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fusso
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[*] posted on 30-8-2018 at 17:28
Please recommend some decent hotplates


Please recommend some decent hotplates. Cheap/Chinese is ok as long as it is decent.
edit: please provide the brand and model.

[Edited on 31/08/18 by fusso]




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Tsjerk
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[*] posted on 30-8-2018 at 22:55


Get one with magnetic steering even if you don't need it now, you will be happy in the future.
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[*] posted on 31-8-2018 at 07:08


Quote: Originally posted by Tsjerk  
Get one with magnetic steering even if you don't need it now, you will be happy in the future.
Do you recommend the one you're using?



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[*] posted on 31-8-2018 at 07:37


I don't have one unfortunately
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fusso
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[*] posted on 31-8-2018 at 09:39


edit: please provide the brand and model.



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[*] posted on 31-8-2018 at 10:36


These Thermo Fisher ones are great, they are incredibly reliable, similar in quality to Corning hotplates, but it's a slightly less well known brand so they are cheaper to find.

https://www.ebay.com/itm/Thermo-Scientific-Thermolyne-Cimare...

https://www.ebay.com/itm/Thermolyne-SP46925-Cimarec-2-Magnet...

https://www.ebay.com/itm/Barnstead-Thermolyne-Cimarec-Hot-Pl...

Hotplate stirrers are not something you want to order from China. Trust me on this, I have had five break on me from all the top selling brands here, so think about what kind of performance you're going to get from that unbranded one off ebay.
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[*] posted on 31-8-2018 at 10:38


It depends partly on how much power you need.
The SH series of stirring hotplates, like the SH-2 and SH-3 are very low priced, but the SH-2 has only 180 Watts, so it is really only suitable for small scale work like with 14/20 or microscale equipment.

The SH-3 has something like 500 Watts, which is okay for most 19/22 or 24/40 work unless you need a lot of heat.

These SH models are sold on ebay by lots of different dealers, and some have different brand names on them, but search for SH-2 or SH-3 stirrer hotplate and you should find them.

I have an SH-2 which works fine, and there have been good reports on here by others of the SH-3.

But there's a lot to be said for looking around for a used model from a more major manufacturer.

You can find them for as little as the SH models sometimes, and they are often much more robust and powerful.

I've got an old Pyro-Magnestir that's just great, Very heavy duty with powerful magnets on a plate that's maybe 300mm on a side.

Got a little 500Watt Buchler that's nice too. It's got thermostatic control of the heating plate, and also very powerful stirring magnets in spite of its small diameter.

These are just examples that I bought, but Corning plates have a great reputation too, and can also be found cheap used once in a while.

However if I were in a rush to get a plate and didn't want to wait around for a deal, I think I'd buy an SH-3.




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ELRIC
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[*] posted on 31-8-2018 at 14:33


I would look into the Corning PC420 on eBay. You can find them for 150-250$ all the time
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[*] posted on 31-8-2018 at 15:11


I've been using an IKA C-Mag HS 7 digital for 4 years and I'm very satisfied with it.

Pros:
- 1000 Watts: It can heat up to 500 °C, w/ resolution of 1 °C. I've needed to heat things that high on several occasions.
- The heating surface is made of ceramic, so can withstand acids, bases, solvents, pirhana solution etc.
- You can plug in a thermometer probe and keep a bath at a fixed temperature within 1 °C. This is pretty useful for a water/oil bath for a distillation. But the best is that I can use this for melting point determination. Just put your capillary inside an oil bath and use the probe to heat to the desired temperature near the melting point.

Cons:
- Expensive: I bought it new for almost 700 $. It had 3 years warranty but still very expensive. Then again, I use every single time I'm in the lab, so a good investment I guess?
- Digital, so probably difficult to repair if it fails.

Last piece of advice: get good stir bars! Especially a very large oval one for the round bottom flasks. A large stir bar is necessary to get a good coupling with the rotating magnet. I used to have shitty stirbars, and investing in a few high quality ones changed my life.


3487000_1.jpg - 29kB
EDIT: added power rating.

[Edited on 31-8-2018 by Heptylene]
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[*] posted on 31-8-2018 at 17:56


I have a Corning PC-351. They are cheap and durable, and they work well with a wide variety of stir bars. The temperature control is really not that great but is usually fine. Also, they are only 560 watts IIRC, but that's respectable. I use heating mantles when I need precise temperature control.

I like the idea of getting a nice hotplate like the IKA C-Mag HS 7, but I had a hard time talking myself into buying even a used PC-351. A heating mantle, PID controller, and overhead stirrer together will run you far less than $700. The convenience of using a hotplate vs a heating mantle doesn't really justify the high cost of a high-end hotplate in my mind, but I don't have much experience with them, so perhaps I'm missing something. (Also, I'm just an amateur.)

I use a $10 Walmart hotplate quite a bit. They seem to have two heating modes: scorch at 1200 watts and off. They are usable with a heating bath. I've been tempted to break one down and wire it up with a PID controller....

Hotplates are much less efficient than heating mantles. Do not buy a hotplate that does not have a decent power rating. Any under 480 watts or so are not even worth considering.



[Edited on 2-9-2018 by JJay]




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[*] posted on 1-9-2018 at 07:39
Thermolyne


You and I spoke briefly regarding my Scilogex. When it works you'll love it... when it doesn't you'll wonder why no one at the company gives a hoot!

I use it when I need very accurate control of the temperature. It seems to excel at accuracy. But, if I want a hot plate that stirs, and can be on for days (many) at full temperature, then an old Thermolyne is the way to go. They are huge, inconvenient and heavy. Ugly too.

But, they can be maintained by any intelligent person and require almost no "propitiatory" parts to fix them. I don't like admitting that I've had a few disasters in the lab. Boil overs, and a small fire (out in a second, fire extinguisher made more mess than the fire, which didn't even leave a mark on hood). If it were the Scilogex that took that punishment I wouldn't even still have it. The Thermolyne, no problem... it took me two hours to completely disassemble it and clean the fire extinguisher crud and mineral oil from inside it. That was two years ago, and the thing hasn't missed a beat since.

The Thermolyne dosen't have a digital bone in it's body. No fancy readouts, no overheat circuits, it's a hot plate. It's crude, and tank like. Tough as nails and works each and every time. I have four plates/mantels and it is my favorite when I need a flat plate that will run indefinitely. It also gets nearly as hot as my hottest mantel. I can keep a sand bath at 350c. Not something that fancy Scilogex could come close to.

While on the same search you are on now, I noted Doug of Doug's Lab used one. I did a search and found two used. I paid fifty bucks for mine (and would gladly pay twice that). The other auction oddly enough was taken down due to an Ebay brain fart.

EDIT: I just checked ebay. I don't know if that does you any good where you are, but there is an 840 watt Thermolyne very similar to mine for $99.

This is the ebay listing

I don't have the money to spare at the moment, or I would have purchased it on the spot. As I continue to browse I note a number of them for sale. Some much cheaper that one I linked you to.

[Edited on 9-1-2018 by JScott]

[Edited on 9-1-2018 by JScott]

[Edited on 9-1-2018 by JScott]

[Edited on 9-1-2018 by JScott]
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[*] posted on 1-9-2018 at 09:38


It all depends on what you want a hotplate for;

if it will be your main heating source then I agree with most of the above


I think that money could be better spent on a heating mantle with stirring
and a cheap Chinese >=1kW hotplate for flat-bottom glassware, pots, pans etc..

. for distillations and refluxing a heating mantle with stirring is ideal

. anything worth heating and/or stirring for an extended period of time is worth putting in an rbf
- even if just to reduce dust etc.

. flat-bottomed glassware such as beakers can easily be stirred by hand as required

. with a sand/salt/oil/water bath a 1500W hotplate can be used to heat almost any size flask

The first three years of my chemistry I had a cheap hotplate and a small spirit burner.
I'd start with the cheapest hotplate that you can find
then later when you requuire a specific type of heating
you can invest in that.
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[*] posted on 1-9-2018 at 10:20


I bought a Corning PC351 in used but nearly perfect condition for about $120 on eBay. I like it because it's very simple. I thought about buying a fancy digital hot plate with a temperature probe, but if something breaks you're screwed -- I'm not aware of a single manufacturer that will sell a non-commercial entity the replacement parts.

I'm in the process of building a PID controller and separating the circuits of my hot plate (separate 120V inputs for the magnetic stirring and the heating element), so I'll have digital temperature control.
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[*] posted on 1-9-2018 at 17:22


I'm selling a hot plate, see here: https://www.sciencemadness.org/whisper/viewthread.php?tid=84...



As below, so above.

My blog: https://denovo.substack.com
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[*] posted on 2-9-2018 at 11:04


Quote: Originally posted by SWIM  
It depends partly on how much power you need.
The SH series of stirring hotplates, like the SH-2 and SH-3 are very low priced, but the SH-2 has only 180 Watts, so it is really only suitable for small scale work like with 14/20 or microscale equipment.

The SH-3 has something like 500 Watts, which is okay for most 19/22 or 24/40 work unless you need a lot of heat.
Is temperature output dependent on watt?



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[*] posted on 2-9-2018 at 11:15


Quote: Originally posted by fusso  
Quote: Originally posted by SWIM  
It depends partly on how much power you need.
The SH series of stirring hotplates, like the SH-2 and SH-3 are very low priced, but the SH-2 has only 180 Watts, so it is really only suitable for small scale work like with 14/20 or microscale equipment.

The SH-3 has something like 500 Watts, which is okay for most 19/22 or 24/40 work unless you need a lot of heat.
Is temperature output dependent on watt?

Time to heat a substance will depend on how many watts you can dump into it. Here's a calculator for water. Actual results will be longer because of imperfect heat transfer, etc. https://bloglocation.com/art/water-heating-calculator-for-ti...
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[*] posted on 8-9-2018 at 12:18


I have seen may hotplates stirrers out there as I used to do repairs on them. I have played around with every brand. You can't judge off brand because some good brands have really shitty models. I listed the best hotplate models which gave the least problems:

Aluminum/SS top:
-Heidolph MRHei (all models of Heidolph are stellar). Last the longest never break.
-IKA RCT Basic (older models with manual control knobs). Don't get the new models. Their elements burn all the time.

Ceramic top:
-Cimarec SP131325, Isotemp 11-100-49SH, StableTemp 03407-100. All produced from the same factory in Malaysia. They are pretty good quality and last pretty long.
-VWR VMS and IKA C-MAG are made by the same factory. They are both pretty good. Their elements are good quality.
-Corning PC-320 and 520 last longer than the 620, 420. Corning PC-420, 620 are okay, but do not get the digital version. They outsourced assembly and production to Mexico and to be honest they blow fuses for no reason and have really shitty transistors that blow all the time.
Corning PC-351 are good too but it's hard to find a good condition one (they haven't been produced in YEARS)

Let me know if you have other questions.
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[*] posted on 8-9-2018 at 14:02


Quote: Originally posted by Keftedes89  
I have seen may hotplates stirrers out there as I used to do repairs on them. I have played around with every brand. You can't judge off brand because some good brands have really shitty models. I listed the best hotplate models which gave the least problems:

Aluminum/SS top:
-Heidolph MRHei (all models of Heidolph are stellar). Last the longest never break.
-IKA RCT Basic (older models with manual control knobs). Don't get the new models. Their elements burn all the time.

Ceramic top:
-Cimarec SP131325, Isotemp 11-100-49SH, StableTemp 03407-100. All produced from the same factory in Malaysia. They are pretty good quality and last pretty long.
-VWR VMS and IKA C-MAG are made by the same factory. They are both pretty good. Their elements are good quality.
-Corning PC-320 and 520 last longer than the 620, 420. Corning PC-420, 620 are okay, but do not get the digital version. They outsourced assembly and production to Mexico and to be honest they blow fuses for no reason and have really shitty transistors that blow all the time.
Corning PC-351 are good too but it's hard to find a good condition one (they haven't been produced in YEARS)

Let me know if you have other questions.


Any opinion on the Scilogex MS-H-Pro (or the rebranded Chemglass version), or the Chemglass Optichem? Also, how did you order parts for repairing hot plates? All of the big brands seem to make you RMA a defective unit and therefore require a warranty.
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[*] posted on 8-9-2018 at 17:09


Quote: Originally posted by Keftedes89  
I have seen may hotplates stirrers out there as I used to do repairs on them. I have played around with every brand. You can't judge off brand because some good brands have really shitty models.
Let me know if you have other questions.


Thanks for the list, that is similar to my experience, but I don't know some of those. It's great to have someone with good information.

BTW, if you are interested in fixing a few more, I have several that need some work, but I don't know anyone who will fix them nearby. I can do simple things like just swap a cord, but not diagnose the fancier ones.

Bob
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[*] posted on 8-9-2018 at 17:11


Quote: Originally posted by monolithic  
Quote: Originally posted by Keftedes89  
I have seen may hotplates stirrers out there as I used to do repairs on them. I have played around with every brand. You can't judge off brand because some good brands have really shitty models. I listed the best hotplate models which gave the least problems:

Aluminum/SS top:
-Heidolph MRHei (all models of Heidolph are stellar). Last the longest never break.
-IKA RCT Basic (older models with manual control knobs). Don't get the new models. Their elements burn all the time.

Ceramic top:
-Cimarec SP131325, Isotemp 11-100-49SH, StableTemp 03407-100. All produced from the same factory in Malaysia. They are pretty good quality and last pretty long.
-VWR VMS and IKA C-MAG are made by the same factory. They are both pretty good. Their elements are good quality.
-Corning PC-320 and 520 last longer than the 620, 420. Corning PC-420, 620 are okay, but do not get the digital version. They outsourced assembly and production to Mexico and to be honest they blow fuses for no reason and have really shitty transistors that blow all the time.
Corning PC-351 are good too but it's hard to find a good condition one (they haven't been produced in YEARS)

Let me know if you have other questions.


Any opinion on the Scilogex MS-H-Pro (or the rebranded Chemglass version), or the Chemglass Optichem? Also, how did you order parts for repairing hot plates? All of the big brands seem to make you RMA a defective unit and therefore require a warranty.


I had many Chemglass (Red Version), which is the Scilogex rebranded like you said, come in for repair. Most common problems were the elements burned and the thermoresistor temperature sensors were shorted. Motors caught rust but stayed functioning (was always surprised about this). The other problem I always saw was the leads rusted. There's a power supply board that had rusted leads all the time. Its definitely of lower quality than the ones I listed (they use cheaper components for their build), but for it's price it's pretty decent as long as you don't use it everyday.

The best chemglass rebrand was the Optimags originally the IKA RET/RCT digital which only had one flaw (switch DPST failed easily). The chemglass Arex are pretty good too I think those are the VELP rebranded.

Most of the parts I used were suitable replacements. If you try to get them from the manufacturer they will try to sell you full pcb's, full top plate assemblies that are overpriced. You can find scilogex elements on alibaba but the thermoresistors are really hard to find so you better pray they don't fail. Worse scenario you use a donor unit.
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[*] posted on 8-9-2018 at 17:30


Quote: Originally posted by Dr.Bob  


BTW, if you are interested in fixing a few more, I have several that need some work, but I don't know anyone who will fix them nearby. I can do simple things like just swap a cord, but not diagnose the fancier ones.

Bob


Send me a pm with the models and their problem. Maybe you can ship them to me and we can work something out.
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[*] posted on 8-9-2018 at 17:42


Quote: Originally posted by Keftedes89  
Quote: Originally posted by monolithic  
Quote: Originally posted by Keftedes89  
I have seen may hotplates stirrers out there as I used to do repairs on them. I have played around with every brand. You can't judge off brand because some good brands have really shitty models. I listed the best hotplate models which gave the least problems:

Aluminum/SS top:
-Heidolph MRHei (all models of Heidolph are stellar). Last the longest never break.
-IKA RCT Basic (older models with manual control knobs). Don't get the new models. Their elements burn all the time.

Ceramic top:
-Cimarec SP131325, Isotemp 11-100-49SH, StableTemp 03407-100. All produced from the same factory in Malaysia. They are pretty good quality and last pretty long.
-VWR VMS and IKA C-MAG are made by the same factory. They are both pretty good. Their elements are good quality.
-Corning PC-320 and 520 last longer than the 620, 420. Corning PC-420, 620 are okay, but do not get the digital version. They outsourced assembly and production to Mexico and to be honest they blow fuses for no reason and have really shitty transistors that blow all the time.
Corning PC-351 are good too but it's hard to find a good condition one (they haven't been produced in YEARS)

Let me know if you have other questions.


Any opinion on the Scilogex MS-H-Pro (or the rebranded Chemglass version), or the Chemglass Optichem? Also, how did you order parts for repairing hot plates? All of the big brands seem to make you RMA a defective unit and therefore require a warranty.


I had many Chemglass (Red Version), which is the Scilogex rebranded like you said, come in for repair. Most common problems were the elements burned and the thermoresistor temperature sensors were shorted. Motors caught rust but stayed functioning (was always surprised about this). The other problem I always saw was the leads rusted. There's a power supply board that had rusted leads all the time. Its definitely of lower quality than the ones I listed (they use cheaper components for their build), but for it's price it's pretty decent as long as you don't use it everyday.

The best chemglass rebrand was the Optimags originally the IKA RET/RCT digital which only had one flaw (switch DPST failed easily). The chemglass Arex are pretty good too I think those are the VELP rebranded.

Most of the parts I used were suitable replacements. If you try to get them from the manufacturer they will try to sell you full pcb's, full top plate assemblies that are overpriced. You can find scilogex elements on alibaba but the thermoresistors are really hard to find so you better pray they don't fail. Worse scenario you use a donor unit.


W/r/t the IKA rebrand, are you talking about the red Optimag e.g. https://www.ebay.com/itm/Chemglass-Life-Sciences-OptiMag-ST-... or did you mean the green Optichem e.g. https://www.ebay.com/itm/Chemglass-Optichem-Digital-Hotplate...

I assume the probe is a standard PT100/PT1000 probe with what looks like a DIN connector? Have you had any luck buying a cheap Chinese PT100 probe off eBay rather than spending the outrageous $200+ the manufacturers charge?

[Edited on 9-9-2018 by monolithic]
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[*] posted on 8-9-2018 at 19:25


Quote: Originally posted by monolithic  

W/r/t the IKA rebrand, are you talking about the red Optimag e.g. https://www.ebay.com/itm/Chemglass-Life-Sciences-OptiMag-ST-... or did you mean the green Optichem e.g. https://www.ebay.com/itm/Chemglass-Optichem-Digital-Hotplate...

I assume the probe is a standard PT100/PT1000 probe with what looks like a DIN connector? Have you had any luck buying a cheap Chinese PT100 probe off eBay rather than spending the outrageous $200+ the manufacturers charge?

[Edited on 9-9-2018 by monolithic]


Yea that's the one. I got those backwards. The optimag is the scilogex rebrand. The optichem is the IKA rebrand. You can connect a PT100 probe but you have to find the DIN sockets that recognize the resistance. I haven't personally constructed my own. You have to find which slots it reads the resistance from (you can test this before you buy with spare resistors). I know you need 4 slots of the DIN for the PT1000 since it's twin PT1000. It might be easier to find one that comes with the probe. The set usually goes for 200-300 bucks on ebay.
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[*] posted on 9-9-2018 at 16:40


Just found a box with a couple of working PC-320 Corning stirring hotplates while looking for some other stuff tonight. They are basic stirring hotplates that work well for most lab uses. I have been selling them for $100 each plus about $15-20 for shipping, depending on where you are located.
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