Sciencemadness Discussion Board

Hotplate/Stirrer

Maja - 4-1-2007 at 06:29

I have no hotplate/stirrer combo and I would like to obtain ,because after some time I saw that it's really good and neccessery thing in lab. I saw a lot of hotplates on the net... I don't know which one is good. Can you suggest me from your experience ? And it would be very kind from you that you link me to some shops... Thanks.

The_Davster - 4-1-2007 at 08:37

I would advise against one of these: http://www.sci-support.com/images/300/1076.jpg

Unless of course you like to dissassemble your equipment and alternate between tossing parts in a fire and quenching in water.

Something with an all metal plate up top is my favorite. Check the usuall places, Ebay, LabX

Magpie - 4-1-2007 at 09:55

Maja I really like my Corning PC-320. It has a ceramic top that measures 6" x 7.5". It has never given me any trouble. I bought it on ebay for $138.

conducter - 4-1-2007 at 10:42

this is the one i am thinking of getting.

http://discountlabs.com/catalog/product_info.php?products_id...

Maya - 4-1-2007 at 11:20

Any one you can get cheap and works is good since they are all the same no difference in operation or quality , under $60 is good , look for used otherwise you'll pay a fortune

conducter - 4-1-2007 at 11:43

damn maya, invite me to this world where one can get a good hotplate/stirrer for under 60! sounds like a dream world

Maya - 4-1-2007 at 12:30

They are around if you know where to look ( hint, hint )

Maja - 4-1-2007 at 12:35

Oh, I have just noticed you Maya :) HI !
Thanks The_Davster and Magpie for suggestions

What do you think about this one http://www.bestlabdeals.com/Fisher_Isotemp_Aluminum_Top_Stir... ? I can spend about 300$ on that...


I bought that one :



But it burned after a few days i got it from ebay, I paid 50$ for this one and 50$ for shipping... It was kinda sad :( So I don't want to experience same thing one more time.... How about thermolyne ? Is it worth that money ?

Maybe someone knows supplier in Europe ? So shipping costs won't be so high to my poor country :( ? What are your recomendations on hotplate size ? What size is most optimal ? I think the bigger the better ?

[Edited on 4-1-2007 by Maja]

Maya - 4-1-2007 at 12:37

That's not a brand I've seen B4, my Fav is corning.

did you burn it out mechanically or thermally?

Usually these things aren't really meant for much more than 100 deg, If I need >100 deg I go to a mantle between the stirrer and the RBF

[Edited on 4-1-2007 by Maya]

Maja - 4-1-2007 at 12:43

No, they stated that this hotplate could be used at 350*C.... My electric sockets puts out 220v .. So I need 220v hotplate. All American brands I saw before was 120v... :/

mrjeffy321 - 4-1-2007 at 13:10

Quote:
Originally posted by Magpie
Maja I really like my Corning PC-320. It has a ceramic top that measures 6" x 7.5". It has never given me any trouble. I bought it on ebay for $138.

Like Magpie, I too have a Corning PC-320 hotplate-stirrer which I purchased used on eBay (for about $100). I am extremely pleased with my purchase. This hot plate is very durable...it took a Sulfuric acid bath and survived to tell the tale.

Maja - 4-1-2007 at 13:15

I used to hear from my friends that corning brand stirrers isn't good... What's the maximum volume of sirupy liquid(conc sulfuric acid for example) they can stir heavily ? Suggest something :) I want to buy one as fast as I can :) By the way ... What's differences between PC 420 and 320 ? I can buy PC420 for 125$. What do you think ?

[Edited on 4-1-2007 by Maja]

conducter - 4-1-2007 at 14:55

i already have a hotplate that works amazing, is there any way to fuck with it to make it into a stirrer as well?

Hilski - 4-1-2007 at 18:24

Quote:
i already have a hotplate that works amazing, is there any way to fuck with it to make it into a stirrer as well?

Similarly, I have a good Corning stirrer, and I need to find some sort of hotplate that I can set on top of it and still have the stirrer work properly. Heating mantles work, but sometimes one needs to use an oil bath. Anyone have any suggestions for some type of hotplate that I can use to heat an oil bath, that I can use on top of a ceramic-top stirrer?

turd - 5-1-2007 at 02:39

Quote:
Anyone have any suggestions for some type of hotplate that I can use to heat an oil bath, that I can use on top of a ceramic-top stirrer?

Why not just put one of those heating coils in the oilbath?

MargaretThatcher - 5-1-2007 at 16:51

I recall Nicodem using some functional but dangerous looking string of power resistors as an oil bath heater. A suicide chain, I believe they are called. Be OK if you use an isolation transformer or earth-fault breaker.

Hilski - 6-1-2007 at 08:39

Quote:
I recall Nicodem using some functional but dangerous looking string of power resistors as an oil bath heater. A suicide chain, I believe they are called. Be OK if you use an isolation transformer or earth-fault breaker.

What thread was that in? I'd be interested in knowing how well that type of setup would work.

microswitch - 19-1-2007 at 20:52

This seems like a good area to ask, which is better heating mantle or plain flat bottom flask? Whats the difference? It seems like flat bottom glassware would be easier to work with, etc.

bio2 - 19-1-2007 at 20:59

......What thread was that in? I'd be interested in knowing how well that type of setup would work.........

Don't know the thread but a better way is to get an aluminum sheathed immersion heater, expand the coils to fit your oil bath.

I have a one coil 400watt and a 1KW two coil one that work great on the stirrer. Much less wattage needed than using the
hot plate top.

[Edited on 20-1-2007 by bio2]

microswitch - 14-2-2007 at 17:46

I just got a Cimarec hotplate/stirrer.

Question: Everyone should know by now water boils @ 100 degrees C right? Well... the hotplate stirrer seems to take forever to boil water in a erlynmeyer flask even if I set it to 280 degrees C. :(

Im not that high up elevation wise, 312 feet above sea level to be exact. So what gives? Am I just not used to how long it takes a ciramec top to heat water or what? Im afriad my unit may be defective (if so yikes cause I sure paid a lot for it)! :mad:

DeAdFX - 15-2-2007 at 00:27

Quote:
Originally posted by microswitch
This seems like a good area to ask, which is better heating mantle or plain flat bottom flask? Whats the difference? It seems like flat bottom glassware would be easier to work with, etc.


Heating mantles I think are better in my limited experience. They heat a majority of the flask. Then you can cover the top part of the flask with some insulation so the heat stays in. With a flat bottom on a heating plate your heat is going to escape. Of course you could place the flask in a beaker with oil but in this case you have to worry about a flammable liquid. I don't know if I am exaggerating the efficiency of the heating mantle or not but it is the best ~300usd I spent[mine also comes with a stirrer thing which kicks butt].

In my way of chemistry I find that having the right piece of equipment for the job is essential to a successful experiment. I generally dislike improvising.

Drone - 15-2-2007 at 03:01

Microswitch,

From my experience your hotplate sounds fine.

The temperature set on the dial is acheived on the surface of the hotplate. There are significant losses from the hotplate surface to the flask.

This tends to be useful if you are trying hold something at a steady temperature, but getting things to temperature from cold takes a while.

jackson2004 - 24-6-2007 at 19:03

I got my hotplate stirer from ebay, it only cost me a tenner in GBP ( $20 ), its old but who cares for a tenner. It works

bio2 - 24-6-2007 at 20:39

.......Similarly, I have a good Corning stirrer, and I need to find some sort of hotplate that I can set on top of it and still have the stirrer work properly. Heating mantles work, but sometimes one needs to use an oil bath. Anyone have any suggestions for some type of hotplate that I can use to heat an oil bath, that I can use on top of a ceramic-top stirrer?............

Another idea I have used to heat a 6L flat bottom flask on a ceramic top stirrer/hotplate is to use one 330W element from a toaster sandwiched between thick asbestos paper. placed
on the ceramic surface.

This actually heats the flask quicker and easier than the
1600W element embedded in the 12'X12" ceramic top and
the stirrer works fine thru the flat ribbon NiCr which is wound
on a mica sheet.

Kiakin - 5-8-2008 at 08:27

Hello all. I've been lurking around for a while but it's time to register since I need your help :)

Like the original topic starter I would also like to purchase a good hotplate/stirrer. Which would be the best surface material ? I've heard that Fisher is a very good brand ?

I'm also wondering if anyone had any experience with this kind of hotplate/stirrer or knows where they can be bought ? Or just the reaction block if a combo isn't a avaliable. The reaction block would make heat transfer as good as a heating mantle, IMO.

[Edited on 5-8-2008 by Kiakin]

[Edited on 5-8-2008 by Kiakin]

20070047387-0-display.jpg - 30kB

grndpndr - 17-8-2008 at 20:14

Being extremly low buck ive used air agitation from a set of aquarium air condensers and glass tubing output into the beaker etc to provide a mild stirring action where several hours are involved this has woked satisfactorly for me in several applications with ccaisonal hand strring.The introduction of air to some synthesis isnt advisable but for my needs has been adequate as the air pumps cost me$ 0.Crude ,absolutely! but when on a budget the outcome is the point not sophistication.HAve also used this low buck approach for homemade nitric acid distillation with occaisonal need to replace some components but fully fnctional with minimal investments producing 95%+ nitric acid depending on sulfuric acid concentration.Im all into making a minimal footprint from equipment to precursors.FWIW.:D

Picric-A - 17-8-2008 at 23:35

i found this on ebay, i dont live in america and so i wouldnt want to buy it however i thought it looked quite a good deal, 3l rbf and mantle...
http://cgi.ebay.co.uk/308-Value-Glas-Col-Heating-Mantle-3L-P...

TDCFMOG - 3-9-2008 at 23:21

Quote:
Originally posted by Kiakin
Hello all. I've been lurking around for a while but it's time to register since I need your help :)

Like the original topic starter I would also like to purchase a good hotplate/stirrer. Which would be the best surface material ? I've heard that Fisher is a very good brand ?

I'm also wondering if anyone had any experience with this kind of hotplate/stirrer or knows where they can be bought ? Or just the reaction block if a combo isn't a avaliable. The reaction block would make heat transfer as good as a heating mantle, IMO.

[Edited on 5-8-2008 by Kiakin]

[Edited on 5-8-2008 by Kiakin]


Chemglass sells it for their hotplate/stirrer.

OptiTherm® Reaction Block, Round Bottom

Also

PIE-BLOCK, Reaction Block

[Edited on 4-9-2008 by TDCFMOG]

Hot plate stirrer

tapira1 - 6-9-2008 at 17:44

My preferred hot plate stirrer is the Nouva II. It is old fashioned, but stirring is superb and reproducible, starts heating at 37ºC, is affordable and heating block can be placed atop with good results. The only con: It is too "bulky".

grndpndr - 19-9-2008 at 22:24

Is there a place/category for Homebuilt hotplate /agitator?
That works by virtue of vibrating a$12 coil hotplate attached to a 1/2 in. ply base using 2 vibrators liberated from an old massaging chair.Tryed to get some from whorehouse in deadwood motel bed but no luck.Anyway the 2 electric vibrating assemblys are mounted
through rubber attachment points to reduce noise on either side of the hotplate which is also attached to the ply with rubber isolators again to reduce oberved noise while still allowing the vibrating agitation to act on the hotplate beaker
and of course its 2 speed as the vibrators are seperately operated.beats heck out of constant stirring but is definetly NOT a magntic stirrer but it d0es mix hell out of things.As my lab is the out of doors indoor synthesis and wifes opinion and children dont mix well from the wifes standpoint and i admit Im forced to agree.To that end assembly of the components is restricted to small easily moved /set-up component parts.

The beaker/glassware is prevented from vibrating off the hotplate by the wire mesh attached to the heating coils by individual wires cut and fitted from the mesh cover the remainder f the mesh covering bent up to prevent the beaker etc from vibrating off the hotplate.



[Edited on 20-9-2008 by grndpndr]