Gooferking Science
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Separatory Funnel O-Rings
I recently lost an O-Ring for my separatory funnel’s stopcock down the drain. I am looking to buy a replacement, but I am unsure what type of O-Ring
will provide the chemical resistance that is necessary. It needs to be able to withstand many organic solvents as well as acidic and basic solutions.
Will Buna-N or Viton be sufficient? Or does it need to be something more substantial like PTFE or Chemraz?
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Magpie
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I would try the O-rings from Ace Hardware. I think they are made of Viton.
The single most important condition for a successful synthesis is good mixing - Nicodem
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JJay
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I also think Viton would work well. It is almost as resistant to chemicals and temperature extremes as PTFE.
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Texium
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At work, I have nitrile (NBR), HNBR, and Viton O-rings. They all work fine, but the HNBR and Viton seem to be more durable for long term use than the
nitrile ones, which begin to wear out over time.
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XeonTheMGPony
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Viton is used in most HVAC gear, where it is exposed to some pretty nasty conditions.
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NEMO-Chemistry
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I been using these with vac high temp grease. They are on ebay and ALL 4 boxs were sold together for £4
https://www.ebay.co.uk/itm/419pc-Rubber-O-Rings-Tap-Washers-...
![20180113_032951[1].png - 1.1MB](http://www.sciencemadness.org/talk/files.php?pid=503649&aid=64057) ![20180113_033026_-_Copy[1].png - 1.2MB](http://www.sciencemadness.org/talk/files.php?pid=503649&aid=64059)
[Edited on 13-1-2018 by NEMO-Chemistry]
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Dr.Bob
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Great find Nemo, I paid a lot for a box of them years ago. But I always run out of the smaller ones for stopcocks whenever I have an assortment.
Viton is fine for most chemicals, the O-ring should not see much solvent if the stopcock does not leak.
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PiledhigherandDeeper
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Quote: Originally posted by Dr.Bob  | | Great find Nemo, I paid a lot for a box of them years ago. But I always run out of the smaller ones for stopcocks whenever I have an assortment.
Viton is fine for most chemicals, the O-ring should not see much solvent if the stopcock does not leak. |
Dr. Bob (and ALCON)
https://www.harborfreight.com/180-piece-viton-o-ring-kit-675...
Picked these up for 10 bucks at HF yesterday. Granted you get 5-10 of numerous sizes, the price is right for me. A 50 pack of one size is about the
same price at McMaster Carr; I suppose it depends on how many of one size you go through.
Magpie,
Thanks for the tip about Ace. I am really developing a strong love for Ace Hardware and how they provide under the radar items for hobbyists.
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Magpie
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You're welcome. One member said that Ace is a chemical supplier masquerading as a hardware store.
The single most important condition for a successful synthesis is good mixing - Nicodem
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NEMO-Chemistry
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We have a crap hardware store! But seriously from a UK perspective, i can honestly say the above quote could be nearer the truth than you think.
Regulations would be less, plus its easy to justify alot of chems for a hardware/DIY type use. But set a Chemical company up and try and sell hardware
would not be so easy.
Your equiv to our SIC numbers would make it hard for a chem company to sell Hardware, but the SIC numbers are not difficult to switch around so a
hardware company could sell alot of chems.
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PirateDocBrown
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A while ago, California had a restriction on sale of MEK, I'm assuming for air quality reasons. So, WM Barr, the main maker of it for consumer
purposes, came out with "MEK substitute" for a short time. It was ethyl acetate, in inexpensive gallon quantities. Later, the restriction was
reversed, and Barr went back to MEK and discontinued the substitute.
But my local ACE has both on the shelves! Gotta love it.
Phlogiston manufacturer/supplier.
For all your phlogiston needs.
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