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highpower48
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Chinese Hotplate/Stirrers
Has anyone tried the $100.00 Chinese Hotplate/Stirrers? Are they worth the price?
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Corrosive Joeseph
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Maybe a link or two might be handy..........................?
/CJ
Being well adjusted to a sick society is no measure of one's mental health
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highpower48
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Will do so when I get home. Phone app does not give me a url.
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JJay
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If it's the 85-2 stirrer, I wouldn't recommend it for chemistry, although it's not so bad if you just want to stir a fermentation mixture, work with
ether, or keep an electrolytic cell at a certain temperature. I could see it as being useful to brewers or perhaps in medical or bio laboratories. If
it had a ceramic top, a more powerful heating element, and better documentation, as well as a thermostat that goes to 350 C, I could see it as being a
lot more useful. There are a lot of things I like about it, but I just can't recommend a hotplate that won't boil water to chemists.
I haven't tried the 85-2A stirrer, but I am curious about it.
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highpower48
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Look at this on eBay http://www.ebay.com/itm/232092408590
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JJay
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It's only 180 watts... that's really not very powerful.
I'd just get a used Corning PC-351 or PC-320 (or something similar).
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Geocachmaster
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Quote: Originally posted by JJay  | It's only 180 watts... that's really not very powerful.
I'd just get a used Corning PC-351 or PC-320 (or something similar). |
I think this is a great idea. I ordered a used Corning PC-351 on Monday and it arrived today! I got it along with 8 stir bars for ~$120, so it's not
that much more expensive. I've tested it a bit and I love it already. Worth every penny
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diddi
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the chinese one I bought had a nice digital readout and looked great. when I used it the first time, it literally melted and nearly caused a fire.
lucky I was checking on it regularly. now I have a good one tf and it works perfectly every time. and not a chinese brand either
Beginning construction of periodic table display
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PirateDocBrown
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I got one under the tree this Christmas. Haven't tried it out yet.
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PirateDocBrown
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Seems to heat OK, but at 180 watts, it's gonna struggle to boil even a liter beaker of water. The stirrer is fine. It came with a stirbar, too.
The thermometer stand is useful.
Nothing at all wrong with it, it's just small.
How long it lasts, only time can tell.
[Edited on 2/1/17 by PirateDocBrown]
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Melgar
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It's probably designed for 220 volt systems, and made for the rest of the world aside from the US, Canada, and Japan. Since P = VI and V = IR, then P
= (V^2)/R. When you divide V by 2, that divides power by 4, and multiplying V by 2 multiplies power by 4. So a 180 watt resistive heating element at
110 would output 750 watts at 220, a much more reasonable number.
However, these could also be ones that didn't pass quality assurance for the heating element, but would be okay to run at half the voltage they were
initially supposed to run at. So if money is tight for you, don't go looking for ways to boost the AC voltage or anything.
I actually used this to my advantage when building a still in college. You needed to first heat up room temperature water to boiling, then collect it
from the top. At 1000 watts, it took FOREVER to boil, so I bought a 220 volt, 4000 watt hot water tank heating element. I'd plug it into the dryer
outlet (220 volts) until it was boiling, then switch to a 110 outlet for collecting. It'd be easy to get one now, but it was hard to find 220 volt
TRIACs back then.
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18thTimeLucky
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I thought I would invest in a hotplate stirrer as it is starting to be painful to not have one; a spirit burner can only do so much.
As this will be my first hotplate/stirrer and I am poor as crap, I was wondering if any of you beautiful people could recommend me cheap hotplate
stirrers that are still quality enough to heat sufficently and not break within the first 30 seconds.
£100 is my maximum budget really but maybe this is unreasonable and I will have to accept the fact that I will only have some dirt and the hotplate
stirrer to my name after purchasing it.
I had looked into the 85-2 and the SH-2 as they were the cheapest on eBay (within £40-£60) and are sold by multiple sellers. It was interesting to
read on this thread they are probably not worth the money anyways. The SH-2 says it can manage a maximum temperature of 380oC although what
I have understood is despite that, being 180 Watts it would take a million years to heat up?
http://www.ebay.co.uk/itm/1000ML-Magnetic-Stirrer-Mixer-Mach...
http://www.ebay.co.uk/itm/Magnetic-Stirrer-With-Hot-Plate-He...
Would it be worth to bite the bullet and buy a more expensive second-hand hotplate from a good quality brand name?
Any answers would be appreciated!
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Melgar
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If you have more time than money, you can build one from the base of an electric kettle. I hear those are quite popular in localities where pounds are
a unit of currency. Hair dryer fan motors are excellent for stirring too, you just need to mount a permanent magnet to the shaft and figure out how
to control it.
The first step in the process of learning something is admitting that you don't know it already.
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18thTimeLucky
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That is actually a very good idea, I had not really considered making one. I am not fantastic with electronics but I have a friend who is so maybe he
can lend me a hand.
Hotplates without stirrers seem to be quite cheap, I found a 1500W for £20, so I might purchase a hotplate and build a stirrer; I heard computer fans
can do the job quite well too when building a stirrer.
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Reboot
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Hello!
In my experience the way these thing usually work out is that you tinker, play, and end up not really saving much money for what turns out to be an
inferior product. The process is interesting, it's fun, it's educational. On the other hand, if you really just want a decent, reliable
hotplate-stirrer, you're probably better off saving up and buying something ready-made.
I'm not sure how things are on your side of the pond, but here in the states, the going rate for a good used (modern, in decent shape, quality brand)
hotplate-stirrer is around £150.
For me the big 'quality' indicator is heating power. I look for something around the 500-700W range, which is enough for small-scale heat-hungry
distillations. If it has that kind of power, the stirrer is probably well-built too.
Electronic controls and displays raise the price, of course. I feel a temperature setting readout and an option for a temperature probe is worth
getting, but your milage may vary. Personally I don't see any real value in an RPM readout (usually 'as fast as it goes without destabilizing the
stir bar' is the right setting for me. :-)
I like physical knobs. Up/down buttons to (for instance) change temp settings are easy to manufacture, but they seem awkward to me.
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18thTimeLucky
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I think it would be a fun project to make a stirrer anyways but I will take it from your experience that this is not necessarily the best route in my
situation.
I am by far not a experienced amateur chemist so I am not familiar with hotplate stirrer prices, even here in the UK, but I considered your advice of
a 500-700W range and I found a few reasonably priced products on eBay and I was wondering if I could have an opinion on them. The page and the whole
specifications can be found by the links and they seem to be trustworthy sellers. Thank you!!!
http://www.ebay.co.uk/itm/SH-3-Hotplate-Stirrer-17x17cm-Anod...
£86.88
SH-3 hotplate stirrer: 500W: 220V: maximum 380oC: 100-2000RPM: stirring capacity 3L: no warranty
http://www.ebay.co.uk/itm/HOTPLATE-STIRRER-STIR-HEATER-MIXER...
£119.99
GLTlab hotplate stirrer: 500W: 220/240V: maximum 450oC: 50-2500RPM: stirring capacity 10L: 2 year warranty
http://www.ebay.co.uk/itm/220V-Hotplate-Magnetic-Stirrer-SH-...
£145.00
SH-4 hotplate stirrer: 600W: 220V: maximum 380oC: 100-2000RPM: stirring capacity 5L: 1 year warranty
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Σldritch
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I just bought the last one (SH-4 ceramic). Trying to distill a liter of water right now in a sand bath but it does not seem to work. I think these
hotplates are pretty pathetic heating wise but that is not much of a problem if you have a burner too.
Ill try without the sand bath and update.
If you are in US i think an used corning hotplate stirrer would be better.
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18thTimeLucky
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I would be very interested to know how that goes for you. Please do provide an update! That is unfortunate if you find it to not be heating properly;
hopefully you can speak to the seller and get a refund if this is the case. If not at least we can be pretty confident in not trusting that seller or
brand in the future. It does have a 1 year warranty though.
Lets hope it was just the sand bath that was being slow.
Buying hotplate stirrers seems to be a needlessly tricky business!
[Edited on 24-8-2017 by 18thTimeLucky?]
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Reboot
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I would avoid this one. The (inexpensive) aluminum surface will be pretty vulnerable to corrosion from chemicals. Since it's not a 'proper'
material for a chem lab, it makes me wonder how well-made the rest of it is.
Looks like a very basic, even primitive design, but a ceramic top (or stainless) is appropriate and I like the weight of the unit. (Physically light
hardware tends to be an indicator of low quality when it comes to these things.) Probably a solid contender.
I would lean towards this one of these three. The case is clearly more expensively manufactured than the previous unit (a casting instead of bent
sheet metal), which tends to be a good quality indicator. The built in rod holder is a small detail but it can be a handy convenience (even with a
flat bottom flask an assemblage of glassware can get quite tippy!)
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Mush
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SH-2 model does the job surprisingly well. It's adequate to small volumes about 100-200 mls. Larger than that one would need a bit more powerful
hotplate.On maximum power , 150 °C can be reached (in the reaction flask) with 500 ml oil bath in a pyrex dish. Excellent for home usage even for
school labs. For very pro use go for something else. I would say price /value is 7/10. After 7 month, 6-7 h a day use, still works.
[Edited on 26-8-2017 by Mush]
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18thTimeLucky
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I'm so confused what hotplate stirrer to buy! I don't know whether to make one, buy a cheaper one, or go for a moderately priced one. I am by no means
unthankful; I really appreciate all the help!
I might think about going for the SH-3 model. Mush, you said from experience(?) the SH-2 is excellent for most small scale reactions, and Reboot, you
said the SH-4 seems to have good quality indicators so although you said the SH-3 has got lower quality indicators it is a similar model (SH) and my
poor wallet can only dream of owning even the SH-4. When I have more money in the future and my cheapo hotplate stirrer kicks in I can afford a more
expensive, higher quality hotplate stirrer.
I will think about the GLTlab hotplate stirrer as it does seem a solid contender as you said (also I love the 2 year warranty). I hope Σldritch gives
us a update about the SH-4 as that will help make a decision whether the SH series is potentially good quality.
Again thanks so much for all the help, I have only been an amateur since December last year and I am studying chemistry at A-level and in a year at
university and I wish I had found this gold mine of a forum sooner! I look forward to contributing and helping others too when I have the opportunity!
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Σldritch
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Late update: i tried distilling water with my SH-4 by just thoughing the 1 liter RBF to the hotplate. It does distill then and i could probably
increase the temprature it can distill at by adding some sand around the RBF. The stirring works great unless you have some metal between like a steel
pot.
I wouald have bought a used corning but in the EU i could not find anything this cheap. It might not be the best (it really isnt) but with a burner i
think it works; you are not going to use a magnetic stirrer anyway at around 300C.
So i guess i recommend it if you are looking for something really cheap which was also the reason i bought it. If you can find anything better in the
same price range it is probably better but used cornings and such hard to come by in the EU. Also there is a one year warranty which is reassuring.
[Edited on 27-8-2017 by Σldritch]
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Melgar
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| Quote: Originally posted by Reboot | | I would avoid this one. The (inexpensive) aluminum surface will be pretty vulnerable to corrosion from chemicals. Since it's not a 'proper'
material for a chem lab, it makes me wonder how well-made the rest of it is. |
I used to think that too, until I realized that it takes a ridiculous amount of time for acid to dissolve through aluminum that thick. Try putting a
piece of aluminum wire in straight HCl and time how long it takes to dissolve. I bet it's longer than you expect.
There's actually an element of safety built into using aluminum as well, believe it or not, since if you're not paying attention, and a vessel
overflows, you can hear it immediately.
I can't tell you how many times I spilled corrosive chemicals on the surface of my last hotplate, which was aluminum. But after all those years of
abuse, the deepest anything ever ate into it was only about 1 mm.
If you want to build a hotplate, make sure to get something with a circular heating element, so you can put the stirrer magnet in the middle of that.
Also, go beat the piss out of whoever told you that computer fans make good stirrer motors. They're MUCH too weak. However, if you take apart an old
printer, you'll probably find at least three DC motors that could do the job.
The first step in the process of learning something is admitting that you don't know it already.
I'm givin' the spam shields max power at full warp, but they just dinna have the power! We're gonna have to evacuate to new forum software!
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SWIM
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There are some hotplate stirrers on the market that are even cheaper than the sh-2, but are rated at 300 Watts.
The Bipee 78-1 can be had on Amazon for $74!
Why so cheap? the stirrers has a speed control, but the heating element is an on/off situation with no rheostat.
I don't know how reliable Bipee products are, but it should be a breeze to wire an external dimmer switch to the part of the circuit that powers the
heating element. There's a separate on/off switch for the heating element that you could replace with a jack to plug in a rheostat.
Then you'd have some extra wattage, a stainless steel heating surface, and decent power control for less than $85.
And If you ever burned out the rheostat you wouldn't have to worry about finding a replacement that fits in the casing.
Just go to your local hardware store for another cheap dimmer switch.
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18thTimeLucky
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It has been a few months now so I thought I would return to this topic in case anybody finds themselves in a similar situation.
I ended up buying the hotplate stirrer from this link from eBay:
https://www.ebay.co.uk/itm/HOTPLATE-STIRRER-STIR-HEATER-MIXE...
Since I mentioned it before the price has dropped by £10 to £110. I ended up buying it when it was £120 but payed £110 anyways due to an offer I
made to the seller.
The only thing I can really complain about the hotplate stirrer is that the specification was off when comparing what I received to the sellers page.
For instance, the heating power is said to be 500W but in fact what I received had written in the instructions manual that it was 400W, and a few
other things like that.
Other than that though the stirring function worked great, I have never needed to turn it up higher than half way to full power. The heating works
fine too, it can easily get above the boiling point of water and seems really fast with volumes around 200ml. I do not know how hot it can get, but I
have so far never needed to continually use the full powdered heating. The product also arrived very quickly - within a few days if I remember
correctly.
I have not really stressed it, just used it for things like distillation of propan-2-ol, evaporating water from a sodium ethanoate solution, general
stirring etc.
On top of the two year warranty I would thoroughly recommend this as a hotplate stirrer though if you are looking for something new, cheap and
functional.
Yep, I have a chemistry blog!
18thtimelucky.wordpress.com
"Amateur chemistry does seem like being in a relationship with someone very beautiful and seductive but has expensive taste, farts a lot and doesn't
clean up after themselves, but you love them anyway" - a dear friend |
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