DIY Magnetic Stirrer

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Backglass

Backglass

0
Jun 4, 2007
139
Putnam County, NY
I certainly don't want to rain on anyones parade as those look very slick and well designed.

That being said, stir plates are very easy to make for under $15 if you are a handy DIY'r. I am a homebrewer and we use stir plates for yeast propagation. Homebrewers are notoriously cheap and many make there own stir plates out of an old computers muffin fan, rheostat and a couple of rare earth magnets. They are designed to run on 110 volts and spin/support MUCH larger flasks (4,5,6 liters!) but you could easily scale it down and make a mini DC unit. Half the electronics homebrewers need are to convert AC to DC, which would be unnecessary for pool testing as the fans are DC anyway. The magnetic stir bars are available everywhere...even eBay.

Ideas and Inspiration:

Stirplate Wiki How-To
Tupperware Stir Plate
Cigar Box Stir Plate
Another Stirplate How-to
 
To make a DIY magnetic stirrer with an electronic speed control and in a plastic case will cost more in the realm of $35 to $40 dollars. I know because I priced them out. You can make a very basic one with just a rheostat and a PC fan motor and a power supply for about $15 if you put it in something like a margarine tub or something like that. Not everyone is a DIYer and for those that arent' the Apollo Pools unit IS an excellent value!!
 
I did make an AC version with a old pc fan but it just wasn't very convenient. When I looked into making a decent DC version it was going to run around $37. Went on ebay just to see what was available and most DC powered stirrers were over $75 used and not in very good condition. Then I came across this one without the beaker and rod (I use the taylor comparator tube and a small magnetic rod from my son's magnetix set :lol: )for $35. Shipped the total was $42. Worth every penny!!!
 
Another option is Ebay.

Magnetic stirrers are all fairly much the same, and there is a wide selection on Ebay for fairly cheap.

The DC battery powered bit offered by the original post is a nice feature though if you need it, but most people lately seem to be testing at their kitchen tables not by the pool.
 
Backglass said:
nikonsal said:
Then I came across this one without the beaker and rod (I use the taylor comparator tube and a small magnetic rod from my son's magnetix set :lol: )for $35. Shipped the total was $42. Worth every penny!!!
Click to expand...

What one is $35? The OP's link shows $79 dollars. ($65 +14 shipping.)
Click to expand...

The unit that I purchased for $35 on ebay is the older style unit that Paul use to make and did not come with beaker and stir bar. The new version is somewhat smaller.
 
Split off of Portable Magnetic Stirrer from Apollo Pools. Jason Lion

nikonsal said:
I did make an AC version with a old pc fan but it just wasn't very convenient. When I looked into making a decent DC version it was going to run around $37. Went on ebay just to see what was available and most DC powered stirrers were over $75 used and not in very good condition. Then I came across this one without the beaker and rod (I use the taylor comparator tube and a small magnetic rod from my son's magnetix set :lol: )for $35. Shipped the total was $42. Worth every penny!!!
Click to expand...

What did you use for a magnet? I made one that works flawlessly from a PC fan and used the rare earth magnet from an old hard drive just as internet plans indicate and with a 12v power source work for all 25ml volumes without any need to adjust speed and I use a 9v power source for the 10 ml volumes again not needing any speed adjustment. my local Leslies gave me the stirrer bar (yes gave as in free) so I had no cost in putting mine together.
 
Re: Portable Magnetic Stirrer from Apollo Pools

I made one yesterday from some spare parts that were laying around. Works great! I used a brad as a stir stick, a CD cover for a tray, on old 12V power supply and the magnet is from an old hard drive. Cost $0.00
 

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Re: Portable Magnetic Stirrer from Apollo Pools

Well done meatloaf - good idea on the CD case. I used a small piece of acrylic for mine. How did you attach your magnet and what about balance. I used velcro so I could reposition the magnet to get a good balance. Glad you posted a picture in operation so those can see the results.
 
Re: Portable Magnetic Stirrer from Apollo Pools

meatloaf said:
I used a brad as a stir stick
Click to expand...
invest the $3 and get a non-reactive teflon coated stirbar. Using brad can cause interference with some of the tests since it is possible that some of the reagents could react with the metal (and we are dealing with redox reactions in the FAS-DPD test and the CH test can suffer interference from metals).
 

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Since I am a gadget person...this do it yourself stirrer thread caught my attention. My wife is a computer guru person...and upon request delivered to me "the required" dead hard drive and a fan. After removing the magnet from the drive I started positioning it on the fan hub. I attached it with a small piece of scotch tape. After 5 slight adjustments we hit the sweet spot and almost no vibration. I secured the magnet with several drops of superglue (hobby grade). I used an old CD for the cover. For the stirrer bar I used a small brad cut to 3/8". I used some sewing thread and wrapped it around the center of the brad to create a ridge in the middle. That was secured with a little superglue and activator. Next I covered the brad (with the thread in the middle) in food grade silicone and then slipped a piece of heat shrink over it. After shrinking and curing time...I cut it down to 1/2" total (1/16" past each end). It is smooth and sealed and the ridge in the middle is obvious.

For power I used an old power supply that used to fit.....something :scratch: 12 vdc output, 500ma...wired it and secured everything.

The testing went perfect the first time! :goodjob: The ridge on the bar worked great and is silent in operation. Actual work time on this was about 30 minutes...and another 30 for prep and clean up. Before I started this project I checked with Kathy and she assured me we could afford to purchase one already made... :lol: However, I opted for the DIY project. My thanks to everyone on the forum for the great info!

Time spent on project: 1 very gratifying hour
Total parts purchased: Zero
The Satisfaction of DIY: Priceless :cheers:
 
Crabboy,
Thanks! Nice "project box" on your stirrer :goodjob: I will probably leave mine "naked" :oops: for the sake of space. Has anyone tried to run one of the 12 vdc fans on a 9 volt battery? I think I may give that a try on another fan. That would make it more compact and portable. Thanks again...

Travis :-D
 

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