Magnetic Stirrer Hot Plate - 716°F Temperature, 2000 RPM, 5x5 inch, 180W Heating Power - Magnetic Stir Plate Mixer with Digital Control for Scientific Research, Homebrewing, and More

I really like the Anzeser hotplate stirrer. After reading the reviews, I found a work around for a couple problems people often mentioned. I plugged it into a “Kill A Watt” P4400 meter that I’ve had for years, and set it to measure watts. This allowed me to quantify the amount of power the hotplate was getting. Using an inexpensive thermocouple thermometer, I measured the hotplate surface temperature at 10 watt intervals from 10 watts to 180. This allowed me to easily replicate hotplate temperatures, and avoid overheating the little Anzeser. Also, some of the reviews complained about the magnetic stirrer losing its grip on the stir bar. I found the stirrer worked quite well, as long as the volume of liquid is one liter or less, not a higher viscosity than water, and contained in a lab beaker, which typically has a fairly thin bottom. Anything with a thicker bottom will diminish the magnetic attraction, possibly causing spinouts. There’s something else you should know about magnets. The strongest type is neodymium, but it turns out they are not very heat tolerant, unless Dysprosium (Dy) or terbium (Tb) is added during the manufacturing process. If you heat a magnet past its working temperature limit, it starts to permanently lose some of its magnetic strength. I contacted Sakerz, the seller, to find out more about the stirrer magnets. They responded very quickly, telling me that the stirrer drive magnets are neodymium, treated with Dysprosium (Dy) or terbium (Tb), with a maximum working temperature of 180 C, which is pretty impressive at this price point. My advice would be to not heat the hotplate past the max temperature of 520 degrees F (271 C) or for more than 4 hours at high heat, as mentioned on the web site, to prevent heat damage to the stirrer drive magnets. Just out of curiosity, I set up a test platform with a computer cooling fan I pulled out of an old computer, to blow air into the cooling slots on the bottom of the hotplate, and a thermocouple thermometer inserted next to the drive magnets. The fan I used is a two wire 12 volt brushless DC fan, 80 mm square, rated at 32 cfm, powered by a plug in AC adapter I had in my electronics parts box. After 30 minutes at a plate temperature of 271 C, the magnet temperature was only 34 C, and it seemed to stabilize at that temperature. The airflow through the case also served to cool the stirrer motor and control circuits. I haven’t tried a run of several hours yet, but I’m confident that with the fan running, the magnets would stay at a safe temperature for even longer than that. I can’t comment on the long term durability since I’ve only had it a short time, but if I don’t push it past its limits, I think it will hold up well. So I would call it a good value at $45, and Sakerz, the seller, also provided good customer service, by answering my questions quickly.

I'm a retired chemistry teacher. While this is not the heavy duty hot plate stirrers we use in class it is MORE THAN SUFFICIENT for home use. I put it on a smart plug and can set a timer. I appreciate that it included a spare fuse, cause, someday... I taped it to the case.

Exactly as advertised, arrived on time.

The heating on this stirrer is actively dangerous. The marketing claims it's up to 180W but the reality is that the first tiny fraction of the meter is 120W and the vast majority of it is 230W, as measured with a Kill-a-Watt. Even though I had this on what I thought was an extremely low setting, it still managed to shatter a dish that had claimed to be borosilicate (though in retrospect, I think that it wasn't and that another Amazon seller had lied to me--it shattered at around 130°C afaict). Perhaps this turns on and off the heating with a duty cycle like cooking pates, but the fact of the matter is that it's too coarse to be useful for anything other than all the way on.

Received and tested. All works as described. Heat pad did not make it to 500 degrees but did go 488 which is no big deal to me. With a non-viscous liquid such as water the spinner does not go slow enough to prevent cavitation. I can turn it down all the way and a fraction more it cuts off. But at the lowest point prior to cut off it spins fast enough to pull in an occasional micro bubble. I don't think this would happen once I added a foreign material but would be nice if it had a little mor control at low speed.