Sciencemadness Discussion Board

Help Getting a New Magnetic Stirrer

BlackDragon2712 - 28-10-2017 at 00:44

So… My old stirrer passed away and I’m looking to bring a new one into home but I really have no idea about how to judge between one stirrer and another… I’ve been looking in eBay and wanted your opinion guys, which one of these is a better option? I am looking for something that can stir at any rate and that hopefully will be able to heat to at least 200°C without burning itself down :(

Or if you have something else in mind… what is my best option with a budget of roughly 80 dollars?

> https://www.ebay.com/itm/220V-Magnetic-Stirrer-Mixer-SH-2-St...

> https://www.ebay.com/itm/1000ML-Laboratory-Lab-Magnetic-Stir...

> https://www.ebay.com/itm/85-2A-Magnetic-Stirrer-Mixer-with-H...

> https://www.ebay.com/itm/Top-Grad-HJ-3-Digital-Control-Const...

Thanks for the help guys!

JJay - 28-10-2017 at 01:19

Those stirrers have insufficient wattage to boil water. I am a big fan of the Corning PC-351 (https://www.ebay.com/p/Corning-Pc-351-6x7-Hot-Plate-Stirrer-...). I have used them in college chemistry classes, and my first stirrer was a PC-351. The one I currently own is probably my most-used lab appliance. They are pretty popular, and Corning makes several similar models such as the PC-320. If you shop around, you can probably find a used PC-351 or similar for under $100.

The temperature control is a little primitive, but at 615 watts, the PC-351 far more versatile than the stirrers above. It can boil several liters of water. It can reach a low red heat. It is robust and non-sparking, and the top is impervious to harsh chemicals like boiling sulfuric acid.

BlackDragon2712 - 28-10-2017 at 01:54

Thanks! I know that plate, the problem is that it is way out of my current budget, 200$ just for the plate +100$ for shipping, hell that's expensive!...
I know I probably won’t get something great with barely 80 bucks but I just want the best I can possibly get with that many, something just decent enough.

JJay - 28-10-2017 at 02:04

I do not in any way recommend low-wattage hotplate/stirrers, but if absolutely necessary, you can use a non-heating or low-heating stirrer with oil bath and an immersion heater (like this one: https://www.ebay.com/itm/110V-1000W-Water-Heater-Portable-El...) and reach around 200 C or so. You'll want to hook up a dimmer switch or variac to the immersion heater if you do.

Edit: That heater is probably overkill, actually... you might like this one better: https://www.ebay.com/p/500w-Electric-Water-Heater-Liquids-Im...


[Edited on 28-10-2017 by JJay]

Deathunter88 - 28-10-2017 at 17:29

Yep, unfortunately you just can't get a functional magnetic stirrer hotplate for 80 bucks. Any that are in that price range are not powerful to even boil half a liter of water.

SWIM - 28-10-2017 at 19:33

I see new 500 watt SH-3 hotplate stirrers for $94 or best offer on Ebay right now. (free shipping)
If it's listed as best offer they're probably willing to knock $10 or $15 off.

This looks like a bigger more powerful product by the guys who make the SH-2, but I don't know anything else about it.

If it were me trying to get a budget heater/stirrer I'd use JJay's idea and maybe try putting together a home-made stirrer for it to really keep the costs low.

Oil baths do mean more clean-up, but It's not that big a deal. Another nice thing about that kind of rig is you can upgrade it later with a heat sensor to control the bath temp pretty easily.



JJay - 28-10-2017 at 20:13

I have used immersion heaters with oil baths lots of times, and they work OK. (I got the idea out of a book I picked up from a box of free books outside a chem prof's office.) I definitely prefer heating mantles or just heating on a hotplate, but for very precise heating, it is hard to beat an oil or water bath.

Dr.Bob - 29-10-2017 at 14:17

I think I still have some working used Corning hotplates in storage, I have been selling them for $100 plus about $15 for shipping, depending on condition. If you are still interested, I can try to find which models I have left, but mostly the ones JJay described.

ninhydric1 - 29-10-2017 at 14:37

I, in fact, do have an SH-3 hotplate stirrer and for only 94$ it's surprisingly sturdy. It reaches 100 C in about 10 minutes and is able to distill water with ease. I've had it since June and have used it countless times to boil off water or to make solutions. For the price, it seems well worth it.

arkoma - 29-10-2017 at 18:09

I found a NICE PC-351 on eBay for $80. Just gotta persevere.

organicchemist25 - 29-10-2017 at 18:26

I have 2 of these and really really like them. they go up to 550 degrees C, have a stirrer and a temperature probe. Also, it has a bar you can put in the back to hold stuff up with a utility clamp if needed. Built nice and to last. I know its pricey, but you will have a nice one.

https://www.ebay.com/itm/Corning-PC-420D-Digital-Hot-Plate-S...