Magnetic stirs for chemistry mixing?

eli griggs · Feb 10, 2022

I use a home built stir, made in an old silverware box, after the fashion of beer makers home units.

Have you made use of one of these or more expensive units with heating elements?

Bill Burk · Feb 10, 2022

I use the cheapest water-powered stirrer there is and think it’s the way to go.

Bill Burk · Feb 10, 2022

craigclu · Feb 10, 2022

I bought a used stirrer (heated) many years ago and can't imagine functioning without it after having one. Some of the stubborn solubles simply get a run it and forget it routine.

gordrob · Feb 11, 2022

I had a Wein Magnetic unit for a long time but upgraded to a Corning Magnetic stirrer and wouldn't be without it. It is not the heated unit but it it suits what I need.

removedacct3 · Feb 11, 2022

craigclu said:
I bought a used stirrer (heated) many years ago and can't imagine functioning without it after having one. Some of the stubborn solubles simply get a run it and forget it routine.

I am with Craig ... after I bought one I felt very foolish for not buying one sooner

juan · Feb 11, 2022

A friend worked in a hospital lab that was throwing away a non-heated one. She grabbed it and gave it to me. I wouldn’t be without.

Pitotshock · Feb 11, 2022

I got a non-heated one with a darkroom collection I bought. An absolute delight to mix up chems, I get to work on the next solution, or clean up some of the other labware while it whirs away in the background.

lantau · Feb 11, 2022

I bought a used heater-stirrer on eBay. The same model made, by Ika, which I first used as a student. Later we also had the occasional more modern model from Ika and other manufacturers. But this one is my favourite and it was pretty clean.

While the Patterson stirring rods are really good for what they are, a stirrer makes things so much easier with material that dissolves somewhat slowly. And heating helps a lot with Metol and the like. I made a litre of DK60a, recently, to see if it can replace Foma Retro developer. It can't. But the stirrer held the temperature nicely and the Metol dissolved steadily.

I once tried to make Formalin solution from paraformaldehyde with just a beaker and hot water. An absolute nightmare. With the heater-stirrer it was quite easy. However, I directly made the final diluted solution. Even with the stirrer it might not be so straight forward to dissolve all the required paraformaldehyde for a full strength formalin solution.

When working in a lab we take all the little tools for granted. When I started developing at home I first chose Rodinal, because it was so easy to mix with hardly any equipment at all. After a few years, now, I have got quite some useful stuff, like a professional pH meter, pro thermometer, this heater stirrer, lab and glassware and the latest: A proper balance with mg precision.

Can you do without? Sure, many do. But it makes work a lot more pleasant. Even more pleasant would be a real lab. Working in a fume hood. Purging solutions with, and storing them under Argon, for example. I wish I would have done photography when I had access to all this in a large University lab...

Quite amazing that you build your own, btw. Even if it is a stirrer only.

Paul Howell · Feb 11, 2022

This post should be in darkroom equipment, a number of posts on mixing chemistry already there.

eli griggs · Feb 13, 2022

It's a simple thing to make, which is part of why I wonder about those that do no make their own.

Mine wants a new case and I'll probably make one, but all you really need is a phone charger, 12v computer fan, glue and super magnets, plus an on/off switch or rheostat and Plexi for a top, load bearing surface.

And, of course, a stir bar.

I have a monster timer array that includes at least six timeolites and a power control that I pull out now and again just to better control the mixer's fan rotation speed.

I first could no find a local supply for the actual stirs nearby, so I made my own with prep added glass syringes in auto-injectors, which I removed the needle from, used a small standing torch to close that end with wooden sticks, inserted a 'thick' section of cut nail and then closed the back opening.

With a small 'O' ring glued in place, in the outside, middle of the tube, by a dot of hot glue, it worked fine, but Amazon &eBay sells them and the hard plastic shell spins better, so I use these now

lantau said:
I bought a used heater-stirrer on eBay. The same model made, by Ika, which I first used as a student. Later we also had the occasional more modern model from Ika and other manufacturers. But this one is my favourite and it was pretty clean.

While the Patterson stirring rods are really good for what they are, a stirrer makes things so much easier with material that dissolves somewhat slowly. And heating helps a lot with Metol and the like. I made a litre of DK60a, recently, to see if it can replace Foma Retro developer. It can't. But the stirrer held the temperature nicely and the Metol dissolved steadily.

I once tried to make Formalin solution from paraformaldehyde with just a beaker and hot water. An absolute nightmare. With the heater-stirrer it was quite easy. However, I directly made the final diluted solution. Even with the stirrer it might not be so straight forward to dissolve all the required paraformaldehyde for a full strength formalin solution.

When working in a lab we take all the little tools for granted. When I started developing at home I first chose Rodinal, because it was so easy to mix with hardly any equipment at all. After a few years, now, I have got quite some useful stuff, like a professional pH meter, pro thermometer, this heater stirrer, lab and glassware and the latest: A proper balance with mg precision.

Can you do without? Sure, many do. But it makes work a lot more pleasant. Even more pleasant would be a real lab. Working in a fume hood. Purging solutions with, and storing them under Argon, for example. I wish I would have done photography when I had access to all this in a large University lab...

Quite amazing that you build your own, btw. Even if it is a stirrer only.

lantau · Feb 14, 2022

I like the idea of a glass encased stirrer bar! Is the stirrer heavy enough to support a 1L (Patterson) measuring jug? I'm stirring the developer while chilling it to 19°C with a frozen gel pack. And the 5L (Vitlab) measuring jug when dissolving Xtol and the like.

eli griggs · Feb 14, 2022

I use one gallon jars or Anchor plexiglass four quart measuring cups, but doing so means you need to up the number/power of super magnets attached to the fan blades

The Plexi stirrer top plate is quite strong, and in the one I hacked together uses duck tape to hold it in place and keep spills out of the electrics.

Glass stir bars are easy to make, just spend a few minutes watching how glass blowers handle hot glass with simple tools.

Good Luck.

mrosenlof · Feb 15, 2022

I have a heated stirer use it for glycol concentrates. Works great. Very old and cheap.

Alan9940 · Feb 15, 2022

I used a non-heated magnetic stirrer for years and it works fine, but when I recently started mixing 510-Pyro, again, I found that a heated stirrer was more efficient and did a better job overall.

MattKing · Feb 16, 2022

I'm moving this to the Darkroom Equipment forum.

Neal · Feb 17, 2022

You can find all the stirring bars you want on ebay.

eli griggs · Feb 18, 2022

Yep but making a few of your own appeals to a few folks who like to see what they can do and how well they can do it.

Cheers.

Vaughn · Feb 18, 2022

Hard to beat a Corning stirrer. Mine died eventually...a burnt spot on the curcuit board. I have a cheap China-built right now. Works okay...probably a 5 on a scale of 10...motor is weak and does not instantly stop. Cornings are about 8+. Adding heat will bring it up to 9+.

koraks · Feb 26, 2022

eli griggs said:
rheostat

Hehe
No no, those belong back in the 1940s where they came from.

Magnetic stirs for chemistry mixing?

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Magnetic stirs for chemistry mixing?

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