My shamelessly cheap $12 DIY stir plate

[Nablis]

http://www.newegg.com/Product/Product.aspx?Item=N82E16811999130

newegg has same fan 14.99 free shipping. Awesome idea op. This is cheap enough and easy enough for me.

 

[CS223]

I can't get my stir stick to stick to the magnets on the fan... Are they just not strong enough magnets ya think? I have tried two different sets...one I got to stay for around 2 minutes or so but slowly but surely it comes off and I can't turn it up full blast without it coming off. Stronger magnets? I have a washer between the magnets like the OP says also...

Do you have the poles configured correctly? You need one stack of magnets with the N pole up and the other with the S pole up.

If you have your magnets stacked like this all stuck to one another: <<<<<<
pull the stack apart in the middle and stick them to the washer like so: \/ /\

 

[SoupNazi]

Rigged one of these up on Friday and it works great on the lowest speed but tends to throw a 1.5" bar in a 2L flask.

No biggie- it still does its purpose just fine for under $20!


Thanks OP!

 

[tre9er]

To everyone having issues with throwing the bar:

Try putting dip-tube o-rings on both sides of the bar, then try again. It worked for me, interested to know if it helps anyone else.

 

[mdfairbairn]

To everyone having issues with throwing the bar:

Try putting dip-tube o-rings on both sides of the bar, then try again. It worked for me, interested to know if it helps anyone else.

Interesting ... Will be trying that this week end when I get home!

 

[RoadKing]

Try putting dip-tube o-rings on both sides of the bar, then try again. It worked for me, interested to know if it helps anyone else.

I use two O rings too. My stir bar has a raised ridge in the center and it
immediately threw it. I put an O ring on either side and haven't had a problem since.

 

[seatbelt123]

I had the same problem fit fixed it by shaving off the raised portion of the bar.

 

[Metzger22]

tagged. This build is on my to-do list.

 

[nghtmre4u]

Thanks for the info

 

[tre9er]

Interesting ... Will be trying that this week end when I get home!

Did it work?

 

[mdfairbairn]

Did it work?

Get home tomorrow ...

 

[rajun50]

Just an FYI: I noticed that if you disconnect the speed control unit from the fan, it will run slower. That may be helpful for smaller starters.

 

[ObiDon]

After reading this thread last week, I immediately went to Amazon and purchased the Thermaltake usb fan unit and I couldn't be happier.

I completely removed the fan shroud and the speed control knob. The fan was attached to the base of the box using double sided sticky tape. I used the box that my RAZR Maxx came in for the case. I punched a hole in the box for the speed control knob to stick through and just used a bit of crazy glue on the back side to hold everything in place. I punched another hole out the back for the power cable.

The washer the hard drive magnet is attached to is held to the fan by double sided sticky tape. I used it with a 1" stir bar to whip up my last 1L batch of starter and it worked great!


Even on low, this DYI stir plate has no problem creating a vortex.

Thanks for the tip!


Don

 

[tre9er]

Get home tomorrow ...

OK, did it work

 

[apshaffer]

My stir bar is rolling rather than spinning. I'm using one magnet from a hard drive and a 2" stir bar that I grabbed from the lab at work. Think the stir bar is too big? It does have a rib in the middle. It rolls around then throws the bar. Any thoughts? I'll see if they have a smaller bar tomorrow.

 

[ObiDon]

...It rolls around then throws the bar. Any thoughts?...

Have you tried adjusting the distance between the magnet and the stir bar? I had to muck about with mine for a bit before I got it just right.

Don

 

[tre9er]

Have you tried adjusting the distance between the magnet and the stir bar? I had to muck about with mine for a bit before I got it just right.

Don

Yeah, try adjusting the distance with shims under the flask first, to increase it, and run the fan on the slowest speed. If more distance isn't the answer, perhaps it's less.

 

[barrooze]

My stir bar is rolling rather than spinning. I'm using one magnet from a hard drive and a 2" stir bar that I grabbed from the lab at work. Think the stir bar is too big? It does have a rib in the middle. It rolls around then throws the bar. Any thoughts? I'll see if they have a smaller bar tomorrow.

If you have another HD magnet, try putting it on top of the one you already have on the fan. This worked wonders for me. I don't know if it was the increased magnetic field or the reduction in distance between the bar and the magnet, or both. Either way, I don't through my bar anymore.

 

[ObiDon]

...It rolls around then throws the bar. Any thoughts?...

The other thing I did was to slip two O-rings onto the stir bar. I'm not sure if that played any part in getting it to spin properly. It sure is quiet now though.

Don

 

[apshaffer]

I figured it out. I wasn't letting the magnet and the stir bar align before turning on the fan. I also grabbed a smaller stir bar which works much better.

 

[ObiDon]

I figured it out...

Yay!

 

[atimmerman88]

I took your idea and made one similar using scrap materials from work.

Ready to step up my brewing game with starters now

 

[troyh]

I took your idea and made one similar using scrap materials from work.

Ready to step up my brewing game with starters now

My stir plate uses lucite too and looks very similar. I love it.

How'd you cut that big a hole in the center? Hole saw? I worry that I'd crack the lucite with a big hole saw. It seems like a good idea to get the magnet closer to the stir bar. Let us know how well it works.

 

[atimmerman88]

My stir plate uses lucite too and looks very similar. I love it.

How'd you cut that big a hole in the center? Hole saw? I worry that I'd crack the lucite with a big hole saw. It seems like a good idea to get the magnet closer to the stir bar. Let us know how well it works.

I used a 2 3/4" hole saw. It's 3/8" lexan. This supplier claims stuff is more shatter resistant than other poly sheets. I've cut it with a band saw and jig saw before with no issues. It's pretty handy stuff!

Looking forward to making a small starter tomorrow!

 

[bfinleyui]

Tagged for future reference. Might have an old power supply I can gut for both the fan and enclosure. Itching to start using liquid yeasts over the same old same old dry yeast.

 

[SoupNazi]

Successfully used this stir plate this weekend on a 1.5 L starter of 3711.
worked great on the lowest setting.


Thanks again!

 

[Matteo57]

Finally got mine to work. Weird, I have to have the flask off to the side and not centered. If it's centered it won't work. Wondering if the bottom of the flask isn't as flat as the other areas of it or something. Strange. Aw well it works so I'm happy!

 

[jkendal]

I've never known 'shameless' to be associated in any way with 'cheap'. Well, there are hookers, I guess...

 

[tre9er]

Having a weird issue with mine. When I use my 2.36L pickle jar, I have to run it on low or it will throw the bar (up to maybe half speed). I also have to use dip-tube o-rings on either side of the stir-bar (1.5" with fulcrum).

None of that bothers me whatsoever. But...when I put my 1L flask to work on this...first it wouldn't start until I turned it up to high...then it would just quit, maybe overheating? Then I had to run it on high to keep the rattling at bay, and it worked better that way.

My theory is that the flask bottom is thinner and not convex, thus it's closer to the magnet and the force is too great to start the fan, and also taxes the motor. Running it on high gives it more momentum (like riding a bike with multiple gears, you want the gears in high). Maybe I should remove a layer of magnets (i use 3 neodymium on either side of the washer) for the 1L flask...?

 

[troyh]

I've found that more magnets is always better -- you want a strong connection. But my 2" stir bar in a 2L starter is too hard for the fan to turn. A 1" stir bar in the same starter works fine.

Your fan sounds like the problem more than the flask. Some PC fans are super cheap, I've found that I need a higher-quality name brand one, the cheapies in low-end PCs couldn't turn the bar reliably.