# Homemade Magnetic Stirrer Build Project



## NoobVinter (Apr 8, 2015)

Hi everyone. I need a magnetic stirrer but I don't want to pay for it. I did some homework and here's where I am with the project.



120 mm, 950 rpm, 12V, 0.2 amp $4.99


12V, AC to DC Adapter $5.99


Switch $1.69


Non Glare Plastic Coat $4.98


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## NoobVinter (Apr 8, 2015)

And this. 

I will construct the housing and assemble soon


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## havlikn (Apr 8, 2015)

I made one last month. It works excellent. I have 90$ into everything including burette, clamps, stand, all parts


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## NoobVinter (Apr 8, 2015)

havlikn said:


> I made one last month. It works excellent. I have 90$ into everything including burette, clamps, stand, all parts




Awesome! Would it be too much to ask for pictures, and a parts list? I would like to see your design.

I knew I should have asked the experts on here first. I placed an add to buy one, nobody responded so I YouTubed it and got to where I am now. These things retail are ridiculously priced. I couldn't justify the expense, especially when I'm only planning to use a couple times a year.


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## NorCal (Apr 8, 2015)

I love it, are you going to able to vary the speed?


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## havlikn (Apr 9, 2015)

Here is the link to the one I made

http://2junky.com/video/3963249/fos-15-stir-plate-build-how-to-make-a-solderless-stir-plate.html


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## DoctorCAD (Apr 9, 2015)

The Taylor SpeedStir is $26.


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## olusteebus (Apr 9, 2015)

How important is a magnetic stirrer?


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## botigol (Apr 9, 2015)

The Taylor Speedstir seems to be for much smaller quantities.

I wasn't aware of winemakers using stir plates. I only use mine for making yeast starters for beer. 

I built mine for about $18, as I recall. Sorry, no pics. I mounted a Thermaltake 'external' computer fan into the bottom of an old Tupperware-style container. I cut a hole into the bottom of the container and hot glued a couple of magnets onto the fan. I pull a nice vortex on the 3/4 gallon jug that I use as the starter vessel. The speed is, at least somewhat, variable in that the difference in speed is strongly dependent on the volume.


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## botigol (Apr 9, 2015)

Here's a link for the fan:

http://www.amazon.com/Thermaltake-Mobile-Fan-External-Cooling/dp/B00080G0BK


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## botigol (Apr 9, 2015)

Pic of my build


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## DoctorCAD (Apr 9, 2015)

The speedstir works great for tritation during TA testing. I also use it for checking my pool water chemistry.


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## NoobVinter (Apr 9, 2015)

NorCal said:


> I love it, are you going to able to vary the speed?




Well thanks to another post, I might as well use the case fan speed control. Why not!


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## NoobVinter (Apr 9, 2015)

botigol said:


> Pic of my build




Nice! Looks like a Roomba, you know that robot that automatically cleans the floor? Hey, as long as it works right. I'd take it, heck I would buy one from you to save some time. Lol


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## NoobVinter (Apr 9, 2015)

DoctorCAD said:


> The speedstir works great for tritation during TA testing. I also use it for checking my pool water chemistry.




Yeah, that's what I was going to use it for, acid testing. I looked on line for the whole kit and kabootle and it was like $180 from Midwest Supplies. Man, my wife would straight up flip out if I did that. Lol


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## NoobVinter (Apr 9, 2015)

botigol said:


> The Taylor Speedstir seems to be for much smaller quantities.
> 
> 
> 
> ...




Genius! That's all I can say, so effective and efficient. KISS method. Keeping it simple. I'm telling you all right now I really have to start asking questions before making decisions, I could have followed someone earlier. Man....lessons learned.


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## botigol (Apr 10, 2015)

NoobVinter said:


> Nice! Looks like a Roomba, you know that robot that automatically cleans the floor? Hey, as long as it works right. I'd take it, heck I would buy one from you to save some time. Lol



I hadn't thought about it, but you're right, it does look like that! Yeah, cheap and functional is the name of my game...but somehow I've managed to spend a good amount of money on this hobby. Oh, well!


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## NoobVinter (Apr 13, 2015)

It works! Should do the trick!


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## sampvt (Apr 13, 2015)

Why is a stirrer useful in wine making. I stated on here that I agitated all my brews every day for the first 3 days of the kits startup and I got slated and advised not to agitate yeasting wine.


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## ibglowin (Apr 13, 2015)

Its used in testing TA, Sulfite levels, pH. A mag stirrer will mix the addition of your titrant well.


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## NoobVinter (Apr 13, 2015)

sampvt said:


> Why is a stirrer useful in wine making. I stated on here that I agitated all my brews every day for the first 3 days of the kits startup and I got slated and advised not to agitate yeasting wine.




Hi Sampvt,

I made this primarily to test Tartaric Acid levels using a titration kit and a PH meter. I don't know how to test sulfites yet. I can figure these two things out very easily with light colored wines, however it's very difficult to see color changes in dark wine samples. I forgot to buy the buffer solutions for my PH meter so I don't even know what's up with my Welch's Wine. Lol I keep drinking it though. All I can say right now is that it's still sweet for some odd reason, and it needs more tannin. Have a great night! Cheers


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## olusteebus (May 4, 2015)

I have a fan, a 110 volt/12 volt converter, a potentiometer and I will be getting my magnets. My potentiometer has three prongs. One is for grounding. I am making this with a tupperware bowl. I am hoping I do not need to ground this. 

how should I wire this stuff?

and what magnets do I need


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## sour_grapes (May 4, 2015)

olusteebus said:


> I have a fan, a 110 volt/12 volt converter, a potentiometer and I will be getting my magnets. My potentiometer has three prongs. One is for grounding. I am making this with a tupperware bowl. I am hoping I do not need to ground this.
> 
> how should I wire this stuff?
> 
> and what magnets do I need



Actually, I doubt that one of your potentiometer's prongs is "for grounding." For the overwhelming majority of pots (potentiometers), the resistance between the outermost two prongs is fixed. The resistance between the first and the second prongs will vary as you turn the knob. Likewise, the resistance between the second and the third prongs will vary as you turn the knob.

So you wire it like this: Take the two leads from your converter. Paying attention to the polarity, attach one directly to your fan. Attach the other lead from your converter to one of the outermost prongs of your pot. Finally, attach a wire from the center prong of your pot to the remaining terminal on your fan.

You can get small rare-earth magnets (neodymium, say) from ebay.


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## richmke (May 5, 2015)

olusteebus said:


> and what magnets do I need



http://labelpeelers.com/equipment/tools/stir-bar-for-magnetic-plate-stir-5-bag/


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## ibglowin (May 5, 2015)

Somebody correct me if I am wrong here but don't you need two sets of magnets. A stir bar magnet (obviously) for the sample beaker but then you also glue some small magnets to the fan blades themselves.


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## richmke (May 5, 2015)

ibglowin said:


> but then you also glue some small magnets to the fan blades themselves.



I believe the idea is the fan is a magnetic motor. Get it close enough to the beaker, and it should have enough attraction to move the magnet in the beaker.


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## ibglowin (May 5, 2015)

See this article:

http://www.instructables.com/id/How-to-Make-a-Cheap-Portable-Magnetic-Stirrer/


You also have to glue magnets to the fan.


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## sour_grapes (May 5, 2015)

ibglowin said:


> You also have to glue magnets to the fan.



That is certainly what I had in mind when I suggested buying rare-earth magnets from ebay! But I did not know a source for the stir-bar like Rich posted.


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## richmke (May 5, 2015)

sour_grapes said:


> That is certainly what I had in mind when I suggested buying rare-earth magnets from ebay!



Home Depot has them on-line. I don't know if they are available in the store. Might want to check Lowes, Ace Hardware, True Value, etc.


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## olusteebus (May 6, 2015)

I picked up a fan and potentiometer from Radio Shack at half price. They were closing soon. about 10 for both.


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## sour_grapes (May 6, 2015)

olusteebus said:


> I picked up a fan and potentiometer from Radio Shack at half price. They were closing soon. about 10 for both.



I should have posted this earlier, but you want a potentiometer with a low total resistance. Radio Shack has a 25-ohm, 3 Watt pot that I think would work well: http://www.radioshack.com/25-ohm-3-watt-rheostat/2710265.html


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## ibglowin (May 6, 2015)

I have a perfectly good mag stirrer but you guys are making me want to build one just to satisfy the MacGyver in me!


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## olusteebus (May 6, 2015)

sour_grapes said:


> I should have posted this earlier, but you want a potentiometer with a low total resistance. Radio Shack has a 25-ohm, 3 Watt pot that I think would work well: http://www.radioshack.com/25-ohm-3-watt-rheostat/2710265.html



gotta check mine. Just picked one up. Maybe I can get another tomorrow. No returns so I may be willing to sell mine at a good price, say 10 bucks.


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## olusteebus (May 6, 2015)

I have a 100k ohm pot

http://www.radioshack.com/100k-ohm-...html#start=14&q=potentiometer&sz=12&suggest=1

will that work?


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## sour_grapes (May 6, 2015)

olusteebus said:


> I have a 100k ohm pot
> 
> http://www.radioshack.com/100k-ohm-...html#start=14&q=potentiometer&sz=12&suggest=1
> 
> will that work?



I am afraid it will not work. Your fan would go from full speed to "off" by turning the knob approximately 0.07 degrees. Seriously.

You could make this pot work by adding a transistor to the circuit. I could draw the circuit for you if you are interested. However, I think I would just nab a pot with a much lower resistance. If you cannot find the one I posted, perhaps you can find a 100 ohm pot. That is about as high as I would go.


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## JohnT (May 13, 2015)

OK, since nobody else has done so, I guess I need to show just how stupid I am and ask.. Just what is a potentiometer? Is that much like a toy train transformer where the amount of power can be adjusted??


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## vacuumpumpman (May 13, 2015)

it will adjust the output power source

transformers will change the type of power from coming in to what's going out. your train transformer is most likely a combination of both being used.


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## richmke (May 13, 2015)

JohnT said:


> Just what is a potentiometer? Is that much like a toy train transformer where the amount of power can be adjusted??



Yes. A potentiometer is a variable resistor. As you turn it, the resistance increases/decreases. Thus, the amount of voltage it transmits changes with the resistance. The higher the voltage, the faster the fan spins. Or, in your example, the train moves.


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