Sciencemadness Discussion Board - Recommendations for a hotplate?

Recommendations for a hotplate?

Tungsten.Chromium - 26-10-2014 at 11:22

I'm really starting to get into my hobby of chemistry and while studyino it has taught me some cool stuff. I want to try a few things.

I have a few various Pyrex flasks and such, but it looks like a key thing I'm missing is a hot plate/magnetic stirrer. I've been researching around it looks like this is one of the things you want to spend a few bucks on so it lasts(sort of like an electrician's multimeter).

The one I've been looking at is this one: http://www.amazon.com/gp/aw/d/B004DGIC0W?pc_redir=1414184305...

It looks like corning makes the best stuff, and this is one of the best models they have, but the cheapest I've been able to find it anywhere is over 500.00. Is it worth the money to invest in this one or am I better going with a cheaper option. I really like how it has digital readouts of the stir RPM and temperature

Texium - 26-10-2014 at 11:40

You might want to check out ebay. I found this one there:

It's old, but it works great. I got it for only $45 including shipping!

j_sum1 - 26-10-2014 at 14:49

Really consider what you actually need. there will be plenty to spend your money on.
My magnetic stirrer is an old PC fan with two button neodymium magnets stuck onto it with a hot glue gun. Stirrer bars were $7 from China on eBay. I am using a camp stove as a burner. I might bum around some yard sales to see if I can pick up a hot plate of some variety (Ok, the cheap motel variety).
I am obviously going to run into trouble the day I wish to stir and heat at the same time. Then my setup will be a PITA. However, when that day comes I will shell out for one of these or something similar: http://www.ebay.com.au/itm/271274303830?ssPageName=STRK:MEWA...

And as a bonus I will have some stirring and heating gear to allow me to do two things at once.

aga - 26-10-2014 at 14:59

Choice of Hotplate/Stirrer basically comes down to two factors:-

1. Vanity
2. Money

The really expensive ones look nice, heat stuff and stir stuff.

The cheap ones look less nice, heat stuff and stir stuff.

The second hand ones look awful (if they ever really got used), heat stuff, and stir stuff.

Home made stuff can look, er, interesting, yet can still heat stuff, and stir stuff.

j_sum1 - 26-10-2014 at 15:00

Ok. I'm interesting.

forgotpassword - 26-10-2014 at 15:14

Quote: Originally posted by aga

Choice of Hotplate/Stirrer basically comes down to two factors:-

1. Vanity
2. Money

The really expensive ones look nice, heat stuff and stir stuff.

The cheap ones look less nice, heat stuff and stir stuff.

The second hand ones look awful (if they ever really got used), heat stuff, and stir stuff.

Home made stuff can look, er, interesting, yet can still heat stuff, and stir stuff.

Well said.

DrMario - 26-10-2014 at 15:41

Quote: Originally posted by Tungsten.Chromium

I'm really starting to get into my hobby of chemistry and while studyino it has taught me some cool stuff. I want to try a few things.

I have a few various Pyrex flasks and such, but it looks like a key thing I'm missing is a hot plate/magnetic stirrer. I've been researching around it looks like this is one of the things you want to spend a few bucks on so it lasts(sort of like an electrician's multimeter).

The one I've been looking at is this one: http://www.amazon.com/gp/aw/d/B004DGIC0W?pc_redir=1414184305...

It looks like corning makes the best stuff, and this is one of the best models they have, but the cheapest I've been able to find it anywhere is over 500.00. Is it worth the money to invest in this one or am I better going with a cheaper option. I really like how it has digital readouts of the stir RPM and temperature

That is, indeed, one of the best hotplates under US$1000. It's the kind my research institute would buy, because
- it uses PWD to adjust the hotplate temperature, which allows it to quickly reach the desired temperature, with little overshoot (cheaper hotplates use a simple on/off system). This is combined with a CPU-controlled algorithm, again, to attain the target temperature quickly and with low overshoot.
- it allows for accurate temperature adjustment with very low bias.
- very durable ceramic plate surface. You start to appreciate this when your hotplate is as heavily used as ours.
- option to add external temperature sensor (or, as Corning calls them, "external controller").
- uniform temperature distribution across the plate. You will appreciate this... quite rarely, I guess, if all you need to do is heat a beaker. If you need to process wafers or other flat samples (with films), you will want this feature - but to be honest, you'd need a larger hotplate.

How important are the features listed above? For an amateur, probably not too much. I am an amateur too (in addition to my day job), and I know I wouldn't invest in such a hotplate. Not unless I become unexpectedly rich, which isn't going to happen as I don't play the lottery.

Finally, that Corning hotplate will only fully shine if you also buy this:
http://www.amazon.com/Corning-External-Temperature-Controlle...
- that is, the external thermal sensor that allows you to adjust the temperature of the liquid you're heating, rather than just adjust the temperature of the plate on which you are heating. These Corning thermal sensors are quite expensive, and adding it all together, you'll have to pay US$ 900.

Too much, IMHO, for an amateur.

Instead, look for the cheaper Chinese hotplates that go for about US$100 including shipping. Everything on those models is worse than with the Corning hotplate, but you still can stir and heat, and have a reasonable control over the temperature.

[Edited on 26-10-2014 by DrMario]

DrMario - 26-10-2014 at 15:46

Quote: Originally posted by aga

Choice of Hotplate/Stirrer basically comes down to two factors:-

1. Vanity
2. Money

Not at all true. The expensive hotplates definitely have their place. Not in an amateur lab perhaps, but their raison d'etre has nothing to do with "vanity".

jamit - 26-10-2014 at 16:13

The hotplate above is not good. It may be cheap but it's too old and unreliable and cosmetically very ugly - haha. The best hotplate/stirrer combo is manufactured by Corning. Any one of the following model will be an excellent addition to any home lab: PC-351, PC-320 or PC-420. I personally prefer the PC-420 model. They will cost about 150.00 on ebay, used. I used my hotplate stirrer quite a bit so I rather make some investment. Good luck.

NOV:5 - 26-10-2014 at 16:20

I guess I'm near about the same place. It's probably a newbie thing, scouring Ebay looking for gear. I've had quite an education on glassware..still wondering how one decides on a joint size standard...

I did the the same thing you've done when it came to a hot plate/stirrer... Initially I bought a $20 hot plate at Walmart. It worked but I wanted some indication of temperature..
I looked all over ebay, tons of choices from top to bottom. Ended up buying the 10 x 10 Corning digital with probe at Amazon...

Mainly because I wanted digital, the corning looked like a solid unit, and it is.
Looking for a centrifuge now, will probably get that used..

Edited to add;
So far the most startling thing cost wise, has been books..

[Edited on 27-10-2014 by NOV:5]

[Edited on 27-10-2014 by NOV:5]

Texium - 26-10-2014 at 16:50

Quote: Originally posted by jamit

The hotplate above is not good. It may be cheap but it's too old and unreliable and cosmetically very ugly - haha. The best hotplate/stirrer combo is manufactured by Corning. Any one of the following model will be an excellent addition to any home lab: PC-351, PC-320 or PC-420. I personally prefer the PC-420 model. They will cost about 150.00 on ebay, used. I used my hotplate stirrer quite a bit so I rather make some investment. Good luck.

If you're referring to the hotplate that I have, I've tested it, and it works great. It's got a durable ceramic plate and the whole thing is built like a ton of bricks. My theory is that if it's continued working well for the past 40 years it's not going to give out any time soon!

Dr.Bob - 26-10-2014 at 17:16

I have a few more older used Corning stirring hotplates that I am currently checking, cleaning, and testing. I have sold most of these used ones for $100 plus shipping, which is about $20. A few need new cords, which is what I am working on now. It turns out that DCM, DMSO, DMF, and many other solvents are rough on the cords and soften the plastic a lot. :-( But I have lots of replacement cords from other items.

I have a few used ones, mostly 351 type or other older ones. Most are a little stained or dirty, but I have been using the same models for years in the lab at work, some of those are 20+ years old, and still work well. If people are interested, let me know and I can make a waiting list. Once I get some ready, I will go by the people who were first to ask. I also have one or two stirring only plates, maybe also one hot plate only (no stirring). The stir plates are great for use with heating mantles and are a little cheaper

j_sum1 - 26-10-2014 at 17:26

Thanks Dr Bob. I think I know the answer to this, but how much would it cost to ship to Australia?
If the total cost could be kept below $150 I might be interested in one of these.

DrMario - 26-10-2014 at 18:10

Dr.Bob, in which country are you and your Corning hotplates? USA? In that case j_sum1 may not be able to use them. And neither could I

DrMario - 26-10-2014 at 18:13

Quote: Originally posted by zts16

You might want to check out ebay. I found this one there:

It's old, but it works great. I got it for only $45 including shipping!

My greatest issue with that hotplate is that I have no knowledge of the plate's temperature, and no way to adjust said temperature.

Texium - 26-10-2014 at 19:04

Quote: Originally posted by DrMario

Quote: Originally posted by zts16

You might want to check out ebay. I found this one there:

It's old, but it works great. I got it for only $45 including shipping!

My greatest issue with that hotplate is that I have no knowledge of the plate's temperature, and no way to adjust said temperature.

Yes, unfortunately the plastic dial that shows what temperature it's at is missing.

DrMario - 26-10-2014 at 22:35

Quote: Originally posted by zts16

Quote: Originally posted by DrMario

Quote: Originally posted by zts16

You might want to check out ebay. I found this one there:

It's old, but it works great. I got it for only $45 including shipping!

My greatest issue with that hotplate is that I have no knowledge of the plate's temperature, and no way to adjust said temperature.

Yes, unfortunately the plastic dial that shows what temperature it's at is missing.

And even if it were there it would be too imprecise to indicate anything meaningful.

Really, that's my only (but pretty fundamental) gripe with your hotplate. Otherwise, it's quite solid.

j_sum1 - 26-10-2014 at 22:54

Like I said before, consider what you actually need.
If you actually need precise control over the exact temperature you are providing then you will need something flash. Me, the most I am likely to need to do is put a thermometer in my flask to find out what is going on. Too hot and I turn it down. Too cold and I turn it up. i suspect this is typical of most hobby chemists.
To answer the original question, you don't need the fancy schmancy hotplate. Spend your money on something else until you do need it. By then you will have the experience and knowledge to know exactly what your requirements are. (Buying something more than what you need could amount to vanity. Or a misplaced sense of convenience. Or having too much money. Or something else. But whatever it is, for a beginner it is not chemistry related.)

diddi - 27-10-2014 at 00:08

temp stability is important if you are refluxing or distilling. and variable stirrer speed I found very important as well.

Dr.Arz - 27-10-2014 at 01:46

Is the hotplate strong enough? I have found that weaker, less than 500 watt plates are pretty toyish on doing anything unless you do 50ml volumes and have 8 hours time to distill them. Plus if you gonna do vacuum distillations you will need magnetic stirring or it will puke all up.

Just for you to know the chinese bante plate is horrible. It takes half an hour to heat 50ml of water to boil and the stirrer is so unbalanced it will vibrate the contents off the plate in no time.

[Edited on 27-10-2014 by Dr.Arz]

j_sum1 - 27-10-2014 at 02:21

Quote: Originally posted by Dr.Arz

Just for you to know the chinese bante plate is horrible. It takes half an hour to heat 50ml of water to boil and the stirrer is so unbalanced it will vibrate the contents off the plate in no time

Thanks for the heads up. On closer inspection I see that it is only 150 watts. When I get around to buying something I will get one with more oomph.

DrMario - 27-10-2014 at 02:56

Quote: Originally posted by Dr.Arz

Just for you to know the chinese bante plate is horrible. It takes half an hour to heat 50ml of water to boil and the stirrer is so unbalanced it will vibrate the contents off the plate in no time.

[Edited on 27-10-2014 by Dr.Arz]

Which ones are these "bante" hot plates? If you can link to a photo of one, that would help me a great deal.

j_sum1 - 27-10-2014 at 03:39

I think the one I linked to up thread.
http://www.sciencemadness.org/talk/viewthread.php?tid=41282&...

Dr.Bob - 27-10-2014 at 04:33

I am in the US, so these are 110 V, not helpful in most other countries. But there are other used ones on Ebay and other sites which come up, some are reasonably priced. Corning makes 220 versions, so that would be fine for most other countries.

DrMario - 27-10-2014 at 04:44

Not really: the only "reasonably" priced Corning hotplates are from US eBay sellers. The rest, which is very little, is unreasonably priced.

I just spent the better part of a quarter of an hour trying to find any non-US Corning hotplate on eBay. I came up with nothing.

DrMario - 27-10-2014 at 04:46

Quote: Originally posted by j_sum1

I think the one I linked to up thread.
http://www.sciencemadness.org/talk/viewthread.php?tid=41282&...

This one? http://www.ebay.com.au/itm/271274303830?ssPageName=STRK:MEWA...

OK, that's not the one I intended to buy.
But I will, I am almost sure at this point, get a cheap Chinese stirring hotplate eventually. There's a bit better choice of stirring hotplates from China on AliExpress.

adamsium - 27-10-2014 at 04:52

I have a 110 V IKA hotplate, although I am in Australia. I just use a stepdown transformer. I waited patiently (for a year or so) to get exactly what I wanted at a good price. I've found that, if you're patient, you'll find what you want for a very good price on ebay eventually. It was a similar story with my balance - that took a couple of years, but was well worth the wait. Both the hotplate and balance are much better than I need, but I see no problem with that

Edit to add: here is an example of the 'Bante' hotplates: http://www.ebay.com.au/itm/Brand-New-MS400-Hot-Plate-Magneti...

http://www.bante-china.com/Eng_Products_MS400%20Magnetic%20S...

I can say, from experience, that they should absolutely be avoided. I'd say the same is likely true for any of the cheap Chinese hotplates.

[Edited on 27-10-2014 by adamsium]

Ephesians - 27-10-2014 at 05:31

I have an extra magnetic hot stir plate manufactured by Corning Scientific if you are interested.

aga - 27-10-2014 at 11:14

Here's what I ended up after going through the same process as you :-

http://www.ebay.co.uk/itm/BUYLOWPRICE-Origin-New-hot-plate-m...

It's been able to do everything i've asked of it so far (mostly heating and stirring), and all-in-all i've been very happy with it.

I'm merely a noob though, and my requirement for appropriate temperature/stir speed remains at the level of 'is the stuff still in the pot or on the walls & ceiling ?'.

[Edited on 27-10-2014 by aga]

Lambda-Eyde - 27-10-2014 at 11:24

Ebay is flooded with the older IKAMAG models for great prices, which are supposed to be of great quality. Sadly, I haven't bought one myself yet.

Tungsten.Chromium - 29-10-2014 at 04:39

Wow, thank you guys for all the excellent replies, this has really changed my whole approach towards this purchase.

I've only been able to read through everything on my phone so fat so I've only skimmed this thread, but hopefully I'll get a day off work and can do some more serious review and research on what I really need. thanks again everyone

j_sum1 - 30-10-2014 at 04:42

Quote: Originally posted by Lambda-Eyde

Ebay is flooded with the older IKAMAG models for great prices, which are supposed to be of great quality. Sadly, I haven't bought one myself yet.

Found one! Great price!!

Um, er... postage???

DrMario - 30-10-2014 at 09:04

^^The seller probably uses UPS (AKA the crappiest, most abusive, most retarded shipping company in our cluster of galaxies).

Tungsten.Chromium - 6-11-2014 at 09:52

I ended up getting a used corning PC-351 off eBay for 175 (includes shipping). It looks to be in great condition by the pictures, and all my chemist friends swear by this model so I think I'll be content with it. Thanks again for all the help.

DrMario - 6-11-2014 at 10:27

Quote: Originally posted by Tungsten.Chromium

I ended up getting a used corning PC-351 off eBay for 175 (includes shipping). It looks to be in great condition by the pictures, and all my chemist friends swear by this model so I think I'll be content with it. Thanks again for all the help.

The quality should be top-notch. However, the fact that the temperature is adjusted from "LO" to "HI"... disqualifies this hotplate from an extremely large set of chemistry applications.

gdflp - 6-11-2014 at 10:32

Quote: Originally posted by DrMario

The quality should be top-notch. However, the fact that the temperature is adjusted from "LO" to "HI"... disqualifies this hotplate from an extremely large set of chemistry applications.

I don't necessarily agree with that. When I got my hotplate/stirrer, I spent extra to get a digital 10x10 ceramic one. I get a digital readout of what the temperature will be at that setting, but I don't find it all that useful. I think that a decent digital thermocouple could easily allow a Lo/Hi hotplate to be just as useful as a digital temperature prediction hotplate.

DrMario - 6-11-2014 at 11:15

Quote: Originally posted by gdflp

Quote: Originally posted by DrMario

The quality should be top-notch. However, the fact that the temperature is adjusted from "LO" to "HI"... disqualifies this hotplate from an extremely large set of chemistry applications.

Well of course! If you add a thermocouple or a Pt100 thermal sensor, and the regulation electronics to your hotplate then you have just created a wholly different hotplate.

Varmint - 6-11-2014 at 18:58

I have the Corning 420D, spent $410 to get it.

There are better, but at much higher price. There are "lesser" units that stir and heat, but are no where near as refined.

A purchase like this depends on your overall mindset. Do you appreciate undeniable quality? Are you likely to provide an amount of care a $410 purchase warrants, or are you likely to let decades of stains and spills bake on because tools do work and don't warrant care?

Me, I care. My near year old 420D has run (and is running right now in fact) for several hundred hours, yet in2 minutes or less I could clean up any dust that might have settled and any spills from this last run, and you simply could not tell it wasn't straight out of the box from the factory.

A little Bon-Ami cleanser or barkeepers friend every now and then will restore the ceramic surface to factory new condition. A moist microfiber cloth will clean the body, display area, and knobs, again, to factory new appearance.

And it looks very good with my genuine Corning Pyrex glassware on it.

Did I spend too much? I'm sure many people would think so. But I can turn it on and walk away and not have to wonder if sub-standard Chinese production or lack of care by it's previous owner is going to burn my lab down.

So, it depends on you. Does pride of ownership influence your buying, or, and I'm not trying to be disparaging here, is all you need a heater/stirrer?

Me, I like quality. I like knowing my equipment is not just up to the task, but probably better than someone of my qualifications/experience deserves.

DAS

[Edited on 7-11-2014 by Varmint]

NOV:5 - 6-11-2014 at 23:24

^^Well make that 2 of us.^^
I like my new or nearly new stuff. I hate that Hotplate nerdrage uses. It'd drive me nuts..
( Proud owner of a Corning PC-620D, and 6795PR temperature probe)

Quote: Originally posted by Varmint

I have the Corning 420D, spent $410 to get it.

There are better, but at much higher price. There are "lesser" units that stir and heat, but are no where near as refined.

A purchase like this depends on your overall mindset. Do you appreciate undeniable quality? Are you likely to provide an amount of care a $410 purchase warrants, or are you likely to let decades of stains and spills bake on because tools do work and don't warrant care?

Me, I care. My near year old 420D has run (and is running right now in fact) for several hundred hours, yet in2 minutes or less I could clean up any dust that might have settled and any spills from this last run, and you simply could not tell it wasn't straight out of the box from the factory.

A little Bon-Ami cleanser or barkeepers friend every now and then will restore the ceramic surface to factory new condition. A moist microfiber cloth will clean the body, display area, and knobs, again, to factory new appearance.

And it looks very good with my genuine Corning Pyrex glassware on it.

Did I spend too much? I'm sure many people would think so. But I can turn it on and walk away and not have to wonder if sub-standard Chinese production or lack of care by it's previous owner is going to burn my lab down.

So, it depends on you. Does pride of ownership influence your buying, or, and I'm not trying to be disparaging here, is all you need a heater/stirrer?

Me, I like quality. I like knowing my equipment is not just up to the task, but probably better than someone of my qualifications/experience deserves.

DAS"

[Edited on 7-11-2014 by NOV:5]

[Edited on 7-11-2014 by NOV:5]

jamit - 6-11-2014 at 23:43

@Tungsten.Chromium

try this hotplate on ebay: http://www.ebay.com/itm/Corning-PC-320-Hotplate-and-Stirrer-...

I love my pc320 by corning.

Stupid_Noob - 7-11-2014 at 01:37

I bought a cheapo stirrer/hotplate off ebay for $99 (haven't used it yet). I was wondering if there are chances of either the stirrer or the heating element going out during a distillation? Are these problems in cheap stirrers/hotplates?

I was under the impression that stirrers work by alternating magnetic field rather than a motor or what have you. Is it even possible for the stirrer to go out?

**EDIT**

Here's the link to the stirrer/hotplate. Trust me, the picture makes it look a lot less jank.

[Edited on 11-7-2014 by Stupid_Noob]

adamsium - 7-11-2014 at 05:53

I'm with Varmint. I will wait as long as I need to in order to find what I want for a reasonable price. As a result, I have an IKA RET control-visc hotplate, complete with temperature probe (purchased brand new for about $350, including shipping from USA to Australia) and a Mettler Toledo AX205 5-place balance, also purchased brand new for a tiny fraction of the list price (though obviously old stock as it is not the current model, but specs are essentially identical to current model as far as I am aware). Both are better than I'm ever likely to need, but I can live with that :cool: