A foundry core is fundamentally easy to make. With the right equipment, safety training and a bit of know-how, it can be done in a residential garage. It's amazing what can be achieved with wet sand, a blowtorch and some molten metal. For the hobbyist with no deadlines or production targets to meet, it can be a relaxing and gratifying pastime. If something goes wrong, you can re-use the sand and melt down your mistakes and keep trying until you get the result you are looking for.
If you have a small business casting metal, you don't have time for do-overs. If your foundry guy moves on to greener pastures, it can take a while to find someone with the same skill set and knowledge base. It's time to think about outsourcing your cores.
Almost 75% of all metal castings are performed using sand. There are a number of different methods for sand casting. Each approach has its own advantages. These methods include isocure, warm box, shell and air set no-bake.
The warm box process uses furan as a fixative. Furan is a small molecule, colorless and flammable. It's boiling point is near room temperature so it is also highly volatile. This work is probably best outsourced unless you have plenty of experience and the right set-up. Heat is applied until the outer surface of the core has hardened. The core's interior continues to cool once it has been removed from the heat. What you end up with is a core with a thin wall that won't be eroded or broken down on exposure to hot metal.
The air set no-bake process is ideal for complex designs in runs of low to medium volume. The process involves a proprietary mixture of sand and plastic packed around a "positive." The air set method produces castings between 40 and 225 pounds in weight. Another major benefit is that it works with a wide range of materials, including non-ferrous metals, wood, plastic, styrofoam and fiberglass.
The isocure method is the way to go for speed and economy when making large cores. Here, the sand is mixed with a polyurethane resin. An amine or other catalyst is injected to the box and then purged with superhot air.
Sometimes you need a light casting or a fine finish. Here, the shell process is used. In this process, the casting box is heated and pre-treated sand poured into it. In the absence of a catalyst, the exterior is heated to achieve a thin, hard shell. Another cool thing about this method is the sand inside remains uncured and may be poured out and used again.
Sand casting for foundry core production has been around since around 3,500 B. C.; that's way before even Moses walked the Earth. The reason it has stood the test of time is because of its reliability and versatility. Back in Moses' time, things were different and metal smiths had no problem melting down their mistakes. Over the years, the process has evolved in many different directions. It has always been a dangerous process. For many reasons, businesses today often outsource their foundry work.
If you have a small business casting metal, you don't have time for do-overs. If your foundry guy moves on to greener pastures, it can take a while to find someone with the same skill set and knowledge base. It's time to think about outsourcing your cores.
Almost 75% of all metal castings are performed using sand. There are a number of different methods for sand casting. Each approach has its own advantages. These methods include isocure, warm box, shell and air set no-bake.
The warm box process uses furan as a fixative. Furan is a small molecule, colorless and flammable. It's boiling point is near room temperature so it is also highly volatile. This work is probably best outsourced unless you have plenty of experience and the right set-up. Heat is applied until the outer surface of the core has hardened. The core's interior continues to cool once it has been removed from the heat. What you end up with is a core with a thin wall that won't be eroded or broken down on exposure to hot metal.
The air set no-bake process is ideal for complex designs in runs of low to medium volume. The process involves a proprietary mixture of sand and plastic packed around a "positive." The air set method produces castings between 40 and 225 pounds in weight. Another major benefit is that it works with a wide range of materials, including non-ferrous metals, wood, plastic, styrofoam and fiberglass.
The isocure method is the way to go for speed and economy when making large cores. Here, the sand is mixed with a polyurethane resin. An amine or other catalyst is injected to the box and then purged with superhot air.
Sometimes you need a light casting or a fine finish. Here, the shell process is used. In this process, the casting box is heated and pre-treated sand poured into it. In the absence of a catalyst, the exterior is heated to achieve a thin, hard shell. Another cool thing about this method is the sand inside remains uncured and may be poured out and used again.
Sand casting for foundry core production has been around since around 3,500 B. C.; that's way before even Moses walked the Earth. The reason it has stood the test of time is because of its reliability and versatility. Back in Moses' time, things were different and metal smiths had no problem melting down their mistakes. Over the years, the process has evolved in many different directions. It has always been a dangerous process. For many reasons, businesses today often outsource their foundry work.
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