Making a foundry core is not brain surgery. Provided you have the materials, the safety equipment and the know-how, it can be done in a garden shed. It's awesome what can be produced using a blowtorch, a bag of sand and hot metal. It can be a relaxing and productive pastime for the DIY enthusiast who has plenty of time and no deadlines to meet or targets to worry about. There is time to melt down and re-pour your mistakes until you are happy with the result.
If, on the other hand, you are an independent business, there is no time for doing things over until you get it right. If your foundry personnel move on, retire or get sick, you can be up spit creek. When this happens, outsourcing your cores can be the smart move.
There are several types of core-making process. These are warm box, isocure, air set no-bake and shell. Each one has its own strengths. Nearly three quarters of all metal castings are produced using a sand casting process.
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.
When you are looking for a fine-grained finish, the shell process is the method of choice. Heat the casting box and pour in pre-treated sand. Apply heat to the outside to get a hard, thin shell. A side benefit of this approach is the sand on the interior remains uncured and can be reused.
Metalsmiths have been using the sand casting process for foundry core production for more than three thousand years. This is how our museums became filled with elaborate artifacts from ancient civilizations. Back then, it was a simpler, slower time. Today, not only is there more pressure to produce and produce quickly, techniques have come a long way in five thousand years. They are not necessarily more complicated but they do incorporate more hazardous materials. These are just a few reasons why oursourcing this work is to be recommended.
If, on the other hand, you are an independent business, there is no time for doing things over until you get it right. If your foundry personnel move on, retire or get sick, you can be up spit creek. When this happens, outsourcing your cores can be the smart move.
There are several types of core-making process. These are warm box, isocure, air set no-bake and shell. Each one has its own strengths. Nearly three quarters of all metal castings are produced using a sand casting process.
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.
When you are looking for a fine-grained finish, the shell process is the method of choice. Heat the casting box and pour in pre-treated sand. Apply heat to the outside to get a hard, thin shell. A side benefit of this approach is the sand on the interior remains uncured and can be reused.
Metalsmiths have been using the sand casting process for foundry core production for more than three thousand years. This is how our museums became filled with elaborate artifacts from ancient civilizations. Back then, it was a simpler, slower time. Today, not only is there more pressure to produce and produce quickly, techniques have come a long way in five thousand years. They are not necessarily more complicated but they do incorporate more hazardous materials. These are just a few reasons why oursourcing this work is to be recommended.
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