The binders of sand casting

● There are many types of binders are mixed with sand core. Binder should be selected on the basis of the characteristics that are most suitable for your particular use.

● Some binders require any baking becoming tight at room temperature, such as rubber cement, Portland cement and sodium silicate or water glass.

● In foundry operations in several large and small foundries, sodium silicate binder is popular because it can be hardened almost immediately blowing carbon dioxide gas through the mixture.

● process hardens the sodium silicate / CO2 via the following reaction:

sodium silicate

● binds the silica gel made individual sand grains together. Oil binders require heating or baking before they develop strong enough to withstand the molten metal.

● stickers require heat also sulfite. Most popular sulfite product stickers on the wood pulp industry.

● Many liquid binders made from starches, cereals and sugars. They are available with countless number of trade names.

Good binder will have the following properties;

- Strength

- Collapse quickly when metal starts to shrink.

- Not have a heart condition during baking.

- Maintain strength during storage time.

- Absorption at least in the mold or moisture when in storage.

- Withstand normal handling.

- Deploy correctly and fairly across the sand mixture.

- Should the production mix can be formed easily.

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