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2 of the Most Common Types of Foundry Casting
Methods and Why It Matters

At Montclair Bronze, we get casting projects of all shapes and sizes.  However, it’s not always the dimensions of the job that decide which methods we use. If anything, this most often has to do with the project’s alloy(s), and more often, the particular purpose or application that the product is made for.

This is one reason why a good foundry will use a very different casting method for an artistically designed bronze sculpture, as opposed to, say, an industrially developed part. Here are two of the most common types of foundry casting methods that we use here at Montclair Bronze -and why it matters for the manufacturing your particular project.

Investment Casting (Sand Casting)

The investment casting method is, by far, the oldest foundry technique of them all -considering how carbon dating of certain historical artifacts puts investment casting (otherwise known as lost-wax casting) at 4,500 BC.  In those days, ancient foundries would use molds, made of beeswax.  These days, however, methods have become a great deal more precise and sophisticated.

The reason why investment casting is still used, even into the 21st century, is because of how versatile and artistically precise it is -providing sculptors with the means to use various metal alloys as their medium.  Also, there are quite a few alloys that can be used in this type of casting method, such as…

• Bronze
• Iron
• Steel
• Brass
• Aluminum
• Magnesium
• Lead
• Tin
• Zinc

Advantages - The advantages of investment casting offer a reliably workable method of forming just about any alloy into unique and artistically designed shapes and patterns. Also, through modern techniques that utilize ceramics and sand (hence the name, sand casting), the finished product comes back with minimal defects and relatively little processing after the initial casting has been finished.

Limitations - Investment casting does fall short when it comes to projects requiring industrial precision for machine parts, like propellers and wheels.  In addition, manufacturing costs and longer job turnaround times make the method infeasible for mass production.  Basically, investment casting is excellent for artists and designers, but not so great for mass manufacturers.

Centrifugal Casting

The method was first pioneered by Alfred Krupp in 1859 for creating cast steel tyres for the railway industry.  If anything, whereas centrifugal casting might fall short in its utility for artistic applications -it shines where high precision dimensions and extremely low metallurgical imperfections are required.  Here’s a quick video on how it’s done on a small scale to give you an idea on the basics of how the process is performed.

Also, the list below shows which alloys can be used with centrifugal casting method…

• Iron
• Steel
• Stainless steels
• Aluminum
• Copper
• Nickel

Advantages - This type of casting method is incredibly useful for when a perfectly axi-symmetrical part is required, which must also sustain perfect rotational balance and metallurgical consistency. The process itself essentially molds the molten alloy by creating these geometrical attributes through the use of natural gravitational forces involved in the centrifugal casting process.

Limitations - Centrifugal casting is not, however, useful for sculptors -as the process itself is subject to a few rigid design parameters. Essentially, it’s primary use is for industrial applications; yet has the capacity to produce a flawless, precision product with extremely high consistency.

Why It Matters For Your Foundry Casting Project

Whether you’re a sculptor in search of a foundry that can reproduce an identical bronze form of your artistic piece, or you’re an industrial manufacturer that needs to mass produce an engine flywheel or propeller -your project will most likely be manufactured, based on the use of these two primary casting methods.

That’s why it’s important to speak with a foundry, who will be able to identify the best method for your project -because when it comes to castings- the production process matters just as much as the product itself.