Hi i am a glass maker. I get sand i put in a very hot fire and wait for it to melt once it has melted. I get my special tools and i blow into a pipe and it creates a glass bubble then i put it into a heated mold. When i mess up i restart the glass. Glass has to be cooled here or it becomes brittle. Lots of hands are needed to make glass cause we keep it very hot.Blowing through the pipe takes lung power in order to rest my heart in.The place that we work it is very hot.I only work six to nine months a year.Soda-lime glass was the first stuff i worked with it was dark but not very clear the soda-lime glass was better for windows than it was oilskin. flint glass was made later but it was stronger and could hold better.