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Pyro
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[*] posted on 18-8-2012 at 11:58
23 DURAN bottles


hi,
I just bought 23 duran bottles. these ones to be precise.
23 for 75 EUR. I have been looking for a good price on these for ages. they got me on shipping though.
but now i got 23 nice bottles oooh...
what do you think?

[Edited on 18-8-2012 by Pyro]




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Dr.Bob
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[*] posted on 19-8-2012 at 14:05


That is a great price. They are quite heavy each, so shipping should be a good bit.
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Pyro
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[*] posted on 19-8-2012 at 14:13


yeah, 35 eur! from germany to belgium, but now i finally have some proper bottles.
they are about 1/2 of the normal price of second hand ones.
Why do they actually cost so much?




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Lambda-Eyde
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[*] posted on 19-8-2012 at 15:18


Great price for 23 Duran bottles? Yes. Great price for 23 bottles? Only barely. I bought 10 500 mL Simax bottles, the same design as the Duran ones, for ~25 € or so. The only difference I can think of is the brand, I'm not picky about glass quality when it comes to storage bottles, RBFs are something else. Now, if those bottles had the red caps, then it would be a really nice find!



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Pyro
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[*] posted on 19-8-2012 at 15:28


red caps? whats with red caps?
I just have a weak spot for DURAN. then you were lucky, as new simax costs more than what you paid for them




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Lambda-Eyde
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[*] posted on 19-8-2012 at 15:56


The red caps (melamine with ETFE liners IIRC) are much more resistant than the blue PP ones. I use my red caps for bromine and nitric acid among other things. The blue ones can't handle strong acids, strong oxidizers or organic solvents, but the red ones will. Baffcat on eBay stocks the red ones, both GL32 and GL45.

I bought my Simax bottles from a reputed vendor, not from eBay or second hand. They weren't on sale, either. I must admit I have a weak spot for Duran myself (as well as Pyrex), but sadly I only have a few RBFs that are Duran made.




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Pyro
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[*] posted on 19-8-2012 at 17:27


dammit! i've stored nitric acid in my 1l brown bottle, no wonder the cap turned white on the inside.
how does teflon do vs Br2? the caps of my 2,5L are teflon lined.




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[*] posted on 19-8-2012 at 18:21


Teflon is much better. The red caps are normally lined with Teflon. Those caps are pricey. But I have found that the liners tend to fall out sometimes if the cap is heated. The red caps are ment for use in an autoclave at temps above 140 C. The blue caps are only good to about 140C, but handle many organic solvents, dilute acids and water solns.
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[*] posted on 19-8-2012 at 18:45


is it possible to buy the teflon inserts? as half of my caps are missing them.
but back to these bottles: why are they soo expensive? yeah, i get the borosilicae glass etc. but i can buy a beaker (DURAN) for about half the price of a bottle.




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[*] posted on 19-8-2012 at 23:25


The blue PP caps aren't supposed to have inserts. They are expensive because glass threads are expensive, plus the ones you bought have retrace codes (not that I really understand why they're worth paying double price for). As already mentioned, the Duran logo on them doesn't help the price either. If you want to find out what you can store in bottles with blue caps, google a plastic resistance chart and look for PP (polypropylene). I know I have already linked to or uploaded one specific to PP in a similar discussion earlier. If you search you may find it.

Teflon is chemically inert to most chemicals known, but is permeable to a few chemicals and may slightly swell. It holds up well to bromine.




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[*] posted on 20-8-2012 at 04:34


Another reason why these bottles are so expensive is that they may be heated to 140 C without the risk of cracking. I once did that with a simple glass jar and while doing so, it cracked while it was heated. Normal glass of that thickness has uneven coefficient of expansion and some places may expand more than other places when heated. This leads to strong internal forces, which eventually may lead to breaking of the glass. Ordinary household jars almost certainly don't withstand heating to 140 C.

I have yet another type of caps for my bottles. Have a look at the wikipedia page for bromine, it shows my bottle of bromine with a blue cap, which has a red rim. Inside there is a thick grey teflon liner, which keeps the bottle perfectly well. The cap is not corroded at all and no bromine escapes the bottle. On the wiki page for nitric acid you see a picture of another bottle, which holds fuming yellow nitric acid and this also keeps well. With fuming nitric acid, however, there is a slight leaking of HNO3 through the cap. It can be neglected in terms of loss of acid (even over several years, the liquid level in the bottle has not lowered noticeably), but it leads to a 'frost' on nearby bottles and on the bottle itself. After a month or so of storoage, there is a clearly visible 'frost' on the bottle and on bottles nearby.

These caps unfortunately are very expensive. IIRC, for ten of these caps you have to pay EUR 70 or something like that, excluding shipping and handling.




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[*] posted on 20-8-2012 at 07:19


cool caps! i was talking about my 70% in a 1l bottle.
see:masses of brown glass bottles for the type I mean.
all the caps there should have Teflon inserts, but many are missing. most of the big dark blue caps still have the Teflon inserts, but the other ones are missing all of them.
the dark blue ones look exactly like the ones Aldrich uses for Br2. that's where I am planning to store my Br2 when my sodium bromide finally arrives.




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[*] posted on 20-8-2012 at 07:51


Quote: Originally posted by woelen  
These caps unfortunately are very expensive. IIRC, for ten of these caps you have to pay EUR 70 or something like that, excluding shipping and handling.
They're expensive because the material is expensive. I can't speak to exactly the manufacturing processes used for the bottles in question, but I can point to a homebrew version made out of Teflon rod stock. McMaster-Carr sells it (a US industrial supplier); just search for "Teflon rod stock". A typical wide-mouth storage bottle has a 2" OD against which a simple disk liner would seat. (I have some in exactly this dimension; I checked.) One foot of 2" Teflon rod stock is (as of today) just shy of 100 USD. Look at the prices for other dimensions; the bulk of the price just goes by volume and the per-unit premium is fairly small here.

If you had just the right kind of guillotine knife, so that you could cut slices off without waste, say at 1/8" (~ 3mm), each of these slices has a raw material cost of about $1. That's before all the other components of such a cap. Raw materials for good run as a rule of thumb 30% of the final product cost, although I suspect the markup is higher in this market. If you want a better seal, one that seals both on the top of the bottle and the inner surface of the opening, you need 2x - 3x of the PTFE material, and also more machining and/or molding cost. It's some easy lathe work to turn such liners; it's an ideal kind of project for a small CNC lathe.

The upshot is that you can make these liners cheaper than buying them, but only with the right kind of shop. Consider them a bargain if you don't already have the tooling
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[*] posted on 21-8-2012 at 11:02


does anyone know what purple caps are? i just bought 10 VWR media bottles for 35 dollars!







[Edited on 21-8-2012 by TheChemINC]
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