Frequently Asked Questions
We have questions and answers to help you decode the terminology and the fundamentals of mouldmaking and casting.
- Is there a way to improve surface finish when casting a rigid or flexible foam? You can improve surface finish by applying back pressure. Photo Examples: Without applying back pressure, surface finish reveals open foam cells. Drill holes into a board that can cover mold opening during casting. Apply Ease Release®2831 to board. Pour foam into mold and place ...
- What is the best release agent for releasing concrete from a rubber mould? A: It depends on 1) the type of mould rubber you are using as your mould material and 2) the make up of your concrete ad mixture.1. What mould rubber are you using?Silicone rubber has the best release properties, but will succumb to the abrasive effects of the high-aggregate content of the ...
- What is pressure casting? Will it completely eliminate bubbles from my plastic casting? Pressure casting is the process of using a pressure chamber and compressor to eliminate bubbles from a casting resin or mould rubber. It is the best method for ensuring that castings are bubble free. The pressure casting method is commonly used by professional prototype model makers who cannot ...
- What paint should I use and how can I make paint stick to my resin castings? You have made the perfect mould and just poured Smooth-Cast™ liquid plastic into the mould to make a reproduction. The plastic cures, and you demould the piece to reveal a casting that looks exactly like the original. Your next step is to paint the casting for outdoor display, but when you try ...
- How can I avoid bubbles in my casting? Bubbles experienced while casting urethane resins are the nemesis of casters everywhere. As you may know, urethane resins are moisture sensitive, and often bubbles found in cured urethane plastic are a result of a reaction between the plastic in its liquid state and moisture coming from ...
- What is the heat resistance of rigid expanding foams? The heat resistance of rigid foams will range from about 110°F (43°C) to 125°F (52°C). There are variables that will affect the heat resistance of a foam casting: Higher density foams, such as FOAM-iT! 26, will have higher heat resistance than lower density foams, such as FOAM-iT! 5. ...
- What is rotational casting? Are some resins better for rotational casting than others? Rotational casting (also known as slush casting) refers to pouring a small amount of resin or other material into a rubber mold cavity and rotating the mold until the resin cures against the mold surface. Usually, a minimum of 3 to 4 successive pours are made into the mold, and layers are built ...
- Are any Smooth-On urethane or epoxy resins “UV Stable”? Stability in the presence of ultraviolet light or “UV Stability”, as it applies to resin products, is a fallacy. All resins will be affected by ultraviolet light over time and the best any resin manufacturer can offer are products that are “UV Resistant”. The effect of UV light on a ...