Sciencemadness Discussion Board - HotPlate Branding

HotPlate Branding

Brightthermite - 13-7-2020 at 18:14

Hey all I am fairly new to purchasing actual chemistry equipment and just purchased the following hotplate.
https://www.amazon.com/Magnetic-Stirrer-100-1600RPM-Control-...

I have seen this exact same hotplate sold from 60-200 dollars. Im looking for tips and brands when purchasing equipment like this. Im sure most of these are all just branded Chinese hotplate. Trying to avoid purchasing expensive equipment that is a knock off.

Deathunter88 - 13-7-2020 at 18:17

Quote: Originally posted by Brightthermite

Hey all I am fairly new to purchasing actual chemistry equipment and just purchased the following hotplate.
https://www.amazon.com/Magnetic-Stirrer-100-1600RPM-Control-...

I have seen this exact same hotplate sold from 60-200 dollars. Im looking for tips and brands when purchasing equipment like this. Im sure most of these are all just branded Chinese hotplate. Trying to avoid purchasing expensive equipment that is a knock off.

Avoid any Chinese hotplates, that one probably won't even boil a liter of water (160W). Get a reputable one, such as from Corning, Fishersci etc.

Eddie Current - 13-7-2020 at 18:23

Quote: Originally posted by Deathunter88

Quote: Originally posted by Brightthermite

Avoid any Chinese hotplates, that one probably won't even boil a liter of water (160W). Get a reputable one, such as from Corning, Fishersci etc.

Agree. Spend the extra dollars when it comes to HP-stirrers. I paid $250 for a cheap Indian version and it taps out at 160C.........after taking 90 minutes to get there. It costs an extra $100 for one that is rated at 450C that would handle all hobbyist needs.

Syn the Sizer - 13-7-2020 at 19:12

Quote: Originally posted by Deathunter88

Avoid any Chinese hotplates, that one probably won't even boil a liter of water (160W). Get a reputable one, such as from Corning, Fishersci etc.

I 2nd that, I bought a cheap SH-2 model. It seemed decent until I had to heat something of a decent volume. On top of that even the slightest breeze would cool it down. Lots of wrapping in tinfoil. It lasted decent for the low price but just wasn't adequate. Also the magnetic stir function failed well before the hotplate itself.

G-Coupled - 13-7-2020 at 20:05

Quote: Originally posted by Eddie Current

I think I might know the Indian-made one you mean - are they kind of orange-brown, and is the $100 extra one the higher Indian model (which IIRC was 'digital' and had a decent power rating)?

[Edited on 14-7-2020 by G-Coupled]

Eddie Current - 13-7-2020 at 23:47

Quote: Originally posted by G-Coupled

Quote: Originally posted by Eddie Current

No, it isn't one of those, it's a REMI brand and it does have it's uses, but I just should have checked the specs a lot closer. It's useful for temperature sensitive heating with it's slow temperature adjustment.

Brightthermite - 14-7-2020 at 11:08

Quote: Originally posted by Deathunter88

Quote: Originally posted by Brightthermite

Avoid any Chinese hotplates, that one probably won't even boil a liter of water (160W). Get a reputable one, such as from Corning, Fishersci etc.

Im curious now to see if it will boil a liter. Are you purchasing straight from Corning or Fisher, because I see what I assume to be Fisher knock offs all over amazon.

Dr.Bob - 14-7-2020 at 11:28

This is junk. Buy a used Corning or similar one, it will have 4 or 5 times the heating ability and stir better.

Mateo_swe - 14-7-2020 at 12:27

Hotplate/stirrers is one of those items where a used, working good brand one is a better investment than a new low budget one.
The low budget ones work but have low heating power that make heating larger volumes very time consuming.
When you have used a good one you never want one of those cheap, slow units again.
Look at the heating power in watts when you compare different brands and models.

morganbw - 14-7-2020 at 14:44

They really need to have some wattage 600 watts or more a little under is okay but the wattage indicates how much it can heat.

Go with used name brands on the internet stores. I did and it worked out great. I did have to spend more than twice of what you did for a good stirring hotplate.

edit: added a word, deleted another.

[Edited on 7/14/2020 by morganbw]

B(a)P - 14-7-2020 at 15:28

This question seems to come up a lot on this forum and the answer is always the same, 'don't buy cheap/low wattage/unknown brands'. For the record I generally think this is good advice.
However, I think there is something missing and it might be a bit controversial.
I think that cheap low power hotplate stirers do have a place in the home/hobby lab

.
I own this or very similar. It will boil 1 L of water (on a hot day, wrapped in foil, with no breeze and maybe in direct sun

). The stirrer is not super powerful and neither is the hotplate, but it has lasted a couple of years with decent use (and abuse). It has withstood some pretty traumatic foam overs (for both me and the hotplate).
Would I use it to distil sulfuric acid, well no, but it is suitable for a great number of things.
You really need to think about what you are going to do. If it is low temperature, smaller volumes then why not go with something cheap and cheerful?
The other thing to consider is maybe a decent heating mantle is where you should invest your money.
Just wanted to put it out there that hotplate stirrers do not have to be able to boil 2 L of sulfuric acid if that is something you never intend to do.

Abromination - 14-7-2020 at 16:53

In terms of choosing a hot plate, it is important to select one with a watt rating of at least 600. This is enough to get well over a hundred degrees c. Those sh 1 models are awful and are hardly able to boil water.

@b(a)p, I had been under the impression that those were garbage.

[Edited on 7-15-20 by Abromination]

B(a)P - 14-7-2020 at 17:17

Quote: Originally posted by Abromination

@b(a)p, I had been under the impression that those were garbage.

[Edited on 7-15-20 by Abromination]

If you are working on the <250 mL scale and you don't need to go over 150C they are ok. For example I have used mine to go from acetylsalicylic acid to picric acid without issue.
If you want to work in larger volumes and at higher temperatures, yes they are garbage. My point is that they satisfy the needs of what I suspect is a good few hobby chemists.
I would conservatively guess that stirrer has done about 1500 h of work and it is still going strong.
I am not saying it is a good product, just that it does meet certain needs.

Edit - fixed a typo

[Edited on 15-7-2020 by B(a)P]

Mateo_swe - 15-7-2020 at 03:31

There is situations where those cheap hotplate stirrers can very well be used.
If you only do small volume experiments like max 500ml the cheap ones work and there is no reason to buy a hotplate with high heating capacity.
But if you have an hobby interest in chemistry and are going to do many experiments you will find that the 500ml limit will be too small real quick.
So the cheap ones arent useless but they are made for smaller volumes.
And often on ebay they write the hotplate can be used with larger volumes and they can, if you want wait hours before it starts boiling.

If you have some knowledge in electronics and electricity you can buy these heating mantle replacement sleeves on ebay.
They are the resistance heating wire put into glass fibre fabric.
They look like a nitted thing one can have on the head.
These can be driven with a variac or a dimmer circuit and are basicly a heating mantle without enclosure and electrical driver.
These work very good and are very cheap compared to regular heating mantles.
There are outlet voltages involved and one should have some knowledge about voltages and current before trying to connect them to a driver or variac.
Beeing electrocuted doesnt feel nice and can be the last thing you do so be careful if using these sleeves.
There are many videos on youtube about these.

[Edited on 2020-7-15 by Mateo_swe]

XeonTheMGPony - 15-7-2020 at 03:43

As others said never go by temp, go by watts first and foremost and any thing below 500 is going to leave you annoyed and frustrated a lot of the time (your average tea kettle is 1,500w to give you an example)

All ways well worth to save to buy a quality unit, think of it as a near life long tool, you want it to last as you grow to learn its unique quirks you can anticipate it

this really needs to be made into a sticky!

Mateo_swe - 15-7-2020 at 03:57

Someone should do a nice writeup how to make a DIY heating mantle of the replacement inner sleeves.
With a driver circuit and a stirrer function.
I think many would find this very useful.
From these i mean:
https://www.ebay.com/itm/2000ml-500W-Inner-Sleeve-use-for-2-...

2000ml heating mantle inner sleeve.jpg - 37kB

XeonTheMGPony - 15-7-2020 at 05:09

Quote: Originally posted by Mateo_swe

Someone should do a nice writeup how to make a DIY heating mantle of the replacement inner sleeves.
With a driver circuit and a stirrer function.
I think many would find this very useful.
From these i mean:
https://www.ebay.com/itm/2000ml-500W-Inner-Sleeve-use-for-2-...

I'm making a PID controller for my coffee tin mantles with an immersion probe.

Keftedes89 - 15-7-2020 at 05:46

I don't recommend buying Chinese. Not only will they not heat too high, but they don't last very long because of the more lax manufacturing laws and quality control. I'm all about buying used since the companies price gouge you for new ones.

I personally bought 3 from ebay from the same seller. Decent price and has quite a variety:
https://www.ebay.com/str/jpagora

B.D.E - 19-7-2020 at 21:53

Quote: Originally posted by Deathunter88

Quote: Originally posted by Brightthermite

Avoid any Chinese hotplates, that one probably won't even boil a liter of water (160W). Get a reputable one, such as from Corning, Fishersci etc.

second that. It's actually much much cheaper for the long run.
After buying 3 different Chinese plates that failed at one time or another, I finally decided investing in a used hotplate from Thermo Scientific. It's equvilant to a blind man first seeing colors.

Brightthermite - 20-7-2020 at 11:58

So far the hot plate has worked alright. The plate temp reaches the max temp of 350 C as advertised but can not hold it with any sort of load applied (just doesn't have the power). As others have said this cheap one does work very well for my purposes but if i could go back and spend the extra 70 dollars on one that would work well for ALL purposes I definitely would. I appreciate all the help guys!

B(a)P - 13-7-2022 at 16:50

Quote: Originally posted by B(a)P

This question seems to come up a lot on this forum and the answer is always the same, 'don't buy cheap/low wattage/unknown brands'. For the record I generally think this is good advice.
However, I think there is something missing and it might be a bit controversial.
I think that cheap low power hotplate stirers do have a place in the home/hobby lab

.
I own this or very similar. It will boil 1 L of water (on a hot day, wrapped in foil, with no breeze and maybe in direct sun

I thought it was worth providing an update on my hotplate, image provided for context. I recently had an ammonia generator set up using sodium hydroxide and urea. I had a foam over and the hotplate got covered in hot sodium hydroxide solution and it caused some serious damage. Much of the paint of the housing started to peel and the metal underneath corrode and because of the construction of the plate some of the solution got into the working parts. The wire which attaches to the heating element burnt through and needed repair. I was surprised by the construction of the element. It consists of a single strand of hair fine nichrome wire, see attached image. I have managed to get the hotplate working again, but with the substantial corrosion to the housing I doubt it is long for this world.
So, my hot tip - If you are going to go for a cheap hotplate stirrer, try to get one where any spills or overflows do not go straight into the electronics.

Edit - It is worth noting that the manner in which the unit failed essentially had the external housing live at 240 V, until the fuse blew. This occurred because the wire attached to the element fell away once it burnt through and rested with bare wires against the internal of the housing.

[Edited on 14-7-2022 by B(a)P]

Lion850 - 13-7-2022 at 17:35

I use the same brand hotplate as shown in the link of the original post a few years back, but the SH3 model which is a bit more powerful.

The first one lasted 9 months or so and died when a beaker broke and a concentrated solution of nickel nitrate ran into its guts. But by then I was sufficiently happy with the value (performance vs price) that I ordered the same SH3 from the same supplier, I think it was around AUD 120 on eBay.

When the second one arrived the stirring was intermittent out of the box and often not working at all. I informed the supplier and he proposed a refund of AUD 100 and I keep the faulty unit, or I send it back to China at my cost and they then refund the full AUD 120. I took the 100 and kept the unit. Once I had the refund I opened the unit and found a loose connection in the stirring motor wiring which fixed the issue. And it has not missed a beat since (some 18 months).

One just have to avoid spillage with these as the design allows the fluid to enter the unit. Poor design, a small change to the actual top cover plate would have preventer this.

I think if one gets a year life out of something like this it is worth the low purchase price.

PirateDocBrown - 14-7-2022 at 03:16

I got one of those SH-2s also. The stirrer works great, the heat is weak. So, if I just want something stirred and kept warm, it's fine. I go elsewhere for higher heating.

My theory is that they are actually 230v, and the manufacturer just slapped a US plug onto it, so it only gives quarter power. P=E^2/R

Chemgineer - 16-7-2022 at 07:38

I have an ANZESER SH-2, the heat is great but after it's been hot you find the magnets have lost their strength, I bought a stack of neodymium magnets to replace them but they don't last long.

You may be correct on your 230v theory as i'm running mine from 230v.