How Lost Foam Casting Works

Lost Foam Casting is a relatively new casting process compared to other metal casting procedures that date far back into antiquity. The first patent for Lost Foam Casting was made in 1958 but it was not until 1964 that what we know commonly as Lost Foam Casting was introduced.

Lost Foam Casting is a form of Investment Casting much like Lost Wax Casting. The key material of Lost Foam Casting is of course foam which is not used in other metal casting methods. The use of foam has many benefits to the artisan like ease of use and shaping and the relative inexpensive cost of the material. Each casting is going to be one of a kind since the original casting of foam is lost during the process.

The foam original will be replaced by the molten metal unlike the Lost Wax Casting where a wax mold is made of the original and then coated with a ceramic shell in preparation for the molten metal. Luckily, most foam is pretty inexpensive so the loss of the original shouldn't pose a significant financial loss, just an annoying creative loss.

Foam is easily shaped by hand held tools but even still some practice may be needed to prefect the sculpting of the material. You will need to place a sprue into the foam which will allow the molten alloy to spread into the foam and adopt the shape of the item. Packing the foam and sprue in sand is a good way to insure that the mold will retain its shape through the pouring process. The metal will replace the foam by vaporizing it, and it is really quite a sight to behold.

Though there are many who prefer to adopt the procedures used in Lost Wax Casting for the Foam casting. After spruing the foam original you are going to dip it into a solution to create a shell and then pour the metal. The goal of this is to create a cleaner surface.

Whichever method you choose is really up to you. Many use Lost Foam Casting a quick and easy way to create something when visual appearance isn't all that important. Many refer to Lost Foam as the "quick and dirty method".

As for the type of foam to use you are going to want to steer clear of anything that will give off toxic fumes when heated. Urethane foam is toxic. The popular foams to use are the polystyrene kind which is used to pack electronics and the polystyrene foam used for insulation. These foams can be found at many home improvement stores and even a few all purpose retail stores.

Lost Foam Casting is kind of like alchemy, transforming something inexpensive into something invaluable. Whenever you cast, make sure to take all proper safety precautions and wear safety gear. Always wear a long sleeve shirt, jeans, and the proper shoes. Don't forget eye and face wear and of course gloves. Never forget that you are dealing with material that can very easily harm and disfigure or worse if not handled properly.

Many first time casters begin with Lost Foam Casting since it doesn't involve mold making but if you are experienced and never attempted this method you will still want to be careful.