Sciencemadness Discussion Board

Mini- (or micro-) hot plate / stirrer

Keras - 27-5-2024 at 11:08

Folks,

does anyone know about very compact/portable hot plate/stirrers, typically for microscale experiments? Say, max 10x10 cm. It seems Ohaus made one but has been discontinued. Some Chinese producers have references (Vevor, Joanlab), but I’m not sure how reliable they would be.

Any hint would be greatly appreciated!

j_sum1 - 27-5-2024 at 17:46

For small scale stuff, I have made good use of a stirrer made from a computer fan with some neodymium magnets stuck on. I once had a lump of metal in a test tube stirring for a week to dissolve it.
Addition of a heat gun can give you the heating.

Here is a cheap idea for a small hot-plate:

soldering pot.jpg - 6kB

These soldering pots are pretty cheap to buy and occasionally very useful.

Or, you can just use a large hotplate-stirrer. It will take up some bench space, but with a suitably sized stir bar and an oil bath to stabilise the temperature, I don't think there should be many real problems.

Keras - 27-5-2024 at 21:29

Well using a large stirrer is somewhat clumsy. To have good stirring you must centre, say, the RBF on the stirrer. But then my microscale glassware is so small the whole distillation set can easily fit on the plate (the RBF must be 2 cm wide, and the condenser maybe 6/7 cm long). So I end up with the whole set hovering over the heat source, which is far from ideal.

Sulaiman - 28-5-2024 at 01:45

For my NS10 (ST 10/14) kit I sometimes used an IKEA tealight candle,
produces about 35W of heating power - if you don't need stirring.
A small spirit lamp can give a cleaner and/or hotter flame, but I need to make a new one.

PS I also have two of the solder baths that j_sum1 gave a picture of.
One 100mm dia. and one 38mm (from memory) dia.
Both useful for oil baths.

I have no stirring option at this scale, yet.

[Edited on 28-5-2024 by Sulaiman]

Keras - 28-5-2024 at 12:25

I think I’ll test the mini (12x12) hot plate / stirrer made by Vevor. It’s Chinese, but at ca. 50 € price point, if it breaks down quickly, my bank clerk won’t hold me a grudge for long.

bnull - 28-5-2024 at 14:50

If it breaks, you can either fix it yourself or use it to house a new circuit. Not bad.

ManyInterests - 28-5-2024 at 16:50

I have a small hotplate stirrer. It isn't very good and I regret buying it. But it depends on what you want to accomplish? What kind of experiments are you looking to do? How hot do you want things to go? How much (in ml) are you trying to go for?

Keras - 28-5-2024 at 22:49

All kind of things from refluxing to distillation. The max. capacity of the glassware is 25 mL.

OOPS! instead of 10/14 I should have written 10/19

Sulaiman - 29-5-2024 at 07:51