organicchemist25
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best or recommended vacuum gauge/manometer?
I had a cheap vacuum gauge that quit working (internal parts must be seizing up) and I did buy a digital (used) manometer. I am not sure if it is
correct or calibrated correctly, or even how to for that matter.
So, I am looking to get another one. Anyone have some recommendations?
I have been searching for McLeod and other various manometers. Im not real pressed for cost, but 200-300 is max I would like to spend.
I want a nice one (of any highly recommended one) that will last and be easy to calibrate if needed.
Thanks
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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Got some mercury and a glass tube?
http://www.mrbigler.com/moodle/mod/lesson/view.php?id=1942
[Edited on 12-3-2015 by Bert]
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organicchemist25
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I have a little bit. I'd say approximately 2-3 ml. I could probably get some more. How much are you thinking I would need?
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Bert
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Total volume depends on tube Dia., but enough to fill about 100 cm of vertical tube. Look at the link or google "mercury manometer" for diagrams-
Or if you've got lots of space, water works. You will need about 10 meters of height with a water filled tube, though. Mercury density allows for a
bench top tool.
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Sulaiman
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What vacuum range do you want to measure?
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Magpie
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I use (and like) a Bennert manometer. It uses mercury.
The single most important condition for a successful synthesis is good mixing - Nicodem
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organicchemist25
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I really do not see myself going below 0 mmHg/torr
Then again, I have not came across a need yet to go into the negative range...but when I do, Ill upgrade the equipment. I have a pump capable of
approximately getting down to 20-30 torr. I have a Dewar cold trap setup for the vacuum.
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organicchemist25
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Does the mercury come with it? or would I need to get some Hg and fill it myself?
Any calibrating required, Magpie?
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organicchemist25
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I appreciate everyone's responses 
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Magpie
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They are usually sold without mercury. I bought mine used off eBay. I filled it with mercury myself. It's a little tricky as the tube must be fully
evacuated before pouring in the mercury.
As for calibration it really shouldn't need it if you've fully evacuated the tube to P=0 mmHg before filling. I did check mine against an Inficon
Pilot Plus vacuum gauge.
[Edited on 13-3-2015 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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