Many people make chalk only using calcium carbonate and distillate water . If only use this recipe very possible if quality chalk that produced is not good, chalk that only made this combination often frangible. This recipes not only contains to make white chalk, but colored chalk (pastel) too. Although in advance country much school had using white board that using board marker, but in develop country much school still use the black board that using chalk. Maybe these recipe can be useful
INGREDIENTS:
* 400 gr of Calcium carbonate (limestone)
* 1000 cc of Distillate water
* Dye (aniline) (adequate)
* 600 gr Plaster of Paris
UTENSILS :
* Plastic pipe 8 cm long and 1 cm diameter (mould) as much as 40 stem
* Pan
* Safety gloves
* Rab
HOW TO MAKE :
* Heat 1000 cc of distillate water inside pan till boiled , after boiled put chemistry dye (if you want to make pastel (colored chalk)) inside it and stir it using Rab till evenly.
* After the distillate water has boiled , put inside pan 400 gr of calcium carbonate and 600 gr Plaster of Paris and wait till it become like pulp.
* Prepare your mould , and pour that pulp in to the mould wait till coagulate +- 24 hour or one day. after it coagulate push it slowly so that the chalk not break.
Note : not all of chalk can be coagulate , because of that you must made it as much as possible
WHERE WE BUY THE INGREDIENT;
* Plastic pipe , Plaster of Paris and calcium carbonate you can buy in building material store.
* Distillate water you can buy in chemistry store
