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Author: Subject: Best Hotplate Stirrers
Abromination
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[*] posted on 3-2-2019 at 15:10
Best Hotplate Stirrers


The time has come, my Cuisimax low budget kitchen hotplate has died after 5 months of use (piece of shit died mid distilation) and I need a new hotplate with magnetic stirring.
Here comes the tricky part: I have a budget of 150 USD, it has to ship to Alaska and preferably it should come via Amazon.

Untill then, I'm going to patch the coil on my hotplate and finish my current project.
Anyone have any suggestions?




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Dr.Bob
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[*] posted on 3-2-2019 at 17:12


I have a couple of used Corning PC-351 stirring hotplates left that work OK. One has a fairly dirty top so I would sell it for $75, the other is nicer condition, so I would ask $85, plus $15 postage in the US, flat rate Priority mail, which is fine for AK. Both heat and stir, and they are both old but that model is nearly indestructible. I have been using some at work for almost a decade. I have some other Corning models I am working on checking, so I might have some other types, but I have ready now.
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Abromination
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[*] posted on 3-2-2019 at 17:30


Quote: Originally posted by Dr.Bob  
I have a couple of used Corning PC-351 stirring hotplates left that work OK. One has a fairly dirty top so I would sell it for $75, the other is nicer condition, so I would ask $85, plus $15 postage in the US, flat rate Priority mail, which is fine for AK. Both heat and stir, and they are both old but that model is nearly indestructible. I have been using some at work for almost a decade. I have some other Corning models I am working on checking, so I might have some other types, but I have ready now.

I know you as a reputable source and I would definitely buy from you, although unfortunately I can not buy or accept offers from the forum at the time due to some personal issues. I'm looking into the PC-351 however on ebay and if anyone knows any ebay reputable sellers for the model or similar I would be interested.




List of materials made by ScienceMadness.org users:
https://docs.google.com/spreadsheets/d/1nmJ8uq-h4IkXPxD5svnT...
--------------------------------
Elements Collected: H, Li, C, N, O, Mg, Al, Si, P, S, Fe, Ni, Cu, Zn, Ag, I, Au, Pb, Am
Last Acquired: Mg
Next: Bi
--------------
My blog: https://experimentalchemist.blogspot.com/
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Sulaiman
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[*] posted on 3-2-2019 at 23:44


Quote: Originally posted by Abromination  
Anyone have any suggestions?


Cheap hotplates fail in various ways but rarely due to the actual heating element,
so I'd check the heating element and if ok I would use one of the cheap eBay pwm controllers to repair and upgrade the hotpate,
(e.g. https://www.ebay.co.uk/itm/1x-Set-AC-110V-220V-SCR-Voltage-R...)
and spend the money on a heating mantle.
A little extra cash would allow the construction of an overhead stirrer that can be used in beakers on the hotplate or in RBFs in the mantle.
For example use
https://www.ebay.co.uk/itm/Simple-Value-170W-Hand-Blender-Wh...
https://www.ebay.co.uk/itm/1x-PTFE-Stirrer-Bearing-Adapter-f...
https://www.ebay.co.uk/itm/PTFE-Coated-Stainless-Steel-Stirr...
https://www.ebay.co.uk/itm/3D-Printer-Parts-Stepper-Motor-Fl...
plus a retort clamp on a stand.

[Edited on 4-2-2019 by Sulaiman]




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Heptylene
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[*] posted on 4-2-2019 at 02:17


There are loads of used hot plates on ebay. I'd go with a reputable brand like Corning. Then it depends what you need it for. Max temperature? External thermometer probe? Ceramic or metal top?

Also, if you don't have these already, invest in good magnetic stir bars. Don't skimp on these, they really make a world of difference and determine the scale of reactions you can conduct. I've used shitty stir bars for years and my reaction would fail because I couldn't stir thick reaction mixtures, precipitates, etc.
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Sulaiman
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[*] posted on 4-2-2019 at 04:41


Quote: Originally posted by Heptylene  
Also, if you don't have these already, invest in good magnetic stir bars. Don't skimp on these, they really make a world of difference and determine the scale of reactions you can conduct. I've used shitty stir bars for years and my reaction would fail because I couldn't stir thick reaction mixtures, precipitates, etc.

A good reason to use an overhead stirrer :P




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XeonTheMGPony
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[*] posted on 4-2-2019 at 05:14


I have a hot plate / stirrer, and a heating mantle with out, so I deff plan on getting an over head as well.
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[*] posted on 4-2-2019 at 13:01


Quote: Originally posted by Heptylene  
There are loads of used hot plates on ebay. I'd go with a reputable brand like Corning. Then it depends what you need it for. Max temperature? External thermometer probe? Ceramic or metal top?

Also, if you don't have these already, invest in good magnetic stir bars. Don't skimp on these, they really make a world of difference and determine the scale of reactions you can conduct. I've used shitty stir bars for years and my reaction would fail because I couldn't stir thick reaction mixtures, precipitates, etc.


Can you possibly point to a direction of these good stir bars? The ones I have are ebay sourced and the criterion has been the cost. They have worked fairly well for me so far but my future is looking at some mixtures which are more vicious.
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Abromination
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[*] posted on 4-2-2019 at 15:28


Quote: Originally posted by Sulaiman  

A good reason to use an overhead stirrer :P

Not in a distilation set up though.




List of materials made by ScienceMadness.org users:
https://docs.google.com/spreadsheets/d/1nmJ8uq-h4IkXPxD5svnT...
--------------------------------
Elements Collected: H, Li, C, N, O, Mg, Al, Si, P, S, Fe, Ni, Cu, Zn, Ag, I, Au, Pb, Am
Last Acquired: Mg
Next: Bi
--------------
My blog: https://experimentalchemist.blogspot.com/
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Sulaiman
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[*] posted on 4-2-2019 at 18:10


Quote: Originally posted by Abromination  
Quote: Originally posted by Sulaiman  

A good reason to use an overhead stirrer :P

Not in a distilation set up though.

A Claisen adapter (or multi-neck flask) allows overhead stirring during distillation.




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[*] posted on 4-2-2019 at 21:33


Quote: Originally posted by morganbw  

Can you possibly point to a direction of these good stir bars? The ones I have are ebay sourced and the criterion has been the cost. They have worked fairly well for me so far but my future is looking at some mixtures which are more vicious.


You might want to check out samarium cobalt stirbars. Also, just choosing the right size and shape for your mix (and stirrer, all mag stirrers aren't created equal, nor age equally) is a big part of it.

There will be many times when mechanical stirring is necessary, such as when working with iron. But any time I can use a mag stirbar I do.
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Abromination
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[*] posted on 4-2-2019 at 21:50


I know a lot of people will tell me to avoid this option, but as an Amazon hotplate is this a somewhat decent option?

https://www.amazon.com/gp/product/B01I1P1I9M?pf_rd_p=c294505...

I'm looking at a wide range of options and thought I should look at both sides.




List of materials made by ScienceMadness.org users:
https://docs.google.com/spreadsheets/d/1nmJ8uq-h4IkXPxD5svnT...
--------------------------------
Elements Collected: H, Li, C, N, O, Mg, Al, Si, P, S, Fe, Ni, Cu, Zn, Ag, I, Au, Pb, Am
Last Acquired: Mg
Next: Bi
--------------
My blog: https://experimentalchemist.blogspot.com/
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XeonTheMGPony
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[*] posted on 5-2-2019 at 03:35


Go for nothing under 600w heating power, and read thier specs care fully
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Heptylene
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[*] posted on 5-2-2019 at 14:07


Quote: Originally posted by morganbw  
Quote: Originally posted by Heptylene  
There are loads of used hot plates on ebay. I'd go with a reputable brand like Corning. Then it depends what you need it for. Max temperature? External thermometer probe? Ceramic or metal top?

Also, if you don't have these already, invest in good magnetic stir bars. Don't skimp on these, they really make a world of difference and determine the scale of reactions you can conduct. I've used shitty stir bars for years and my reaction would fail because I couldn't stir thick reaction mixtures, precipitates, etc.


Can you possibly point to a direction of these good stir bars? The ones I have are ebay sourced and the criterion has been the cost. They have worked fairly well for me so far but my future is looking at some mixtures which are more vicious.


I bought mine locally but I don't remember the brand. The oval ones are the most magnetic in my experience (because they have more volume to contain a magnet). I bought the largest oval ones that would fit in my flasks (small one for 250 ml, large one for 1 liter flask). Also those that have ridges in the middle (i.e. not simply cylindrical) are great for beakers because they spin well and don't jump around at high speeds.

[Edited on 5-2-2019 by Heptylene]
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Dr.Bob
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[*] posted on 5-2-2019 at 18:30


Quote: Originally posted by Abromination  
Quote: Originally posted by Dr.Bob  
I have a couple of used Corning PC-351 stirring hotplates left that work OK. One has a fairly dirty top so I would sell it for $75, the other is nicer condition, so I would ask $85, plus $15 postage in the US, flat rate Priority mail, which is fine for AK. Both heat and stir, and they are both old but that model is nearly indestructible. I have been using some at work for almost a decade. I have some other Corning models I am working on checking, so I might have some other types, but I have ready now.

I know you as a reputable source and I would definitely buy from you, although unfortunately I can not buy or accept offers from the forum at the time due to some personal issues. I'm looking into the PC-351 however on ebay and if anyone knows any ebay reputable sellers for the model or similar I would be interested.


I can list them on Ebay, but that adds about 15% to the price, due to their higher fees. If you buy via Paypal, and do it as a purchase, you get the same buyer protection as Ebay, but the fees are very low, and I pay them. But if you want to but one through Ebay, I can list one there, I already have a number of items there. I have a few types of stirbars there as well, plus others not listed, all good brands, not cheap Chinese ones that are not very magnetic. The Bel-art brand ones are the best, as they make them for almost every other US seller, such as Fisher, VWR, Aldrich, etc.
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[*] posted on 17-2-2019 at 17:09


Quote: Originally posted by Abromination  
I know a lot of people will tell me to avoid this option, but as an Amazon hotplate is this a somewhat decent option?

https://www.amazon.com/gp/product/B01I1P1I9M?pf_rd_p=c294505...

I'm looking at a wide range of options and thought I should look at both sides.


im going to order this one soon and see how it goes, looks pretty decent and has good reviews.
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Sulaiman
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[*] posted on 18-2-2019 at 02:32


180W is probably insuficcient to boil 2 litres of water,
even if it could boil 2l of water and all of the heating power (180W) goes to the water
(I guestimate maybe 80W of the 180W would got o lost heat)
to evaporate (or distill) 1 litre of water would take

(1000g x 2240J/g) / (180W) = 3.5 hours

so probably over 5 hours with some thermal insulation (e.g. Al foil) to boil off 1 litre of water.

If this is acceptable, or you only want to keep liquids warm with stirring,
then the hotplate-stirrer that you pointed to is ok.
For me it is too low powered.




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