Choosing the Right Sand for Your Foundry
Posted on: 5 August 2020
Sand casting is not a new technique or process. It has been around for thousands of years, and modern-day sand casting uses much the same method as it did in the beginning with the exception of automated mold making and the sand used in the casting process.
1. Foundry Sand
A good quality foundry sand is critical to the casting process. It needs to be uniform in size, and grains need to be round and smooth. The more consistent the foundry sand, the better it sticks together in the mold, and the higher-quality casting will come out.
Casting with aluminum, steel, brass, or copper is all about the same, but the temperatures can differ between the metals, so it is essential to use a sand that can stand up to the metal you are casting with. If you are going to use a metal that is going to be extremely hot in your casting process, you need foundry sand with a higher tolerance for the heat, so talk to a foundry sand supplier about the option they have for the metal you are casting with.
The sand does not need to be wet to pack into the mold well, but it may feel a little damp to the touch. The sand you choose should be selected by your process as well. If you are hand-packing your molds and casting one part at a time, the foundry sand you use may be different than the sand used in an automated process where a machine is filling and packing the molds for you.
2. Ceramic Foundry Sand
In some situations, spending the extra money to upgrade the foundry sand you are using can have some significant benefits. The ceramic foundry sand on the market offers much higher silica content, and as a result, it can withstand higher temperatures without degradation of the sand. This allows you to use the ceramic foundry sand many times without a lot of sand loss.
Because ceramic foundry sand is man-made, it is also much more uniform than naturally occurring sands. The result is sand that packs in tighter and stays together better when setting up your molds. Since the sand pack is tighter, the chance or a blowout or failure of the mold when you are casting with it is much lower.
The upfront cost of ceramic foundry sand is higher than standard sand, but with the additional use and the improvements in the process, ceramic foundry sand may be an excellent addition to your casting process.
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