Recommendations for stirrer / hot plate units?
I've looked at some of the used hot plate / magnetic stirrer units on eBay, but I'm kinda overwhelmed by all the choices, and also what options and features I'm looking for.
Anyone here an expert on these things? Can you recommend a unit that is on the cheaper side of things? I would like to spend under $100.
I have a NuovaII by Thermolyne. It doesn't have a heater and I doubt you will need one unless you need to control the temperature over a long period of time. The supporting surface is 7"x7" and I use a 2-1/2 gallon plastic pail for all my mixing. I'm confident that a mixer with a smaller support surface would work as long as I added outside support for the mixing container so even a relatively small (and usually cheaper) stirrer will work for you. I'll bet you can get away with less than $30 without a heater.
I only mix Dektol, Xtol and Kodak HCA, but it is really convenient to turn it on low and walk away. Order a stirring bar at the same time as most on ebay don't have them included.
One the cheap side, I have made a DIY approach.
I think my basic stirrer, at least 40 years old, and found used in the basement of my favourite photo dealer for something like $40 a few years ago, would be a good start.
I then picked up a commercial Bunn type coffee warmer used at the thrift store, and took the 300W nichrome heater core in sleeve, and the bracket used to originally hold it to the underside of the carafe area, and transferred them to the underside of the top plate of my stirrer. It does not interfere with the spinning magnets.
I independently control temperature by on time of the heater by using an old refrigeration controller with the NO contact used instead of NC side of the control relay that uses a thermocouple as its sensor. The sensor geta taped to the side of the 4l stainless vessel I use when mixing heated chems. The power side of the heater is fed by a solid state relay.
I have also used left over refective bubble wrap around the sides of the vessel, and a piece of rigid foam insulation over the top to keep heat in if it is a long stir.
It is not pretty, but the price is right, since everything in this set up apart from the stirrer came used over time for either as thrift or garage sale purchases.
my real name, imagine that.
Mike, you truly are MacGyver.
Let me ask you something. If the rule you followed brought you to this, of what use was the rule?
- Anton Chigurh
The one I have came from the lab in a closed-down county hospital. New it would be $500, surplus it was part of a large box of laboratory junque that I bought for $5. Someone got in ahead of me and bought all the analytical balances. I should have bought the waterbaths - they regulate to 37C/98.6F.
I would search ebay and be on the lookout for closings at hospitals, clinics and laboratories. I just looked at ebay - lots of fairy-tale pricing going on. If you look at completed items you can see many sold for $30 - $80.
I am thinking of putting together and selling a combination PID temperature controller and stirring paddle that could be used with any electric skillet, slow cooker or othersuch appliance for either waterbath or mixing operations.
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Jeff, I bought a little Hanna HI 190 M magnetic stirrer online, from an Amazon reseller I believe. I see they are selling for around $75 right now. It is not heated but that has not been an issue for me. I just heat the water up in my darkroom microwave before mixing in chemicals. Now that I have begun mixing as many of my solutions as practical, you would have to bring a very large stick to take it away from me.
Thanks for the recommendations all. Maybe I don't need a heater after all?
Hmm ... I suppose I could make one with an old car engine and some duct tape ....
I don't remember where it was that I saw it, (might have been here) but if you really want to do the combination heating/stirring thing, go steampunk and adapt a steam-powered record turntable - the piston on the steam engine can run the stirrer and the steam/exhaust from the boiler can be vented into a tube that encircles your vessel.
Now that would be awesome!
Originally Posted by TheFlyingCamera
I purchased the Corning PC-420 stirrer/hot plate. At first I wasn't going to go for a Hot Plate model and I'm glad I did. Most chemicals want to be stirred in warm/hot water. Since I use bottled distilled water it would be just one more step in heating it or microwaving it.
They can get expensive for a good lab rated model but they're worth it. As already mentioned you add water, chemicals a bit at a time and walk away. And to think, I used to slave over stirring and stirring and stirring the mix in a graduate.
You will need the magnetic stirrer bars (Mine came with one that looked like a football, I purchased new ones that look like more of an elongated pill) and I recommend a nice glass Pyrex beaker. I have one that is 800ml, I really need to get a 1L model.