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ldanielrosa
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Would a two part, bolt together retort with a recess for a silicone O-ring be of any use? The bolts needn't put much mechanical stress on the
ceramics- just finger tight with all external hardware. If the thermal conductivity is low enough the O-ring would be the same temperature as the
vapor.
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Sedit
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I finished my microkiln last night and for the first time got it up to full power since the first couple firings where just to remove latent water. I
was impressed that such a simple design allowed me to reach in excess of 1800 degrees F. I fired a small crucible I made in it then used that to melt
Aluminum with a propane torch just as a test. Sadly the crucible cracked but this has more to do with the state of the clay when I made the crucible.
It was just quick and dirty and I never completely mixed the clay so the cracks that appeared where already there before I even fired it and they just
reappeared after the torch hit it. The good parts of the crucible stood up to a direct attack from the torch with ease even though it was bitter cold
to start with so this is a very good sign even though I used shitty clay to start with.
I also used my lil' kiln to glaze a small plate I made some time back and was impressed by the quality of the firing.
I will soon post pictures and instructions on my kiln since its something that everyone can make since the heating element is nothing more then an old
electric stove element, some rarefactory cement which I can show how to make, and an old abestos pipe liner for the body of the kiln.
Im working on a retort out of pipe fittings and later tonight im going to use it to make White phosphorus. Wish me luck.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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not_important
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Quote: Originally posted by ldanielrosa  | | Would a two part, bolt together retort with a recess for a silicone O-ring be of any use? The bolts needn't put much mechanical stress on the
ceramics- just finger tight with all external hardware. If the thermal conductivity is low enough the O-ring would be the same temperature as the
vapor. |
Can't get it very hot, silicones generally are for below 300 C and many of the processes people want to do run 500 C on up.
We used thick slabs of castable insulation as standoffs for homebrew C-clamps with springs applying force to the standoffs. That gave the clamping
enough 'give' to avoid stressing the lips, and avoid holes in the rims as well. You can add lightweight insulating shells as shields against thermal
radiation from the vessel for the clamps; useful if things are really toasty.
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Sedit
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I have something to add and even though I should add it in the thread I hope to start soon on the contruction of my kiln I noticed that the
temperature rose very quickly after I opened the lid for a few seconds, maybe 30 or so in all. At that point it stalled around 600 degrees C so I
opened it in order to see inside and quickly afterwards the temperature shot up to 900 degrees C. Im not 100% sure why this is and I am going to test
it again because my kiln is almost at 600 degrees again so im going to let it stall there for about 1 hour, if it decides to do so that is, and then
open it to see if I get the same effect.
It may be coincidence however because the Cal-Coat that I made the insulation out of says that its rated for 600 degrees C, which I took as the
theoretical limit of my kiln, so I think it may be reacting in someway at that temperature and it holds there until the insulation is fired at which
point it stops absorbing the heat and allowed it to proceed to a higher temperature.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Sedit
International Hazard
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Im still working on all of this folks don't count me out. I just purchased a new kiln, a smaller one, yesterday and I am going to pick up the alumina,
kaoline, silica ect... next weekend at the latest.
I have to learn new skills since Im a sculptor and im use to working clay free hand yet this is requiring that I use molds and forms to work on else
there will not be consistancy to the work. So now I have to learn to work in the negative and practice making plaster and concrete molds.
Its touch and go at the moment but going ok non the lest.
However I wanted to ask people. On a little research I seen that many tube furnaces are around $1000 and up. If I where able to offer them for maybe
around $500 would anyone be interested?
Im making one myself right now and I will be firing the center tube tommorow morning. Its diameter is about an inch and a half but thats all on a whim
and I could customize things with ease.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Morgan
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I have several meter lengths of wave guide fused quartz made by Heraeus 25mm X 19mm and have often wondered how/where to melt it and shape it for
some experiments. I don't have a hydrogen/oxygen torch. It was for making fiber optic cable. Quartz has a very low thermal expansion coefficient and
the beach sand where I live is almost pure quartz too. Thin sheets of red hot quartz can be dipped in water without cracking. The quartz for these
tubes was mined in Madagascar.
Quartz has a lower melting point than Al2O3 but it has some advantages.
http://www.heraeus-quarzglas.com/en/quarzglas/thermalpropert...
The internet really is a series of tubes. ha
If you watch this video, it shows the process of making fiber optic cable, some good food for thought.
http://www.youtube.com/watch?v=llI8Mf_faVo
http://en.wikipedia.org/wiki/Fused_quartz
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Sedit
International Hazard
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Im not 100% sure on an industrial scale how they do it but ways of fusing quarts involve getting really fine silica flour and adding a binder to it
like CMC or gum acacia to assist in its binding. You can cast it into a mold at this point and when fired it shrinks and fuses into crystal. This is
the process a glass artist told me about. When fusing it you don't need to really liquify it completely only sinter it enough that it fuses with the
fine particals next to it.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Morgan
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Do you happen to know the basic formula for the material used in spark plugs? Is it a blend of SiO2 and Al2O3 with other ingredients? It's so hard my
grinder won't touch it and neither a bi-metal hacksaw blade. It seems like sapphire.
I have a diamond saw that I cut my quartz tubing with.
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Morgan
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Here's how they made fused quartz in 1924. Kind of thought provoking.
"The quartz is made in specially constructed, vat-like, electric furnaces operating at times in a vacuum, and at other times under a pressure of 1,100
to 3,000 pounds of nitrogen to the square inch, or more than a million pounds on the top of the furnace. If the pressure were unloosed it would have
the effect of a high-explosive bomb. The quartz is forced downward through the crucible' by a weight, and cut into tubes as it emerges. The product is
to the eye a beautifully fine, clear, color- less substance."
http://www.time.com/time/magazine/article/0,9171,718367-1,00...
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Sedit
International Hazard
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Sapphire is nothing more then Alumina doped with things like Chromium and Titanium so odds are you just have either fused Alumina on the spark plug or
a very high Alumina porceline. Given that your grinder is also Alumina it would cut into it just very very slowly.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Melgar
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A while back I was trying to design an electric crucible that could melt and electrolyze salts. It would have a lid to keep oxygen from reaching the
metal, and a tube that would allow collection of the chlorine/bromine vapor or whatever came off that electrode. Cheap easy access to alkali metals
and halogens would be pretty awesome.
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Morgan
International Hazard
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Yea, it's kind of funny how if it's red they call it a ruby and all the other colors are sapphires. I have a ruby rod I bought on eBay but the ends
aren't polished. Minerology is an interesting field too. There're all sorts of combinations/blends found in nature.
Have you ever melted Al2O3 and gotten a clear material? I think it's pretty hard to do.
I just now took a Motocraft spark plug and pressed it up against the edge of my 6 inch grinding wheel for several seconds. It's ever so slightly
abraded looking at it under an 8 inch lens. It's hard stuff. Some very old spark plugs are pink containing/to indicate beryllium oxide, you wouldn't
want to grind those. I read some microwave ovens have beryllium oxide insulators so if you fiddle with ceramics, make sure you aren't inhaling dust
from these sources.
Here's some various ways fused quartz and fused silica are made. The synthetic fused silica seems challenging. ha
"Fused quartz and fused silica are types of glass containing primarily silica in amorphous (non-crystalline) form. They are manufactured using several
different processes."
"Fused quartz is made by melting high-purity naturally occurring quartz crystal at around 2000°C using either an electrically heated furnace
(electrically fused) or a gas/oxygen-fuelled furnace (flame fused). Fused quartz is normally transparent."
"Fused quartz can also form naturally. The naturally occurring form of fused quartz is usually referrred to as Metaquartzite and is formed under
metamorphic conditions. Due to increased heat the crystals within the quartz become fused together."
"Fused silica is produced using high purity silica sand as the feedstock, and is normally melted using an electric furnace, resulting in a material
that is translucent or opaque. (This opacity is caused by very small air bubbles trapped within the material.)"
"Synthetic fused silica is made from a silicon-rich chemical precursor usually using a continuous flame hydrolysis process which involves chemical
gasification of silicon, oxidation of this gas to silicon dioxide, and thermal fusion of the resulting dust (although there are alternative
processes). This results in a transparent glass with an ultra-high purity and improved optical transmission in the deep ultraviolet. One common method
involves adding silicon tetrachloride to a hydrogen-oxygen flame, however use of this precursor results in environmentally unfriendly by-products
including chlorine and hydrochloric acid. To eliminate these by-products, new processes have been developed using an alternative feedstock, which has
also resulted in a higher purity fused silica with further improved deep ultraviolet transmission."
http://www.websters-online-dictionary.org/definitions/Fused+...
http://www.azom.com/Details.asp?ArticleID=263
[Edited on 18-2-2011 by Morgan]
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Morgan
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"Documented attempts to make rubies date to the experiments of Marc A. Gaudin, a French chemist who produced some synthetic rubies beginning in 1837.
They were not of any value as gems, however, because they became opaque as they cooled. After 30 years of experimenting he gave up, admitting defeat
in the published notes of his final ruby experiments."
"There are several processes used to create synthetic rubies. Verneuil's flame fusion and Czochralski's crystal pulling are the most commonly used
melt techniques, while flux growth and hydrothermal growth are the most popular versions of solution processes."
http://www.madehow.com/Volume-4/Synthetic-Ruby.html
[Edited on 20-2-2011 by Morgan]
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Sedit
International Hazard
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Its time to get down to business folks, materials here, skills have been brought back to par and im as ready as ever, so I have a few questions to ask
before going on to ensure the quality is worth being marketed in anyway.
First off is the big one IMO, what would be the best thickness for crucibles and ceramic tubing? The thinner the better since it helps avoid thermal
shock and cracking yet you also would want there to be strength so its a balancing act between the two. Does anyone have a commercial crucible,
preferably broken so that they could measure the thickness. I need to know this because it will determine the thickness of the slip measured with a
hygrometer and the amount of time the slip sits in the molds. Working with these two factors I could with ease reproduce constant values for the
thickness of the ware.
Second of all, aside from crucibles and test tube/tubing what other specialty items should I start designing molds for? Funnels is a no brainer for me
because I want some for myself yet I would like other suggestions as well.
Thanks for your imput
~Sedit
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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