gatosgr
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Lab equipment
Hey guys, I started this thread for us to post any lab equipment for a diy chemistry lab.
I've found this heater stirrer https://www.ebay.com/itm/85-2A-Magnetic-Stirrer-Temperature-... do you think it's good? I don't know if the thermometer probe is glass coated, if
it's not it's trash since temperature control won't work without it.
[Edited on 1-11-2018 by gatosgr]
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CobaltChloride
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It is way too weak at 300W. You're much better of buying second hand good hotplates stirrers from brand such as Corning, Fisher scientific, Thermolyne
etc.
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Sulaiman
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I have no idea how reliable the hotplate-stirrer that you pointed to is,
but it is popular so you can assume that parts will be available for a while.
/ waffle on __________________________________________________________
'which car (automobile) is best' ? ... 'horses for courses'.
I think that no matter what heating facilities we have,
a cheap generic hotplate is always useful,
so I suggest that you start with one.
After a while you will know exactly what you want.
(and after another while you will want something else again).
If you are already at this stage then;
I can imagine someone needing only that hotplate-stirrer for many years,
and others getting quickly frustrated.
For boiling water in a beaker to reduce volume or increase concentration,
or in a flask for for a distillation,
due to general heat losses, very roughly,
evaporated water ml/hour = Watts rating of heater.
e.g. a 300W hotplate would boil water off at 300 ml/hour ... roughly.
(Theoretically 300/2257 = 0.133 g/s. ... 478.5 ml/hour)
If jointed glassware is going to be used then I consider 300W to be
too much for 10/19 and too little for 24/29.
It depends upon what type of chemistry you want to do, and at what scale, and cost.
__________________________________________________________/ waffle off
[Edited on 1-11-2018 by Sulaiman]
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gatosgr
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Quote: Originally posted by Sulaiman  | I have no idea how reliable the hotplate-stirrer that you pointed to is,
but it is popular so you can assume that parts will be available for a while.
/ waffle on __________________________________________________________
'which car (automobile) is best' ? ... 'horses for courses'.
I think that no matter what heating facilities we have,
a cheap generic hotplate is always useful,
so I suggest that you start with one.
After a while you will know exactly what you want.
(and after another while you will want something else again).
If you are already at this stage then;
I can imagine someone needing only that hotplate-stirrer for many years,
and others getting quickly frustrated.
For boiling water in a beaker to reduce volume or increase concentration,
or in a flask for for a distillation,
due to general heat losses, very roughly,
evaporated water ml/hour = Watts rating of heater.
e.g. a 300W hotplate would boil water off at 300 ml/hour ... roughly.
(Theoretically 300/2257 = 0.133 g/s. ... 478.5 ml/hour)
If jointed glassware is going to be used then I consider 300W to be
too much for 10/19 and too little for 24/29.
It depends upon what type of chemistry you want to do, and at what scale, and cost.
__________________________________________________________/ waffle off
[Edited on 1-11-2018 by Sulaiman] |
Thanks for the info, I haven't found any other heater stirrers in this price range, the good brands's heater stirrers are located in the US and cost
double for them to be shipped to Europe where I am at right now. 
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Sulaiman
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Adding to your confusion, for a similar cost you can get a heating mantle with stirring
e.g. https://www.ebay.co.uk/itm/TOP-220V-Heating-Mantle-with-Magn...
but you would also require a stand and clamp(s)
and at least one flask, or a 'distillation kit'
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DavidJR
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A hotplate stirrer is a bit more versatile than a heating mantle though, so I'd get one of those first.
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VSEPR_VOID
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https://www.ebay.com/itm/500ml-Heating-Mantle-with-Magnetic-...
I want one of these.
Within cells interlinked
Within cells interlinked
Within cells interlinked
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gatosgr
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The mantles are good although I'm searching for s heater stirrer and I'll just use an oil or sand bath for the flask.
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gatosgr
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https://www.ebay.com/itm/SH-3-Hot-Plate-Magnetic-Stirrer-Mix...
[Edited on 6-11-2018 by gatosgr]
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j_sum1
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Sold Out.
(and does not post to oz. sniff.)
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Texium
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Thread Moved
6-11-2018 at 09:35 |
gatosgr
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found this for you
https://www.ebay.com/itm/Top-Plate-Magnetic-Stirrer-SH-3-Hot...
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j_sum1
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Thanks.
Here is my most likely option however: the best I can afford on this list: https://www.ebay.com.au/str/techido
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gatosgr
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Has anyone found a descent scale? Not a microgram scale. 1kg range.
[Edited on 7-11-2018 by gatosgr]
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Deathunter88
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Anything below 1000W will be pretty useful for boiling liquids/distillation. (IE things you want to be doing with a hotplate)
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gatosgr
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There's this one https://www.ebay.com/itm/SH-3-Hot-Plate-Magnetic-Stirrer-Mix...
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Sulaiman
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I have two cheap eBay small scales, 300g x 0.01g and 2000g x 0.1g
what ever type of digital scales you buy, they will need calibration.
High-end scales often have inbuilt standards,
the three 100g calibration weights for my 300g scales cost slightly more than the scales themselves,
my cheap 2kg scales are effectively useless for 'scientific' purposes as the required calibration weights are too expensive for me.
So, for 1 kg I suggest that you just use commercial or kitchen scales.
(unless you can afford the calibration weight or a regular calibration service)
P.S. As even cheap digital scales are reasonably linear,
and give repeatable performance for a period of time,
If all measurements are in weight, using one linear weighing device
then all relative ratios will be accurate,
This includes stoichiometric starting ratios of reactants, solvent ratios, product yield efficiency etc.
So if you only use one machine for weighing
and everything is measured by weight,
you can calculate results as if the scales were calibrated/accurate.
Using more than one measuring device invalidates the relationships / ratios.
[Edited on 10-11-2018 by Sulaiman]
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gatosgr
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| Quote: Originally posted by Sulaiman |
I have two cheap eBay small scales, 300g x 0.01g and 2000g x 0.1g
what ever type of digital scales you buy, they will need calibration.
High-end scales often have inbuilt standards,
the three 100g calibration weights for my 300g scales cost slightly more than the scales themselves,
my cheap 2kg scales are effectively useless for 'scientific' purposes as the required calibration weights are too expensive for me.
So, for 1 kg I suggest that you just use commercial or kitchen scales.
(unless you can afford the calibration weight or a regular calibration service)
P.S. As even cheap digital scales are reasonably linear,
and give repeatable performance for a period of time,
If all measurements are in weight, using one linear weighing device
then all relative ratios will be accurate,
This includes stoichiometric starting ratios of reactants, solvent ratios, product yield efficiency etc.
So if you only use one machine for weighing
and everything is measured by weight,
you can calculate results as if the scales were calibrated/accurate.
Using more than one measuring device invalidates the relationships / ratios.
[Edited on 10-11-2018 by Sulaiman] |
edit: thanks but how do you calibrate the scale from ebay, do the scales you've bought have a calibration function?
ok thanks for the info, the weight sensor is not very expensive the most common class is the one with 3000 divisions so for 3kg you have 0.1g accuracy
and for 300g 0.01g accuracy, it's not hard to build one with arduino and a HX711 load cell amplifier but it's not worth the trouble for a cheap scale.
this one goes up to 500g but I dont know what class load cell it has
https://www.banggood.com/SF-400C-500g-0_01g-Electronic-Balan...
[Edited on 20-11-2018 by gatosgr]
[Edited on 20-11-2018 by gatosgr]
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