Making glass

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There are many kind of glasses

It's true if you've silica sand (very common), but there are feldspar sand e.g. In

You can try I think so>

Bye Luca

Yes, silica sand is mostly silica. There are also impurities.

Unfortunately silica melts at a very high temperature, and it is impracticable to make a low-quality glass block this way. First melt some glass, then press it in a mould, then anneal it. You need to make perhaps

When the first Survivor show was on television, I wondered how I would survive on a deserted island. Specifically, how could I create a means of obtaining fresh water in the dry season. Being an impractical lab rat, I immediately thought of making a distillation plant out of glass, using sea water. So where to get the glass? I'm not sure how well this would work, but I thought of grinding seashells (for calcium) and mixing it with the sand and, maybe, a little sea salt. How do you think this would work? Any other ideas?

Brendan Hall

Try a lot of sea salt. Roughly speaking you need 75 sand, 20 seashells, and about 30 salt, all dry weights.

Next you need to find a source of clay, to build the furnace and to make the pot in which to melt the glass. Presumably you have plenty of wood to fire the furnace.

Last of all, you will need an iron or steel tube to gather and blow the glass to make your tubing. Oh, and another person to hold the other end of the glass tube as you walk away from him to draw it.

That sounds like a Peace Corps project I heard about. They dumped a couple of ceramic engineers in god knows where and their job was to start a local ceramics (pots and such) and glass industry (cottage industry) from nothing but the raw materials in the region. The baked primitive brick in ground kilns (dig a hole - start a fire with charcoal - cover it up) and they used the brick to build a kiln so they could make real refractory brick. The real refractory brick was used to make a higher temperature kiln. The kilns were used to produce good earthen ware. They also smelted some glass (frit) for the glazes (I guess they had trouble developing a raw material glaze) sounds like a fun project. Gregg

It does indeed. Ceramic glazes vary a lot. The old salt glaze is relatively uncomplicated. Getting whites and colours needs some raw materials not usually found in your average locality. The major problem is matching the CofE for the body. A lot of trial and most of it error:-)