Are there a better stir bar to use? I seem to demagnetize the bar by the end of every run, not sure if they are just cheap or if I’m doing something wrong…
You are heating the stir bar up to the point it loses its magnetism. Almost certainly your mantle is set too high for this process. I did the same to mine at first. Many small mantle manufacturers do not even offer a stir bar option because mantles can easily be set high enough to demagnetize the stir bar.
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Thanks for the input, do you know that temp is, and is there a way to avoid this?
I would only be doing an internet search about degaussing to know because I only had an analog mantle. I would set it on nearly the highest setting. No matter what stir bar I used they all stopped being a magnet in one run. It was way too hot in hindsight but I don’t know the number.
Right on, thanks for pointing me in the right direction. I’ll do some more research and let you know if i can find out anything useful.
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Found this
How it Works
Excessive heat causes atoms to move more rapidly, disturbing the magnetic domains. As the atoms are sped up, the percentage of magnetic domains spinning in the same direction decreases. This lack of cohesion weakens the magnetic force and eventually demagnetizes it entirely.
In contrast, when a magnet is exposed to extreme cold, the atoms slow down so the magnetic domains are aligned and, in turn, strengthened.
Ferromagnetism
The way in which specific materials form permanent magnets or interact strongly with magnets. Most everyday magnets are a product of ferromagnetism.
Paramagnetism
A type of magnetism that occurs only in the presence of an external magnetic field. They are attracted to magnetic fields, but they are not magnetized when the external field is removed. That’s because the atoms spin in random directions; the spins aren’t aligned, and the total magnetization is zero.
Aluminum and oxygen are two examples of materials that are paramagnetic at room temperature.
Curie Temperature
Named for the French physicist Pierre Curie, the Curie Temperature is the temperature at which no magnetic domain can exist because the atoms are too frantic to maintain aligned spins. At this temperature, the ferromagnetic material becomes paramagnetic. Even if you cool the magnet, once it has become demagnetized, it will not become magnetized again. Different magnetic materials have different Curie Temperatures, but the average is about 600 to 800 degrees Celsius.
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You are exceeding the curie temp of the magnet.
You need samarium cobalt stir bars, they have the highest curie temp.http://www.novatech-usa.com/Products/Magnetic-Stir-Bars-and-Accessories/F37102-0138.html?gclid=EAIaIQobChMIwIeekOqy3AIVl6DsCh2_IgSIEAQYASABEgJJmvD_BwE
Work on removing the lowers completly, it seem’s like you are trying to blast past them. What is your best vaccum you can reach with an empty system?
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Please don’t be to critical, I have only had and SPD set up since monday so I am barely a rookie but 10 torr.
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I’m not trying to be critical, I only meant to help. Sorry if I came off strongly.
No you didn’t, I’m my worst critic!!
I am just new is all
If your setup is empty and you can only reach 10 tor you either have a vacuum leak or somethings up with your pump. What model is it? Have you helium leak tested your setup?
I have not helium tested, and need tighter connections for the probe inputs where the kangaroo thermometer and temp probe go into the mantle
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Where are you placing your mantle probe? Are you using a thermowell? Do you have any o-ring style thermometer adapters on your system?
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USA Labs 2l set
O ring style
Read my chart wrong. 10 Torr is 10 thousand microns. The boiling point of THC cannot really be practically reached in vacuum distillation this way that I know of. The breakdown of your other components would be too much.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F253749033063
You need to ditch those adapters of you want any chance of getting a high vac. Get a therometer well with the correct immersion length for your flask. If you have an internal probe on the heater that’s a better choice to use.
Check this out too it’s a Great read
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The only problem with the wells are getting smashed by a stir bar that decoupled, overshoot, and lack of total immersion. You can’t distill anymore once the puddle is smaller than the probe can reach. These are the reasons I control the mantle with a direct temp reading from the heating element. Imagine sitting on a phone book on a red hot stove. You don’t know it’s hot till the book is on fire! That’s what your probe experences.
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How do you know how long of a ta you need for your application? A few last pieces i still need to source before giving it a try.