoroughly. The best method is to use a “turbine” mixer (available from Smooth-On) or similar drill mixer attached to a power drill and drill mix on medium speed for 2 minutes. Follow with hand mixing using a flat edge paddle for 1 minute until fillers are uniformly dispersed.
Measuring / Dispensing – The proper mixing ratio is 100 parts of EpoxAcast™ 650 Black resin to 14 parts 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 EpoxAcast™ 650 Black 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.
Mixing – 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 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.
Lowering Viscosity - Epic™ Epoxy Thinner is a clear, water-like liquid that will lower the viscosity of some Smooth-On casting and laminating epoxies. Epic™ is not a solvent and can be added in different proportions to improve flow-ability to make it easier to mix and pour or laminate. Epic™ will also aid in reducing bubble entrapment.
Increasing Flexibility - Flexer™ Epoxy Flexibilizer is a clear, low viscosity liquid additive that will lower the durometer (Shore hardness) of some Smooth-On casting and laminating epoxies. When added to the epoxy system in the proper proportion, the cured epoxy will be softer and, in some cases, can be made semi-rigid. See the Flexer™ Technical Bulletin for more information.
Pouring – If casting EpoxAcast™ 650 Black into a rubber mold, pour mixture in a single spot at the lowest point of the mold. Let the mixture seek its level. A uniform flow will help minimize entrapped air. If making vacuum forming molds, it is best to use piano wire (15/1000 inch gauge) to make vacuum holes.
Cure Time - Refer to specified Cure Times in Handling Properties at room temperature depending on mass. Cured material will be hard and unable to penetrate with a finger nail. 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.
Heat Curing - For best results, EpoxAcast™ 650 Black should be heat cured in an oven. Cure at 175°F / 80°C for two hours, followed by three hours at 300°F / 150°C. Allow material to cool to room temperature.
Painting – Cured EpoxAcast™ 650 Black can be painted and / or primed and then painted with acrylic enamel paints. Let paint fully dry before putting part into service.
Removing Epoxy – Uncured/ Non-curing epoxy: Scrape as much material as possible from the surface using a scraper. Clean the residue with E-POX-EE KLEENER™ available from Smooth-On, lacquer thinner, acetone or alcohol. Follow safety warnings pertaining to solvents and provide adequate ventilation.