Greensand Casting Sand

Green sand is moulding sand that is used damp: fine silica sand bound by a little clay and water, so it packs firm round a pattern, holds a sharp shape, and lets steam escape when hot metal is poured. 'Green' means unbaked, not the colour. Bentonite clay is the usual binder; the mix is tempered with water until a squeezed handful holds its shape and breaks cleanly.

مبتدئ

1 hour

التعليمات

Sieve the sand

With a dust mask on, sieve dry fine quartz sand to remove stones and lumps.

المواد لهذه الخطوة:

رمل كوارتزي20 كغ

الأدوات المطلوبة:

منخل دقيق الشبكة

كمامة غبار

Add the clay

Weigh in bentonite at about a tenth of the sand's weight and mix it through dry in the trough until the colour is even.

المواد لهذه الخطوة:

طين البنتونيت2 كغ

الأدوات المطلوبة:

ميزان وزن

حوض خلط

كمامة غبار

Temper with water

Mist water over it a little at a time, rubbing the sand between your hands and through the sieve to spread the clay and water evenly.

المواد لهذه الخطوة:

ماء1 لتر

الأدوات المطلوبة:

بخّاخ ماء

منخل دقيق الشبكة

Squeeze test

Squeeze a handful. It should hold the print of your fingers and break cleanly in two when bent, not crumble or stick to your hand. Add sand if sticky, water if crumbly.