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Jimmymajesty
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The smell of AA is etheral in the first 2-3 second then the pleasant light smell turns into strongly acetic, and irritates the eyes and all your
mucous membrane like hell.. I really fucked up the first time I smelled it
If you pour a little water(cold) + AA into a test tube then shook it, the mix quickly separates, my experiance is that the AA will be the upper layer
in spite of the fact that its density is higher than that of water.
Also you can light it with a flame, while glacial acetic does not burn.
Another test is to boil it with ethyl alcohol, but do not forget to add a few drops of H2SO4 or you will get nothig.
If you ask me, the kete method beat the shit outta all the other methods mentioned here.. I mean.. It is nice to filter extract heat chlorinate
fractionate etc.. to get a few ml of AA and get closer to chemistry, but if you want a decent quantity, ketene is the way to go.
I made pure/colourless ~95% AA by the ketene method several times ~250ml/run. One run takes me about 6 hours. and the yield was always more than 80%.
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Magpie
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Quote: Originally posted by Jimmymajesty  |
I made pure/colourless ~95% AA by the ketene method several times ~250ml/run. One run takes me about 6 hours. and the yield was always more than 80%.
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Jimmy could you please provide the particulars for the procedure you used to do this. I have tried this several times without success. My tube
furnace was either run wo/packing or with broken pieces of porcelain. I followed the procedure in OrgSyn.
http://www.orgsyn.org/orgsyn/default.asp?formgroup=basenpe_f...
up&dataaction=db&dbname=orgsyn
[Edited on 3-6-2010 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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Jimmymajesty
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I will take a photo from the ketene generator when I got back my cam.. I am going to put a spline or something next to it for you to be able to take
its measures by the picture. But easier to say that I followed the organic reactions vol 3 that is in the public library.
I could not follow all the instructions for obvious reasons, for example I cannot afford platinum wire.. But the lamp works well, and thats the point.
The main issue with the tube furnace method is the reflux, I use a two litre RBFL as a reboiler, and during the 6 hours, if I had to make a guess, I
reflux the 1 litre acetone a hundred times. This cannot be done in case of tube furnaces.. I think.. but I never tried tube furnaces.
BTW carbonisation is not that big of an issue, after two runs the kanthal wire was still ok, and the reboiled acetone had only a yellow tint, also it
can be reboiled to get rid of conjugated olefines which I think the main impurities in acetone after a couple of runs.
If you are seriously planning to bulid a lamp, I can advice you how to improve you filament and also plastic materials which are resist to ketene, but
a lot of plastics resist to it.. actually all of the plastics I used till now resisted to ketene
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Jimmymajesty
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See attachment for photos.
The tungsten rods were purchased from welding shop, their diamater=1mm
It was difficult make the upper part of the device for even an experienced glass blower.
And when I showed to him the original drawing, he said at first that theres no way that he could make it, so we discussed the possibilies, again, it
works well and only costed me about 30 dollars not counting the tungsten rods which costed about 1 dollar each.
I can highly recommend to anyone who wants to make ketene or acetic anhydride to make this device, it was a first run success type synthesis, while
with acetaldehyde I sucked alot.
P.S. Magpie seeing the apparatus you have, you should really give the lamp a try! I mean quartz tube with grounded joints etc... eh!
Attachment: lamp1.rar (1.1MB)
This file has been downloaded 1270 times
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Magpie
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| Quote: Originally posted by Jimmymajesty |
P.S. Magpie seeing the apparatus you have, you should really give the lamp a try! I mean quartz tube with grounded joints etc... eh! |
Thanks Jimmy for the photo. It looks like that scale is about 13 cm long?
That's an impressive looking piece of glassware. Unfortunately I don't have a local glassblower that will help me. We have one but he has his head
up his ass. He'll only work for businesses or educational institutions. 
I can't believe that you got that put together for only $30. You must not live in any "Western" country. That would be at least $100 where I live.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Jimmymajesty
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The AA will sink to the bottom in cold water too.. sorry for my misleading information above. I checked it.
I also tried out the reaction with benzamide, I added AA to benzamide, as usually nothing happened, then a few drops of H2SO4 and heat, and the
content of the test tube immediately turned into intense red, almost black.
Magpie yes 13cm long.
Here in my country.. In the heart of Europe I know at least two glass blower that
would be happy to make such kind of useless stuff for almost nothing, Iam suprised that you do not have any..
It would be nice If you could make a similar lamp and calibrate it.. for reflux ratio, different pretreatement of the filament etc, and compare the
resulsts with mine.
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hypnos
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Thanx not_important,,, much appreciated information...as you say,,not too good to be true.....just a "little tricky!!!"
[Edited on 6-6-2010 by hypnos]
[Edited on 6-6-2010 by hypnos]
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peach
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Jimmy is becoming my new hero with gear like that.
Have you considered plating the tungsten? I'm sure it can be done, not only from the reactivity of tungsten but I've seen it online. I wouldn't be
surprized if it worked out cheaper to do it yourself, or take it to a jewelery store.
Now I'm going hunting to see if I can find anymore pictures of your glass.
I'd love to take up scientific glassblowing. I'm sure it's tricky. But I doubt it's beyond me if TIG welding, diy'ing a furnace and casting metal
isn't.
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Jimmymajesty
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I do not really understand you with your tungsten plating thing, you have to buy pure tungsten, molybdenum or platinum, other metals cannot be wetted
by melted glass. tungsten is easy to get and cheap while the others are not.
I am also prefer to see pictures than imagine the glassware by dud descriptions, so...
The second picture is of the ice cube maker that is necessary to prevent acetone from boiling over, It keeps the cooling water temp @ ~6-10°C.
Attachment: lamp in operation.doc (1.6MB)
This file has been downloaded 1114 times
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densest
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@peach - scientific glassblowing is fun, but it takes a -lot- of practice. The equipment required depends on the size & complexity of what you
want... an annealer big enough to hold the completed piece is essential. Assembling pieces isn't that hard. Freehand creation of coils, globes, etc.
takes much practice and specialized torches. You can get started with a propane-oxygen torch, a low temperature ceramic kiln with a ramp-hold
temperature controller, and a set of crossed polarizers to see where the strains are. There are books & videos.
$30 for Jimmymajesty's piece is unbelievably inexpensive. Paying 100 euros to get it sent to the US would still be very inexpensive!
@Jimmymajesty - did your glassblower fuse the tungsten directly to ordinary borosilicate glass (pyrex, kimax, etc) or did he first bond the tungsten
to a special glass which he then fused to the borosilicate tubes?
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Jimmymajesty
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Densest is right, a kiln is necessary, otherwise the glassware will crack on cooling, I also cracked some glassware even after annealing, especially
the grounded glass joints the weak points.
My glassblower only work with pyrex, i.e. borosilicate, and uses acetylene-oxygen torch.
To make an electrode you have to heat the tungsten rod first, then melt a glass bead (also pyrex) and rub it on the surface of the rod, it will cling
to it, then you can melt it into a tube with grounded glass joint.
The glassblower knows me well, but sent me to hell when I asked him to make spare electrodes.. so everyone draw their own conclusion
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watson.fawkes
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| Quote: Originally posted by Jimmymajesty | My glassblower only work with pyrex, i.e. borosilicate, and uses acetylene-oxygen torch.
To make an electrode you have to heat the tungsten rod first, then melt a glass bead (also pyrex) and rub it on the surface of the rod, it will cling
to it, then you can melt it into a tube with grounded glass joint. |
For the beading technique you describe,
the initial heating of the tungsten rod should be done with an oxidizing flame. The oxide lowers the surface tension of the tungsten-glass contact
layer and affords a more reliable seal.
It's possible that the beading glass wasn't the same exact glass used for the body of the device. Schott 8448 is specifically designed for sealing
Duran (et al.) to tungsten. It has a coefficient of expansion (3.8) which is about at the geometric mean between borosilicate (3.0-3.35) and
tungsten (4.6) (All coefficients are in μ/K) This is a borosilicate-like glass, with some other ingredients (unknown to me at this time) added
to change the expansion coefficient. For example, Corning 3320 (evidently no longer in melt; it's not on their web site) was doped with uranium. I'd
be interested in knowing if your glassblower was using a sealing glass or just beading with the same material as the body.
For those few doing this themselves, the common tungsten welding rods in the US are 0.125". According to my reference, these have a safe
current-carrying capacity of 50A before overheating of the glass is a problem. This is for a single-lead device; for a pair of closely-space leads (as
for a heater) this should be derated.
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peach
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Jimmy, I mean plating the tungsten with platinum, which could be done after the electrode was in the glass.
$30 is ridiculously cheap for something like that! Although, it depends what $30 means where you are I guess. If it's the US, it's not a lot.
I've also heard about the benefits of forming the oxide when producing hermetic seals with glass. I was heavily into Sam's Laser FAQ when I was about
11 (or something around that age) and they'd always be going on about glass work - amongst other strange (and very interesting to me) things, like
high vacuum or high voltage gear.
I have a really nice oxy/acetylene torch that I bought when I was about 14, with all my pocket money. The whole kit cost something like $600 at the
time. That was a lot of birthday and christmas gifts saved up over years. I've heard about using polarized filters for strain observation and
annealing by hand, but even with the filters I wouldn't trust the latter.
So the main thing stopping me from having a go is the kiln. I could build one, as I've also spent years reading around casting metals (like iron) and
have built a high temperature furnace before; the annealing temperatures for glass would be eeeeeasy (if you don't believe me, try cutting near pure
alumina insulation first  ). But I don't have anywhere to put one at the moment.
Just as I was feeling all sad about that, I had a brainwave. How's about blowing hot air through the glass with a modified heat gun? The glass could
be wrapped in glass wool for insulation and the cooling period set by PWM of the coil. Or fill the glass with something that'll conduct heat, insert
some nichrome wire and wrap in wool?
Either way, I doubt the owners of my current home would appreciate me firing up acetylene fueled welding gear at the moment. 
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Jimmymajesty
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Peach I see now.. but plating is not necessary since tungsten is inert enough, for such applications, even if the starting acetone contains some
water, the forming acetic acid would not attack the tungsten (I think, I always use dry acetone though)
The glassblower did not used another type of glass to wet the electode, he showed some electrodes to me which was sold pre-wetted with some other type
of glass, but he rather made new ones on his own instead of using the ones at hand, I do not know why.. maybe he likes challenge
Tungsten rod of 1mm diameter far enough for a lamp as far as current is concerned, but take care not to break it.. tungsten is rather fragile.
After the glasswork there was a rather thick oxide layer on the tungsten which was as solid as glass, also take care not to break the rod while you
are removing it.
I know 30 dollar is not much, maybe I should ask him to make some for sale.. pity that there would not be a big market for them in my country
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densest
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@watson.fawkes - Schott 8448? Hmmmm.... thanks!
@peach - working borosilicate requires really good ventilation. Outdoors is best if you don't have a powerful exhaust fan. Used ceramic kilns are
often sold by people who get bored with making pots. You could put it on a rolling cart. Again, outdoors is good. Use propane or natural gas not
acetylene in the torch. Acetylene has too much carbon in it. And protect your eyes!!! Didymium glasses are not sufficient - they don't stop
ultraviolet & infrared well. Use glasses designed for borosilicate work.
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watson.fawkes
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Here's the data sheet, attached. Schott also makes other
sealing glasses for Kovar and other materials used in vacuum gear. The Schott web site has a selector application (in Flash, unfortunately, so direct
linking isn't worth it) for browsing their materials. Warning: the CoE for 8448 in that app is listed at 3.08 (which would be absurd for a W-seal),
not the 3.8 in the data sheet.
Attachment: Glass_8448_datasheet_english.pdf (35kB)
This file has been downloaded 761 times
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peach
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densest
You can't use acetylene even with the flame finely tuned? I know what you mean about carbon, just lighting the torch would have cobwebs all over the
roof. A trick welders use is to purposefully set the flame carbonizing, deposit carbon on a piece of scrap and then turn the oxygen up until it'll
remove the carbon. I have a pair of funky gas welding goggles which I'm sure would be fine for glass work, they're well shaded for UV and make the
world an attractive lime green tone. I've seen those kilns too. A lot of them got thrown out by schools after healthy and safety said no to kids being
involved with fire.
watson
I believe molybdenum is also used for hermetic glass seals.
jimmy
I would ask the guy if he's interested in selling some more of his products. I'd be interested in buying some of them.
All you need is a website and cheap shipping. Buy a stack of cardboard boxes and pack them full of scrumpled up newspaper. If scumpled correctly, it
works just as well as bubble or peanut packing and is basically free. Use the economy courier options, like FedEx domestic. It's slower, but a lot
cheaper. And I doubt any of the customers would urgently need the glass.
I suspect you'd probably get a few orders from this site, and others if we spread it around.
I think a lot of us tend to pay the prices for named glass for fear of how well it's been blown. I've received a condenser (a really cheap one
probably made in a sweat shop in India or China) that had bubbles and a crack already in the glass, from new. I had it replaced and the second had
bubbles. I don't criticize sweatshops too much though, because you can't expect excellence from overworked, underpaid slave labor. If he can blown
glass well and is annealing it, and you can vouch for him with glass like the lamp, he'd probably get some good business.
He'd need to keep the prices lower than in the US and other parts of Europe, or it'd be easier to buy Quickfit / Corning glass. I'd recommend he also
offers US and European tapers.
It wouldn't be at all hard to put together a quick website. If you ask, the moderators might even let you sell it through here.
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watson.fawkes
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You can, but it's not really about unburned
carbon. The thing to remember is that CO2 is reactive, not inert, at flame temperatures. Apropos of this, the standard flame for working silica glass
(more-or-less pure SiO2) is an oxy-hydrogen flame. Oxy-acetylene is hotter, which would otherwise be good for the very high heat required for silica,
but the carbon contamination is evidently enough of a problem in practice that acetylene isn't much used. I believe (although I'm not certain) that
the problem is SiC formation, which isn't soluble in the glass, and that SiC inclusions act as origins for crack propagation, weakening the glass.
This is less of an issue with borosilicate, since you don't use such a high temperature, but then there's a new problem of lowering the flame
temperature (using oxy-air-acetylene, as one way), or broadening the flame front, or being very careful to avoid point over-heating.
In addition, propane is significantly cheaper per unit heat than acetylene. For example, in scrap steel yards, where they need to cut long beams into
pieces for transport and processing, oxy-propane is the norm, as propane gets the steel plenty hot enough to cut with oxygen.
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Jimmymajesty
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Peach apart from my total inexperience in selling things, it would not be a bad idea after all. Selling glassware is not illegal, isnt it?
We should name the ketene lamp something else, I mean when I hear ketene immediately acetic andhydryde.. drugs and explosives springs to mind.. rather
than amateur experiments. It should be noted however that it can open a new world for the home chemist, you can study a lot of catalytic reactions
with it, e.g. dehydrogenating cyclohexane to benzene, or pyrolyse lighter hydrocarbons to aromatics, just to name some.
I am gona ask the glassblower when I meet him next time, if he made some spare lamps, should the need arise.
It would be nice to see other chem enthusiasts works, in pioneering home pyrolysis, I have not got much time to make experiments at the moment.. I
never had though
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mr.crow
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Pyrolysis Lamp I would buy one.
Maybe some things could be simplified to make it easier/cheaper to make.
Double, double toil and trouble; Fire burn, and caldron bubble
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peach
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Watson
Thanks for the explanation, things like carbon are also incredibly important with steels, where you'll get interstitial carbon and cotrell atmospheres
that either help arrest crack from propagating or initiate them when it's present in amounts large enough to form brittle crystals. Methods of
treating steels rely on the distribution of things like carbon, e.g. solution treatment refers to putting them into a solution like state.
I've seen hydrogen generators before for welding, places like Rio Grande sell them for jewelers. Or there are welding sized ones as well. I actually
swapped my acetylene tank for a propane at one point, realizing it was so much cheaper. It does work for cutting, but it also becomes a pain in the
ass waiting for things to heat up, there's a very tangible difference in the speed between the two if you're using similar nozzle sizes.
One exciting fact I know about hydrogen is that 'sniffing' cylinders of it (knocking the valve open to clear the nozzle) can ignite the gas,
apparently.
Jimmy
Don't worry about that. Even if you post one to a country were it is illegal, the most that'll happen is you'll get complained at by their customs
officers and told not to send anymore. There's no way you'd be extradited and jailed for posting an everyday piece of glassware; e.g. not a 12 liter,
multinecked flask.
I'd call it a reactor lamp, catalysis lamp, catalysis reactor, etc. Or 'Jimmy'. It looks a bit like a Soxhlet extractor. I'd talk to him about the
electrodes in particular. You mentioned he was getting annoyed about making more them, so ask him what was difficult and maybe one of us could suggest
a something to make it easier, so he can produce them without having to put the price up.
As for selling things, it's easy now. There are a ton of sites that basically build your shop for you. I might be able to help with that if he wants
to go ahead.
[Edited on 2-7-2010 by peach]
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densest
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@watson.fawkes - Schott has sent me to a fabricator. They don't sell in less than case or melt quantities which is not at all surprising. They do say
that 8448 is very expensive. It sounds like it's about 10x - 20x borosilicate prices, which isn't surprising either, and if one only needs a cm or two
per joint, 1-2m of small tubing goes a very long way. $3000 or so for a box of it is a bit much - I wouldn't use that much in several lifetimes,
though I'd be willing to retail it for a suitable markup....
If I find an inexpensive source of graded seals for tungsten-to-borosilicate connections I'll be sure to mention it. A reasonably simple
capacitor discharge welder would be sufficient to attach various interesting contraptions to such an electrode.
Every maker of graded seals I've found says "call for quote" = you can't afford it, you peasant... I hate "call for quote" - it usually means a
company who wants to rape you for everything you have. Or the company has so much overhead they can't make any money on orders less than $10,000. Ugh.
No wonder the US doesn't have any manufacturing left.
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watson.fawkes
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| Quote: Originally posted by densest | | @watson.fawkes - Schott has sent me to a fabricator. They don't sell in less than case or melt quantities which is not at all surprising. They do say
that 8448 is very expensive. It sounds like it's about 10x - 20x borosilicate prices, which isn't surprising either, and if one only needs a cm or two
per joint, 1-2m of small tubing goes a very long way. $3000 or so for a box of it is a bit much - I wouldn't use that much in several lifetimes,
though I'd be willing to retail it for a suitable markup.... |
Give Wale Apparatus a call. It's not listed on their web site, but they seem to the last general-purpose scientific glass supplier standing. There are
a number of others (like Pegasus and Ace), but they've all specialized in some way. Wale should at least be able to steer you to someone that's
willing to deal with an odd lot order.
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peach
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| Quote: Originally posted by densest | "call for quote" = you can't afford it, you peasant... I hate "call for quote" - it usually means a company who wants to rape you for everything you
have.
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Ha ha ha, yep. I've tried emailing a lot of the custom blowers and they don't even bother replying. Fine. Fuck them. I'll spend all the hundreds
elsewhere whilst their art dies.
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Jimmymajesty
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I have not been at him lately, and do not really know when I will.
Seeing that the acetic anhydride thread turned into a meeting place of glass blowers (and wannabees Why not make the whole upper part of a teflon block? This was my original idea in case of the glassblower could not
make it out of glass. I would drill two small hole into the block which would be previously forged to fit in the large grounded female joint, then I
would drill an another for a glass rod with a screwed end, it should work, teflon is smiling up to 450°C IIRC, keep the reflux high and It will keep
smiling even at higher filament temps.
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