Could I melt glass using a leaf blower, a small homemade kiln make of bricks, charcoal, and a good design?
I tried this using a not too thick clay pot with a little “bite” taken out of the lip of the pot. I put a small amount of charcoal on flat ground, burned it a while, covered the charcoal with the overturned [broken] pot, and pumped air into it with a leaf blower. It only took a few seconds for the pot to break into pieces. I was just wondering if this could get hot enough? ~1500*C? assuming I build a good medium size kiln of sorts out of spare bricks.
The simple answer might be yes, but the chances of it working are actually pretty small – certainly without a lot of charcoal and the right kind of bricks. I took some classes in glassblowing and then started off really cheap and built a newsletter http://www.mikegigi.com/hb-toc.htm and a website http://www.mikegigi.com/sitemap.htm that are still available and updated.
To begin with, you heated the pot much too fast which causes shattering of pottery just like glass shatters when heated too fast. But if you had succeeded in keeping that intact, the losses of heat into the ground and air through the uninsulated pot material would have limited the temperature gain, using up the charcoal quickly.
A piece of good news is that glass melts at a much lower temperature than you were trying for – in fact 1500F will make most glass melt flat if not really workably molten. 1500C is 2732F (for my reference) and that would turn most household and art glass to a bubbling mess. Art glass is cooked from batch raw materials at about 2400-2450F, is melted from cullet at about 2200F and is worked from molten at 2000-2100F depending on the preferences of the gaffer.
To melt glass with charcoal and a blower – and a leaf blower is probably too much air – you will need to buy or make some insulating firebrick or other refractory for insulation around and below a container to hold the glass. You will have to build the heat up gradually to avoid shocking, to drive off moisture, and to heat the materials. To heat a space about 6x6x6″, I would guess you would have to have a bag of charcoal added to an adjacent burning chamber. And you would have to have an exit point, a flue/chimney, that would allow the hot gases to heat the glass and leave.
At various times in history (and today in India) glass has been produced with wood, charcoal, and coal fires. Although I don’t detail it much on my site, there are some pictures, etc.
This link http://www.mikegigi.com/furnaces.htm#GLORYH goes to the discussion written at the time of my first pathetic efforts. Above and below it on the same page are more advanced discussions.
Tags: charcoal kiln designs
