My homebrew stirplate

I personally am happy I went with the 12v power supply. I don't think it would spin fast enough with a 6v. As it is, I can get the vortex down to the bottom on a 2000ml starter.

With a new starter, I have to start it on low, and slowly turn it up to high. It does not throw the bar unless I start it on medium to high.

I used 5 lb 7/16 magnets.

Ben25 said:

I personally am happy I went with the 12v power supply. I don't think it would spin fast enough with a 6v. As it is, I can get the vortex down to the bottom on a 2000ml starter.

With a new starter, I have to start it on low, and slowly turn it up to high. It does not throw the bar unless I start it on medium to high.

I used 5 lb 7/16 magnets.

Click to expand...

I definitely had trouble starting with 12v and the 25ohm rheostat. I wonder if maybe your magnets are stronger than mine? I don't know how I'd measure the strength, they're just out of a hard drive.

Do you happen to know what amperage your fan is? That's really the only other variable...

The fan is a .3 amp...

Ben25 said:

The fan is a .3 amp...

Click to expand...

That might just do it. That .1 amp amounts to an extra 2.5v drop, making the range 4.5v - 12v.

voltage drop = amps x ohms = 0.30 x 25 = 7.5v drop

I discovered a great source for magnets. At Petsmart you can get a magnetic aquarium cleaner. I had the smaller size for my old aquarium, so I dug it out, busted open one side, and inside were two of the strongest magnets I've ever found, stronger than the rare earth magnets I got from mcmaster. In the other piece there are two more of the same magnets. They are attached to a metal bar, perfectly spaced. Just centered it up, turned on the fan, and it worked like a charm.

Would an 80mm fan work?
Masscool
I have a bunch of these laying around. Newegg had a sale going and I bought a bunch.

Well I got this thing working using a 1/2 inch stir bar in a 1000ml bottle. The vortex in the middle wasn't very large though. I'm wondering, the bigger the stir bar the larger the vortex? Is it possible for the magnets to slow down the fan too much and not create a large vortex? Is it because I'm using a 80mm 12v fan and not a 120mm? Please, someone who knows about this stuff please help me out. I wanted to brew on Monday!!!

schweaty said:

Well I got this thing working using a 1/2 inch stir bar in a 1000ml bottle. The vortex in the middle wasn't very large though. I'm wondering, the bigger the stir bar the larger the vortex? Is it possible for the magnets to slow down the fan too much and not create a large vortex? Is it because I'm using a 80mm 12v fan and not a 120mm? Please, someone who knows about this stuff please help me out. I wanted to brew on Monday!!!

Click to expand...

It's not the stirbar size but the speed it moves at.

The vortex size doesn't mean too much, as long as you have movement it's doing its job and the yeast will grow.

How did you make your stirplate? What voltage? Any rheostat?

hexmonkey said:

It's not the stirbar size but the speed it moves at.

The vortex size doesn't mean too much, as long as you have movement it's doing its job and the yeast will grow.

How did you make your stirplate? What voltage? Any rheostat?

Click to expand...

12v DC adapter
80mm 12v DC fan
Project box
On/Off Switch
2 Magnets from harddrive

I didn't use a rheostat because I didn't need one. The stirplate starts slow enough to where the bar won't get thrown at the beginning Once it gets to full speed its not throwing the bar either. I tried using a 1 inch bar it it works much better for me than the 5/8. Tried a 2 inch but the magnet in it is too strong and won't even let the fan turn. I've only tested it in water and it gets going pretty good. Is there another substance that might have the consistency that wort does?

If you're not too handy soldering or just don't feel like messing with electronic components, you can use a Zalman Fan Mate 1 or Fan Mate 2 instead of the LM317 circuit, since it's pretty much the same thing.

I bought mine at CompUSA years ago for something like $10, I think the Fan Mate 2 is around $4 at newegg.

I use it with a 6V 500ma wall-wart and a 120mm 12V .35a fan that has a large hub, and it'll spin 5L with a 1" stirbar. Just make sure your magnet's magnetic axis is well-centered along the fan's rotational axis and it won't throw the stirbar. And if your fan has a hard time starting at lower voltages, you have to space the magnet away from the fan hub. I'm using an exceptionally powerful magnet pulled from a 15k rpm server drive, and the fan won't spin up at lower power with the magnet right against the fan hub.

OBTW - testing with a digital multimeter, I saw 4.7v low to 7.6V high output with the Fan Mate, and 9V without it on the 6V rated wall-wart. You might could rig a 3-way switch - off, thru Fan Mate, and bypass for faster speeds.

You could use an 80mm, but make sure the fan motor hub is appropriately sized for the magnet you use, and be aware that 80mm fans usually spin at MUCH higher rpms than 120mm fans.
-keith

edit - oops, sorry about resurrecting a zombie thread. I found it through another thread link earlier today...

http://img33.picoodle.com/img/img33/3/11/16/f_starter2m_0f0f1ad.jpg



Materials:

Old Plastic VHS case
Old Phone Charger
Rheostat from Radio Shack
Switch from Radio Shack
Control Knob from Radio shack
Old PC Fan and magnet salvaged

done for 8 bucks

I'm interested in a stir plate if you have any more. You can email me at [email protected]

So I recently cleaned out the garage and one of the things I threw out were really old hard drives and I am kicking myself now.

So if I had to get some Neodymium Magnets at a local store, where should I go?

I just did my first starter with His stir plate. it worked like a charm. I bought expired yeast from my LBS for 2 bucks. I got Wyeast London ESB (I don't remember the number) It was a lager yeast. I used a 2 liter flask, I bought the starter kit from Morebeer for 15 bucks and used a 2" stirbar. It took 48 hours for the expired yeast to catch on but once it did the flask looked like it was filled with milk. I cold crashed it and had a huge starter on my hands. I will brew the beer tomorrow night. I can't wait to pitch the starter on it. The starter can sit in the fridge for 5 days no problem in the fridge once its done. Just make sure you cap it off with plastic wrap and a rubber band. BTW You can buy magnets online for 8 bucks. I got the 12lb pull magnets. they work great.

Sumo said:

I just did my first starter with His stir plate. it worked like a charm. I bought expired yeast from my LBS for 2 bucks. I got Wyeast London ESB (I don't remember the number) It was a lager yeast. I used a 2 liter flask, I bought the starter kit from Morebeer for 15 bucks and used a 2" stirbar. It took 48 hours for the expired yeast to catch on but once it did the flask looked like it was filled with milk. I cold crashed it and had a huge starter on my hands. I will brew the beer tomorrow night. I can't wait to pitch the starter on it. The starter can sit in the fridge for 5 days no problem in the fridge once its done. Just make sure you cap it off with plastic wrap and a rubber band. BTW You can buy magnets online for 8 bucks. I got the 12lb pull magnets. they work great.

Click to expand...

I have everything but the earth magnets. Where did you get those?

I think I may need to use a bigger fan, mine is only a 80mm

I ordered them from here:

MAGCRAFT® Neodymium Magnets

Product ID: NSN0641
ProductName: Rare Earth Magnet - Disc - D0.500 x T0.250 - Package of 8
Description: Rare-Earth Neodymium-Iron-Boron (NdFeB) Disc Magnet Size - Diameter 0.500" (12.70mm) x Thickness 0.250" (6.35mm); Grade N40; Pull Force - 10.69lb/4849g

These had a really strong pull and they are round and small. The case I used was too big and I had too much head space between the fan and the top of the case so I double stacked the magnets and used 4 total. As for the small fan, that is the beauty of using that large metal washer.. Gives you a little more space to move the magnet around. Trust me it works well. Let me see if I can figure out how to post the pics I took.
I hope this helps you out. Buying the magnets was easier for me. Dealing with HD's can be a *****. I am lazy and would rather spend 16 bucks and not have to deal with taking them apart.

edited message-no longer valid

Sumo said:

I just did my first starter with His stir plate. it worked like a charm. I bought expired yeast from my LBS for 2 bucks. I got Wyeast London ESB (I don't remember the number) It was a lager yeast. I used a 2 liter flask, I bought the starter kit from Morebeer for 15 bucks and used a 2" stirbar. It took 48 hours for the expired yeast to catch on but once it did the flask looked like it was filled with milk. I cold crashed it and had a huge starter on my hands. I will brew the beer tomorrow night. I can't wait to pitch the starter on it. The starter can sit in the fridge for 5 days no problem in the fridge once its done. Just make sure you cap it off with plastic wrap and a rubber band. BTW You can buy magnets online for 8 bucks. I got the 12lb pull magnets. they work great.

Click to expand...

I just wanted to say that I am a huge fan of starters now. The starter I made took off in 3 hours and more importantly I feel I had better results with a starter then not using one.

Just wanted to say thanks to everyone who contributed to this thread. Finished my own stirplate last night. It was CHEAP and pulls a strong vortex right down to the bottom.
Materials:
--Radio shack project box
--Illuminated toggle (had this)
--Radio shack potentiometer and knob
--12 v case fan from dead computer
--Pair neobdenum magnets 10mm from ebay, dirt cheap
--1000ml Ehrlenmeyer flask from LHBS, $15
--1" stirbar off ebay, cheap
--Variable voltage 3-12V wall wart free from the computer technician's junk closet here at work

This will pay for itself with the first three packs of yeast. I will just culture the three that I use most often, keep them in the fridge in baby food jars, and keep right on re-using. Most importantly, I can pitch a big starter every time.

And also it is just cool to watch. I never even knew these things existed until I read about them here.

Thanks everyone.

The last stirplate I made used Wonderflonium Magnets coupled to an Inverse Reactive Intensifier. My idea was to control vortex creation with a reactive feedback circuit sensing motion/flow. Unfortunately the Scotch Tape I had used to hold the feedback circuit onto the flask gave way and the IRI ran loose. Before I could unplug it, it had created an antimatter field proportional to the mass of the Wonderflonium, squared.

I'm grateful that nobody was hurt, but that was the last of my Wonderflonium, and now I can't build that Freeze Ray I had my heart set on!

I'd offer to share some of my wonderflonium, but I used the last module in my .

Okay, so I know this thread has been killed and resurrected several times, so I'm sorry. But I can't shake the feeling that I've just scrapped a perfectly good 1 Gig HDD from my first computer and am not using it to it's full potential.

I have in my hands a 12v brushless motor and perfectly smooth palette to place the magnets on that would seem to be perfect for the plate... but does anyone know how to wire a system that could use a potentiometer on a HDD spindle drive? I have no idea when it comes to electronics, but would love to see this thing back in motion.

From Wolfenstein 3D to a perfect yeast pitch!

Just ripped a 12V DC fan out of an old computer, and wired it up to a 12V speaker wall jack. When I set a rare earth magnet from a HD on the back it holds itself on. When I turn the fan upside down the speed decreases quite a bit, is this normal for computer fans?

DonLiguori said:

but does anyone know how to wire a system that could use a potentiometer on a HDD spindle drive? I have no idea when it comes to electronics, but would love to see this thing back in motion.

Click to expand...

I believe a spindle drive from a hard drive is what's known as a "stepper" motor. Those are made for precision movements (even if that movement is spinning fast -> spinning faster), and so require an actual controller giving signals to it. Way more electronically complex than a 10k pot, and therefore probably not worth the trouble.

jim_reaper1066 said:

Just ripped a 12V DC fan out of an old computer, and wired it up to a 12V speaker wall jack. When I set a rare earth magnet from a HD on the back it holds itself on. When I turn the fan upside down the speed decreases quite a bit, is this normal for computer fans?

Click to expand...

I've never seen that happen but it might be the way the blades are connected to the motor. The weight of the magnet may be pulling the spindle out of alignment and causing friction.

i bought all the parts to make this stir plate. My concern is i got a 3mm blue LED with a voltage rating of 3.5-4V. What would be the best way to hook this up without burning it out?

ekjohns said:

i bought all the parts to make this stir plate. My concern is i got a 3mm blue LED with a voltage rating of 3.5-4V. What would be the best way to hook this up without burning it out?

Click to expand...

Depending on your power supply, just add a resistor inline with the led to drop the voltage to your 3.5-4V.

boogyman said:

Depending on your power supply, just add a resistor inline with the led to drop the voltage to your 3.5-4V.

Click to expand...

Make sure the resistor wattage matches the wattage of the motor to handle the heat created by the voltage it's holding back so it doesn't burn up. A wire wound hollow center tap resistor with slider, Ohmite a brand name example will work great plus adjustable resistance. larger wattage than the motor load will not hurt.

BrewBeemer said:

Make sure the resistor wattage matches the wattage of the motor to handle the heat created by the voltage it's holding back so it doesn't burn up. A wire wound hollow center tap resistor with slider, Ohmite a brand name example will work great plus adjustable resistance. larger wattage than the motor load will not hurt.

Click to expand...

I certainly wouldn't run the fan/motor off the same resistor as the LED.

ekjohns, you need to calculate what resistance you need by knowing the current (mA), the forward voltage (vf) of the LED, and the voltage of your power supply. You would hook all of that up in parallel to your fan controller.

http://www.quickar.com/noqbestledcalc.htm

It will be either a 12VDC 500mA or 12VDC 1A power supply. I can get either for the same price. So would a 470 ohm 1/2W resistor work hooked straight from the power supply? Do you recommend one power supply over the other?

Scrimmia - thanks that is exactly what i needed, any thoughts on the Amp raiting of the power supply?

For knowledge sake what is the raw equation to calculate the resistance needed. Just want to prove to myself i can do the actual math i use to do in high school

Assuming the LED is wanting 20 ma (typical max), yeah, the 470 1/2W should work fine. Really, a 1/4W should do the trick.

The power draw of the LED/resistor combo is going to be virtually negligible in this case, so size the power supply based on the fan, figuring in some overhead for the control circuit.

Edit: the calculation is just Ohm's law. V=IR. We need the resistance, so R= V/I. The LED is going to drop 4 volts, so the resistor needs to drop 8. R=8/.020=400 ohm.

As stated above "go larger for control current demands", by this I would use the larger power supply should you add other future loads your golden.

I have a 9v power supply that i would like to use. This would be with the LM317T controller and a 80mm 12V fan. many people talk about the stir plate throwing bars at top speeds. Would a 9V power supply still give me a wicked vortex or is a 12V necessary?

ekjohns said:

I have a 9v power supply that i would like to use. This would be with the LM317T controller and a 80mm 12V fan. many people talk about the stir plate throwing bars at top speeds. Would a 9V power supply still give me a wicked vortex or is a 12V necessary?

Click to expand...

The answer to that question (as most things in life) is -- it depends.

Not all 80mm 12V fans have the same top RPM, some are slower at full speed than others.

for example this fan has a speed of 2500 RPM while this one tops out at 1700 RPM. Both are 12v 80mm computer case fans.

Mine will pull a vortex to the bottom of a 1L flask at 9v, but I generally run at 4.5v because you don't need to pull a "wicked vortex" all you really need is to keep the starter moving.

Yeah that was my thought that most fans to get a nice vortex will only be running at 9V max so the extra 3 volts is just a bonus. it would be cool to find a 11V power supply so i could say "but this goes to 11"

ekjohns said:

Yeah that was my thought that most fans to get a nice vortex will only be running at 9V max so the extra 3 volts is just a bonus. it would be cool to find a 11V power supply so i could say "but this goes to 11"

Click to expand...

oblig: http://xkcd.com/670/

Just ordered the following from Jameco:
Part # Description
15270 @ CAP,CERM,DISC,.1uF,50V,20%
23579 IC,LM317T,TO-220,
29082 POT,LINEAR TAPER,1/2W,10K OHM
162481 KNOB,1/4"SHAFT,METAL,RND,SLVR,
330772 @ CAP,RADIAL,1uF,50V,
577221 SWITCH,ROCKER,RRA22H3BBBNN,
609545 @CAP,RADIAL,0.1uF,50V,
637183 LED,PANEL MOUNT,GREEN,T13/4,
690865 @ RES,CF,1K OHM,1/4 WATT,5%,
696722 HEAT SINK,TO-220,1 HOLE,2 PINS

Going to Radio Shack for the enclosure, the power supply jack, and board.

I just harvested 6 magnets from some hard drives on the way to be destroyed at work and it got me thinking when I was stripping these down to the bare chassis - is anyone using the motor from the drive that spins the platter?

Finished everything but a bit of glue and positioning the magnets tonight. I'm hoping to be finished tomorrow. I wired the LED to the board and jumped to the leads to the fan so I'll know if the circuit is intact rather than just knowing if I'm getting power. I have a 12V and 9.4V power source thar both have M-sized jacks.

I used a set of instructions online for the circuit, but rather than just pile up the solder when putting the wire leads in, I ran them through the board and jumped with solder rather than wiring the underside of the board.