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Author: Subject: Question about Bomex equipment
bereal511
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[*] posted on 9-12-2005 at 23:05
Question about Bomex equipment


I recently procured a shipment of laboratory glassware, and I was surprised to find that the label said Bomex on the glassware. From where I ordered it from, the description said that it would be of the "Pyrex type." I'm pretty inexperience with lab glass, but from what I've learned on this forum, Bomex is the worse glassware of them all. So I'm a bit concerned as to what I should do. Should I complain and get a full refund or stick it through and use the glassware for now? I'm not sure if it would be worth the time and effort to return all of the glassware back, and having no experience with glassware, I don't know the quality of Bomex in the field of experimentation. The whole set costed $118, and I planned to use it for low temperature (anywhere from 200 C - 300 C) chemistry.



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Darkblade48
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[*] posted on 9-12-2005 at 23:22


IMO, Bomex is the most unreliable glassware of all (cheap made in China stuff). I'm currently using Pyrex/Kimax stuff (made in US) and they are pretty durable, I haven't had anything break (other than dropping a 400 mL beaker from 4 feet up in the air onto cement....accidently, I swear!)

If possible, I would check to make sure that the website says "Pyrex Type" and not "Pyrex". I would imagine that the company could find a loophole around your complaint because they used "Pyrex Type" (what exactly is Pyrex "type"? Pyrex is just a name brand attached to glass. Bomex is glass. They could argue that they sent you Pyrex "glass")

As for your "low temperature" chemistry, 200 - 300 C is not something I think that Bomex would stand up to too well. In fact, I think the extreme temperature changes and shock would cause the glass to crack quite quickly.
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[*] posted on 9-12-2005 at 23:42


Well, Bomex is still borosilicate glass, so it can handle some heat, but I would not use it for heating over, say 150, and never let it be exposed to thermal stress. Bomex is infact 'pyrex type' in that they are both borosilicate, so I do not think your complaint would work to get pyrex. If you just plan on heating aqueous solutions, you should be fine, Bomex is not THAT bad. We just badmouth it all the time because it is definatly not as good as pyrex and kimax, and does break more often, and in my experiance the glass is much thinner than pyrex, and often contains bubbles within the glass.

What type of glassware did you get and what sort of experiments do you plan to do? That will ultimatly determine whether bomex will work for you.

I have mostly pyrex/kimax but one or two beakers are bomex, and most of my grad cylinders are actually bomex, but those do not get heated. I have wanted to get a few pieces of that schott-duran, just to see for myself if it is as good as rumoured.

[Edited on 10-12-2005 by rogue chemist]




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bereal511
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[*] posted on 10-12-2005 at 07:24


Ah drat, well, thanks for clearing that up. At least now I won't look like an idiot :D.

Well, I bought a four beakers and flasks along with twelve test tubes, six eye droppers, two graduated cylinders, a glass pipette, and a glass funnel. I was planning on working with acids, concentrating and reacting them. I also wanted to do some experiments with metal salts to use in an electrolytic cell.




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[*] posted on 10-12-2005 at 08:01


With the acids I would be very careful. A spill of a concentrated hot acid is nasty, very nasty. Breaking glassware is not fun at all with the hot concentrated acid in it. Of course, with the correct precautions and using not too large quantities, you should be fine. The concentration of the acids probably won't rise the temperature much above 150 C. The experiments with the electrolytic cell and the metal salts are OK.



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neutrino
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[*] posted on 10-12-2005 at 08:31


You got that for $112? I'm sorry, but you got seriously ripped off. You need a new supplier. A number have been described around here, just search.
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bereal511
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[*] posted on 10-12-2005 at 08:41


Oh, it included other things besides the glassware. I think the glassware by itself was $55. Not sure if that helps though :(.



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[*] posted on 10-12-2005 at 09:57


Quote:
Originally posted by bereal511
Oh, it included other things besides the glassware. I think the glassware by itself was $55. Not sure if that helps though :(.

Well, I guess it depends on their size (i.e. 250 mL vs. 1000 mL?)

If you bought "standard" equipment (250 mL beakers, flasks, etc), then you probably still could have gone down a bit lower.
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bereal511
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[*] posted on 10-12-2005 at 11:02


It was pretty much standard equipment. The beakers and flask ranged 500 - 50 mL. What should have been the ideal price of it had I bought it from another company?



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[*] posted on 10-12-2005 at 11:18


Judge for yourself. Here is the ideal company. Enjoy.
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[*] posted on 10-12-2005 at 13:08


Most of my beakers and erlenmeyers are the bomex type but I haven't had much problems with them. The first beaker I ever bought (400ml one) was bomex and it's still doing just fine and it has gone through a lot of temperature changes and occasional drops on the table. Perhaps it's just some kind of 'better' bomex. :)

Quote:

I have wanted to get a few pieces of that schott-duran, just to see for myself if it is as good as rumoured.


Nearly all my other glass is schott-duran and not one has broken because of rapid temperature changes and few have even survived a drop on the floor so I'd say it's pretty much worth the price. But as I noted, bomex will do just fine for beakers and erlenmeyers.

[Edited on 10.12.2005 by IPN]
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[*] posted on 10-12-2005 at 14:15


I'm a little more cynic about bomex. I poured room temperature water into a hot 2L beaker and it instantly shattered (the bottom fell out). Be careful with this stuff around chemicals, that's all I can say.
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[*] posted on 10-12-2005 at 16:27


I had one bomex beaker, I was evaporating some dillute phosphoric acid on a hot plate when I noticed that the beaker was cracking at the top. above the liquid level, where there shouldn't have been terrible strain, the crack was visibly moving along the beaker over time so I had to change flasks, there wasn't any problem after that.



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[*] posted on 10-12-2005 at 17:11


Quote:
Originally posted by BromicAcid
... the crack was visibly moving along the beaker over time so I had to change flasks, there wasn't any problem after that.

:o You could see the crack moving? That's pretty scary.
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[*] posted on 12-12-2005 at 11:34


Well awhile back I started "testing" any new glass I get, because sometimes If one buys a used or antique piece It probably "tell" what type it is. I simply heat test the "new" glass in the oven or on the burner. I won't use glass without testing it first, and I "retest" pieces that have undergone any "thermal stress". I have had bomex pieces pass and pyrex fail. No matter what type of glass you have at your disposal, heating and cooling should idealy take place gradualy, be patient, don't just crank up the heat on a reaction to try and get it done in a hurry as this usually doesn't give the best results anyway in most cases. Also, if a reaction calls for a "cooling bath" to be present during the reaction, then a person should probably have several baths at varying temps. in order to "quench" the reaction in stages to reduce thermal stress on the glass. It my not be possible to go from "high heat " to an ice bath, One might go from "high heat" to boiling water bath, to room temp. bath, to ice bath. A small tap or hit that would not harm a piece of glass at room temp. could totaly shatter it at high heat. Just handle it with care it is after all glass.



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[*] posted on 12-12-2005 at 12:00


Very true ChemGrl, despite my bomex's spectacular failure (weird how the crack started at the lip) the beaker did manage to survive my normal routine of wear and tear quite well for several months, it was noticeably thinner then my other beakers though, but I also had pyrex beakers thinner then my other pyrex beakers, I guess that is what I get for having so much second hand equiptment from so many generations of chemists. But definatley, heat stress brought on quickly, those thermal shock situations are the worst on glassware, someday I hope that fused silica will fall into the price range of the home chemist, I was looking at a 24/40 RB fused silica flask the other day, 100 ml, it was $90 which was definately one of the better prices I've seen for something like that, considering a 20 ml fused silica test tube from the same people was $24, but it could definately take some thermal stress.



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bereal511
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[*] posted on 12-12-2005 at 17:21


What makes fused silica different from regular glassware?



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BromicAcid
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[*] posted on 12-12-2005 at 17:54


As I often say, fused silica (aka vycor, fused quartz, and others) is the holy grail of glassware. It is a covalent network of silicon and oxygen atoms, there is no flux, nothing like sodium atoms, boron atoms or anything else in there, it is all SiO<sub>2</sub>. Its most incredible property bestowed upon it is rediculous resistance to thermal shock, supposedly you can take a crucible made of fused silica heat it to red heat, and toss it in water and it will not shatter. It's so expensive because the SiO<sub>2</sub> going into it has to be specially purified and finally melted and it has a fairly high melting point, even in an industrial setting.



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[*] posted on 12-12-2005 at 20:24


Actually, white heat. (Personal experience here.)

I believe that the main reason fused silica is so expensive is the very high temperatures needed to melt quartz. High silica glasses require lower temperatures (by about 200*C, IIRC) and these can be reached more cheaply.

A quick note about high silica vs fused silica: quartz and fused silica are 100% SiO<sub>2</sub>. High silica glasses (including Vycor) are 98% SiO<sub>2</sub> and 2% sodium silicates.
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[*] posted on 13-12-2005 at 10:05


Hmm, maybe I am just one backwards fellow, but my expierences have been pretty much the opposite of what is posted here.

I bought a Pyrex set from Fisher many years ago (I know, I paid way too much), and there isnt much left of it now. The flasks in particular would break at the smallest physical thing, for instance I dropped one 50mL flask (half full) no more than two inches into an oil bath and the damn thing shattered. (Both oil and flask were room temp.) Never had a problem with thermal cracking, but then I dont do a whole lot of molten salt/metal type stuff.

On the other hand I bought a 100mL pure quartz crucible with the intention to thermally convert nitrate -> nitrite. The first time I used it I ran out of propane before the nitrate was even half melted, and on cooling the son of a bitch cracked. Does potassium nitrate expand when cooled? It must, although to see this 3mm thick crucible crack under so little strain was a definite disappointment. I wasnt even directly heating it with the propane (asbestos pad) and I had an aluminum foil "chimney" to help with the heating and temperature changes.

On the third hand, I have a 500mL FBF very thick (also 3mm) Bomex flask that I have used for many reactions, including heating it up to convert bisulfate -> pyrosulfate in a direct MAPP gas flame and under vacuum, and I have never had a problem with it. Not to mention I have dropped it once or twice short distances (in the sink, on the labtop) and never had a problem.

It is my opinion that purchasing glassware is just a gamble and that it really is not a permenant investment, i.e. there is a good chance it will break some day, and you will have to buy more eventually.




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[*] posted on 13-12-2005 at 14:47


Very strange. Where did you buy your Pyrex and quartz from?
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[*] posted on 15-12-2005 at 14:41


Well, the pyrex was from fishersci (you know, the "horribly over-priced place that all educational institutions order from"). The quartz was from a reputable company that serves the industrial sector. I'm still in a state of disgust and shock that the crucible broke.

However, I have also come to understand that I am a clumsy oaf, and sometimes just a brainless idiot who doesn't know when to quit. Yesterday I broke a 100mL graduated cylinder (by accidentally banging it against the fridge), a 2L beaker (I was reaching in a cabinet and knocked over that bomex flask I mentioned earlier, which fell onto the beaker which was upside down on some papertowels drying afte being washed... the 500mL bomex is still fine), AND a thermometer (which fell out of a salt/ice bath, hit the floor, and the mercury containing bulb popped off). :mad: :(

Conclusion: I need a new hobby before this one kills me physically and/or financially. Anybody know any good crochet sites? :P




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[*] posted on 16-12-2005 at 05:22


I remeber I had a 600ml Bomex beaker, I was boiling down some Metho/Aspirin to get the ASA for TNP and the fucjking thing cracked, bloody ASA solution all over my hotplate (instantly vaporising the metho). I had to use a razor to get it off. Luckily my dad remebbered he had all thisin the attic:

http://img.photobucket.com/albums/v466/mephistosminion/SANY0...

http://img.photobucket.com/albums/v466/mephistosminion/SANY0...

http://img.photobucket.com/albums/v466/mephistosminion/SANY0...

All pyrex, kinmax and (forgive my heathen spelling) Shott-u-gen-mainz.
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[*] posted on 16-12-2005 at 05:47


HQ glassware is trully great if its not expensive for you but it is not that good if price makes you picky about what you dare to do with it. In may opinion one should mostly buy kind of glassware he is able to replace without much worry. Some high quality flasks are still a must. There are preps that would be otherwise far too dangerous
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[*] posted on 20-12-2005 at 08:07


Quote:
Originally posted by woelen
A spill of a concentrated hot acid is nasty, very nasty.


that coment is worthless without pics, so ill provide them...

http://www.rctparadox.net/gallery/displayimage.php?album=1&a...
http://www.rctparadox.net/gallery/displayimage.php?album=1&a...
http://www.rctparadox.net/gallery/displayimage.php?album=1&a...

be careful with boiling acids. i dropped 150ml of boilign sulfuric about 18". it hit the table and erupted otu of the flask all over myself and the rest fo my lab. melted thru 2 shurts and burnt my chest also.
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