Work / Gypsum

A quick note on gypsum;

Gypsum is in my opinion one of the building blocks of civilisation, excuse the pun. Seriously though for me it ranks alongside timber, the wheel and the internal combustion engine. I should do a post about that.

So gypsum; its a non mettalic mineral found in rock form. It can be white, grey, pink even almost black. The magic thing about gypsum is that it contains water which is dry, scientifically known as water of crystallisation - this solid water will not blink an eye till it gets heated to 100 degrees centigrade. At which point it will become water vapour.

Now that's a really crucial part as to why gypsum is used so widely in modern building practises, well actually its been used throughout the ages in building practises for its many differing properties and who knows maybe in the future some bright spark might figure out a new application for it. But before that happens take as a current example drywall also known as plasterboard - plasterboard is made of gypsum sandwiched between two sheets of lath (paper). The gypsum in the plasterboard will not exceed 100 degrees centigade until all the crystalised water has been released as vapour. Hence the fire retarding properties, even if the room is at a temp far higher than 100 degrees centigrade, the plasterboard wont exceed 100 degrees centigrade. Once all the crystallised water has been released as vapour, your buggered but on the whole it will give you have about 15 -20 minutes of fire protection depending on the thickness of the gypsim in the plasterboard, which is more than enough for fire alarms to kick off and give you a head start.

So in summary gypsum offers great fire protection.

Also, gypsum rock can be ground up and heated until most of the water has been removed, btw this 'calcined gypsum' was used by the egyptians as cement and by a lot of other people for a lot of other things. The reason why it was popular amongst our ancestors was that it really didnt take that much heat to calcine gypsum. Anyway, if water is then added to calcined gypsum it forms a plastic mass known as plaster of paris this can be moulded into any desired shape after which it will harden and retain that shape - it returns to its originl rock like form, the only natural substance that has that property, no less than amazing. Another form of gypsum is selenite - selenite is transparent and was used by the greeks in their temples as windows. Sweet.

Believe me reader gypsum pops up everywhere, i am not kidding. Its an invaluable mineral that's been crucial to building throughout mankinds long history. I am very surprised that it is so unknown, i mean if everything we know of went tits up in a big way, along with your Ray Mears survival skills pocket handbook you would really want to know about gypsum.