Over the past couple of months, we've been saving our glass bottles.
I don't have a kiln, but am interested in melting the bottles down into a clay potting tray and use them as stepping stones around the yard.

Has anyone melted glass down like this before? Or have any tips on how to do this?

Anealing temperature is critical to success in any glass slumping or melting endeavor. It can take many tries to get it right. Odd mixtures of stuff you've gathered will vary in this requirement. Buy a secondhand slumping kiln to experiment with.

A far simpler approach would be to pour concrete stepping stones with glass imbedded to create mosaics. The glass is laid out in the bottom of the mould and the concrete carefully poured or ladled on top.

Once the concrete sets, remove from mould and scrub the glass clean while it's still green. Rinse and allow to cure.

you could always scavange a big screen for the fresnel lens and melt the glass that way!
but yeah, annealing is neccessary

Would there be any benefit to smashing all your glass waste into small pieces, potentially working it into a sand-ish sort of mix?

Getting rid of glass is something, along with my paper waste, that I'm interested in doing. For paper, I'm thinking worms or mushrooms, but now leaning toward mushrooms. The idea of smashing glass down came to me recently. I think my neighbors would be much happier for it.

William

If you really want to do this do as follows

Use or acquire a computer controlled kiln or be prepared to waste 11 hours with a pyromoter to hand measure temperature and timing
place a stainless steel band (the glass industry makes all of these things for this delphi.com) in the diameter you want your 'stone'
line the band with 'fiber paper' usually 1/8 thick, line the bottom with 1/16 thick fiber paper
fill with scrap glass that all has the same COE
fire to 1600 and hold for apx 15 minutes
drop to 940 for 180 minutes
drop to 760 for 90 minutes
allow to cool

What are you trying to accomplish? A LOT of energy goes into slumping and melting glass. For me, that almost rules it out as a method, or moves it down to last resort.

Thekla

Thekla McDaniels wrote:What are you trying to accomplish? A LOT of energy goes into slumping and melting glass. For me, that almost rules it out as a method, or moves it down to last resort.

Thekla

That was my first thought as well. But if done in the winter, the Kiln could be operated within a heated space so that it replaces some other fuel. In the winter of 1999-2000, two electric kilns were my primary heat source.

makes more sense to me now! toasty warm, and in BC it is all hydro electric, and you're heating with it anyway!

thanks
T

There are many electrically heated homes in BC but it certainly isn't the trend anymore. I would say that most cheaper homes and multi unit townhomes and condos use electric heat. The majority of new homes in the cities use gas. Rural homes are more likely to burn oil, propane and wood.

Government disincentives against electric heat will make it less common. Usually, when I demolish a disposable 70s electric house, it is replaced by a much better one using gas.

Personally ,it might be pretty in the end but I really doubt that it is a smart way to go as far as being eco friendly...you are going to be wasting a LOT of kw hours just melting the glass down if you are using electric but if you have a cob kiln then by all means ...have at it, and good luck or unless you know how to blow glass and recycle it some other way.

Well thanks for all the input folks

I was really hoping that maybe I could just melt them down inside within a container like a a clay plant pot tray or such in hot coals from a winter nights fire.

The Fresnel lens seems great though! I wonder if you could melt down bits of old steel like that and make nails?

I have however been using whole glass bottles as automatic plant waterers for some container plants. It works well for larger plants with deeper roots [in a pot]

You can melt anything, as long as you can get the temperature above the materials melting point and contain the material all the way through the process.

I used to do glass blowing for fun and profit, it can get expensive if you buy all the gear at one time. blow pipes cost from 140.00 up to 350.00 depending on length, head size mouth piece type, any knurling for grip while blowing.

You would also want a pipe stand to hole the blow pipes when not in use. A blowers cradle, various shaping tongs, snips, cutter file and other goodies ( shapers and forms) some of which can be made at home.
Then there is the Annealing cabinet. They can be home made but you have to be able to heat the interior and then slowly reduce the heat so the glass you just created won't shatter or crack.