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Axismundi000
08-26-2016, 09:18 PM
My kiln goes up to 1000centigrade and Antimony oxide melts at 656centigrade. Reading the PDF by Steve Kalec they are going up to 1300centigrade to get the glass. I was wondering if anyone had insight into the need for such a high temperature.

Is it that the antimony melts at a fairly low temperature but you need it much higher for it to go to glass?

Illen A. Cluf
08-27-2016, 12:14 AM
My kiln goes up to 1000centigrade and Antimony oxide melts at 656centigrade. Reading the PDF by Steve Kalec they are going up to 1300centigrade to get the glass. I was wondering if anyone had insight into the need for such a high temperature.

Is it that the antimony melts at a fairly low temperature but you need it much higher for it to go to glass?

Adding Borax lowers the required temperature. I think that Steve Kalec used a temperature of 1,150 C, not 1,300. That's still above your temperature range.

JDP
08-27-2016, 03:38 AM
There's several antimony "glasses", and they might very well have different melting points. Many years ago I did some preliminary small scale tests of a "particular" silver-into-gold process by Becher and Stahl which requires a purplish antimony glass, made by first slowly calcining and stirring finely powdered antimony regulus, which forms a gray calx. Then you increase the temperature and this antimony calx melts into a purplish "glass". I carried out the whole thing on 50 ml porcelain crucibles on top of pipeclay triangles and heated with Fisher burners, the very same equipment that modern chemists use for their small scale operations:

http://jrdickie.tripod.com/sitebuildercontent/sitebuilderpictures/exp3crucible.jpg


So the melting points involved were all within the capabilities of gas flame blasts in the open air, no furnaces required.

Note to self and all those interested in these matters: one day I will revisit this "particular", as I have gained loads more knowledge and experience since those days. Maybe it actually works, as Becher and Stahl claim, even though my small scale tests did not look very promising. Once you realize that some "particulars" actually do work, but only yield tangible results when carried out on or after certain minimum amounts of the substances involved, it becomes obvious that sometimes smaller scale experiments might not only be useless but in fact right out misleading! So you could in fact be testing a successful "particular" and yet your smaller scale experiments might be giving you the wrong impression that it does not work. Ever since I discovered this fact, all my testing of "particulars" has been scaled up. For example, do not attempt silver-into-gold "particulars" using quantities smaller than about 10 grams of silver. Chances are that even if you stumble upon a successful one, the small gold yield simply won't be noticed with the naked eye if you use smaller quantities of the reacting materials.

Axismundi000
08-27-2016, 06:57 AM
Thanks for the factual info JDP.

You are right Illen A. Cluf they set it too 1150centigrade not 1300.

A Fisher/Meker burner will get to 800-900 centigrade with commonly available outdoor camping type gas bottles. I wondered why above a 1000 degrees was done in the Steve Kalec PDF because the expense of getting such high performance equipment was a discouragement to me. My existing kiln or a meker burner set-up are both more economic and doable.

To add a contribution here even though this is currently a thought experiment I'm thinking make a Kermes from stibnite then turn this to glass, grind, put with acetic acid, remove acetic acid put with Kerkrings menstruum, distil off Kerkrings menstruum to leave antimony oil like in Kalecs PDF. Seems straightforward but I didn't get why you needed 1300centigrade I was thinking no need to go above 900.

So this is to do with metal 'oil' not going after the stone.

Thank you.

JDP
08-27-2016, 07:38 AM
Thanks for the factual info JDP.

You are right Illen A. Cluf they set it too 1150centigrade not 1300.

A Fisher/Meker burner will get to 800-900 centigrade with commonly available outdoor camping type gas bottles. I wondered why above a 1000 degrees was done in the Steve Kalec PDF because the expense of getting such high performance equipment was a discouragement to me. My existing kiln or a meker burner set-up are both more economic and doable.

To add a contribution here even though this is currently a thought experiment I'm thinking make a Kermes from stibnite then turn this to glass, grind, put with acetic acid, remove acetic acid put with Kerkrings menstruum, distil off Kerkrings menstruum to leave antimony oil like in Kalecs PDF. Seems straightforward but I didn't get why you needed 1300centigrade I was thinking no need to go above 900.

So this is to do with metal 'oil' not going after the stone.

Thank you.

There are several reasons to consider in such melting operations. As pointed out already, some antimony "glasses" might in fact have higher melting points than others. Antimony seems to form several of these "glassy" products, depending on the manner of preparation. Another important factor is how much of the material are you going to be handling. I was able to pull off those small scale tests with that purplish "glass" of antimony just by using Fisher burners, pipeclay triangles and 50 ml porcelain crucibles because I was working with only a few grams of each of the substances involved in the process. So the output of a Fisher/Meker burner in the open air (no containment) was enough to keep everything in flux. If I put this "particular" to the test again in the future, though, this time the amount of the substances involved will be quite greater, so needless to say my Fisher burners are not going to cut it. I will have to use larger crucibles and either my electric or gas furnaces.

Axismundi000
08-27-2016, 11:39 AM
I appreciate your comments JDP. For me the point has been reached where practical research is perhaps the best way to address these questions of quantity and different glasses formed. The temperature issue was the concern that was discouraging practical work but now I feel it is worthwhile to commence. My kiln will take a 200ml crucible and if need be I can try a larger meker burner with a 200ml crucible and a larger upside down crucible to increase heat in my back garden on a sunny day. Steve Kalec did and example of the meker burner method on his yahoo website.

https://vimeo.com/178240415

This is why his earlier temp specified in the PDF baffled me, I always research if there is any available material before starting something.

http://www.magia-metachemica.net/uploads/1/0/6/2/10624795/tincture_of_antimony.pdf

Thanks for the input.

JDP
08-27-2016, 03:59 PM
I appreciate your comments JDP. For me the point has been reached where practical research is perhaps the best way to address these questions of quantity and different glasses formed. The temperature issue was the concern that was discouraging practical work but now I feel it is worthwhile to commence. My kiln will take a 200ml crucible and if need be I can try a larger meker burner with a 200ml crucible and a larger upside down crucible to increase heat in my back garden on a sunny day. Steve Kalec did and example of the meker burner method on his yahoo website.

https://vimeo.com/178240415

This is why his earlier temp specified in the PDF baffled me, I always research if there is any available material before starting something.

http://www.magia-metachemica.net/uploads/1/0/6/2/10624795/tincture_of_antimony.pdf

Thanks for the input.

As you can see from Kalec's demo, it is quite possible to melt some types of antimony glass by using simple gas burners in the open air, no heat containment necessary. But notice that Kalec was also demonstrating in a smaller scale. If you want to work with larger quantities you will need furnaces. Heat dissipation will limit how much material you can melt with simple Bunsen/Fisher/Meker burners.

One method you can also try without having to buy or build an actual furnace is to improvise heat containment around the porcelain crucibles being heated from below with a gas burner. You can use a simple steel can, like this:

https://sciencechristian.files.wordpress.com/2012/07/screen-shot-2012-06-26-at-2-54-30-pm.png

The steel can will prevent the heat around the crucible from dissipating too fast, so the temperature will increase. Even better than a steel can would be a piece of refractory ceramic blanket, such as used by potters to build their kilns:

http://www.bigceramicstore.com/cerablanket-fiber-blanket-1-linear-foot-2-sq-feet-8-1-thick-2-feet-wide.html

Shape it like a tube that surrounds the crucible, just like in the steel can method. Since these ceramic blankets are much poorer conductors of heat than steel/iron, with this you will be able to heat the porcelain crucibles even hotter. It is recommendable that you use long pipeclay triangles for such methods, and avoid as much as possible to apply too much heat to the steel wire parts of the triangle that are supporting the weight (the hotter they get, the softer they also get and thus will not be able to support as much weight.)

Axismundi000
08-27-2016, 04:10 PM
Thank you for this usefull practical info JDP, the ad hoc furnace using a meker burner and an upside down container I think is a very cost effective solution. Now that I can see there is some scope to operate at temperatures below 1000centigrade this is very workable. It will allow me to more readily observe the material and check with an iron rod how the glass has progressed, my kiln lacks practical versatility in this respect.