Best Magnetic Stirrers

[shortly]

Santa was thinking of bringing a heated magnetic stirrer for xmas.

However he's become more than a little lost in the maze of stirrers. Can anyone recommend a good reliable model or brand suitable for up to 2L with a temp range from the 30's up to 110c'ish, its mostly for yeast work & possibly a bit of agar.

Any advice or guidance would be greatly appreciated. 

[Torsten]

This is the only one I use. I have about 6 or 7 of them, with the oldest one over 10 years old and still going strong. The only niggle is that once they get older, if they don't get used for a few months the spinner seizes up a bit. Easily dislodged with a screwdriver and then just blow some WD40 onto it to keep it going for a couple of years before it needs it again. Temp is very stable, spinner is strong enough to drag big eggs and giant bars. hotplate seems to last forever (all other brands I've tried rarely make it past one year).
We also sell them because they are so awesome.
http://www.webstore.kodaphytorium.com.au/magnetic_stirrer_hotplate_device_pr_2350.php

[shortly]

Thanks Torsten

Sounds like just the ticket.

What is the Min temp setting on it? And what increments does it go up in?

[ballzac]

Are the cheap, Chinese ones on Ebay completely useless, or are they okay if you're on a tight budget and not expecting it to last forever? More importantly, are there any safety concerns if you're using them for distilling organic solvents?

[Alice]

OK I have a bit of experience with this, I've used probably hundreds and currently have over 25 hotplates in my labs ranging from cheapo chinese brand to $6K programmable ramping 550 deg etc. The majority I've ordered personally and all have been tested in our labs against very decent thermocouples.

 

In my experience the cheapo Chinese ones are really shit for a proper lab because they are generally not accurate (at all, like 40 degrees out in some cases), the stirrers get noisy and usually wobble, heat distribution across the plate is terrible, wiring is often shit so you end up resoldering connections and in general it really shits me to tears even looking at them. We now use mainly on particular brand digital hotplate stirrer and you pick them up for between $700 and $2K (usually about $1200 I guess, always on sale somewhere) depending on quantity you buy and promotions they're running at the time. They rock.

 

However, unless you are using them day in day out then just get the cheap ones, use a thermometer to measure the real temperature and save your hard earned pennies for some decent glassware instead. If it's just for tinkering around then it will be fine.

[shortly]

I would rather spend the extra $'s and get a unit that will last, probably not as long as i would like. But a few years at least.

I've got enough ElCheapo stirrers as it is, computer fans with HDD magnets glued onto them, They work, but to maintain a fairly constant temp i have to keep them in a foam box with a heater cable. Which does not give fine control over the temp. Noisy & i have to have the tops poking out so that they can breathe, but it kinda works. 

I'm expecting the new one to run for 2-4 days a week at this stage. Depending upon how things pan out?

[Alice]

I would rather spend the extra $'s and get a unit that will last

 

If you want something that will last then that one Torsten linked to is pretty solid, you wouldn't get as reliable a digi for that price. That design hasn't changed in 20 years but it works, we've still got a few of those about and they just keep going. The temp dials are surprisingly well calibrated but you'll still need a thermometer though if you want to know the exact temp, however most people don't really need super fine accuracy for just boiling or dissolution of reagents. The modern digis with external probe are more convenient in that regard.

 

If I were in the market for home use I'd be looking for a decent second hand unit that's already proven itself in someones lab for a decade.

[Darklight]

Yep, as Torsten and Alice said, those IEC units are the best for general use.
 

Have had one for 10 years, no probs. Totally worth the outlay

[Torsten]

Lowest temp I got from that unit was just enough to keep my chicks warm ;)   That first number is 50C and the dial is just below that.

 

Temp dial is quite reliable as long as you approach from the same direction. ie don't expect reaching the 150C mark from clockwise to give you the same temp as when from anticlockwise. For low temp work there will also be a difference with ambient temps, but you will get that for anything that isn't probe controlled. I use a few of the cheap chinese probe controlled ones too, but I don't think any of them have lasted me a year of weekly use. And don't think that the ones sold locally by lab suppliers are any better just because they are sold locally. Many of them are the same cheap chinese ones, just with a different label and a very different price tag.