bd2xu

Recipes 

I can't get my 2 inch bar to spin right with even a 12 volt but my 1 inch one spins perfect with the 12v. Best design is prob a 12v with a potentiometer to slow it down if needed. My design is a cigar box, I think the amt and type of material between the magnet and glass determines a lot. Bottom line every DIY version of a stir plate acts diff and you have to tweak and test

__________________
On Deck: Still thinking about that
Primary: Empty
Secondary: Empty
Carbing/Conditioning: Boulevard Tank 7 Clone, Sweetwater IPA Clone
On Tap: Extra Pale Ale, Coffee Oatmeal Stout
Bottled: American Wheat, Pumpkin Spice Porter, La Fin Du Monde Clone, Black IPA, Extra Pale Ale


“Beer is proof that God loves us and wants us to be happy.”
― Benjamin Franklin

fizgig

Recipes 

I might turn my 1st gen mac mini into a stir plate.

mojo2008

Recipes 

I found that most cell phone chargers have a much lower current rating that the fans we are trying to power. I started off with a 5V 200mA charger and it spun my fan, but not very fast and definitely not reliable with a starter. My current setup uses a 5V 1000 mA charger and it spins the fan fast enough that it is functional, but it still spins nowhere near as fast (even without the magnet) as it did when it was in a computer. I don't remember the current rating of the fan offhand, but between the voltage and current the charger is well below the fan's values. Ideally, if the charger's output specifications match the fan's input specifications you will get the best performance. In this case though I don't recommend running it without a pot for speed control.

Mojzis

Recipes 

A friend gave me a 120 mm 12v fan and a 12v power supply they had laying around. Re-did the whole thing and the fan if ridiculously fast now, so that's good. However I haven't got the damn bar to move. I ordered some more magnets online to see if my magnet I have isn't the right shape. I'd hate to spend the 6$ for a one inch bar instead of my 2".

mojo2008

Recipes 

Do you have a potentiometer installed? It sounds like the fan moves too fast for the magnetic fields between the magnet and the stir bar to remain coupled. I find it best to turn it on with the potentiometer set to min speed and then slowly speed it up. Eventually you will find a speed that will throw the bar.

Mojzis

Recipes 

Yeah the pot's installed, but it still goes pretty fast. However it wont throw the magnet even turned all the way up. I hope its not too fast now....

Edit: just switched the supply back to 5.6v and the bar moves a little more. Maybe the pot doesn't slow the 12v down enough? Maybe I need a bigger pot to use the bigger supply...

bd2xu

Recipes 

I found success in computer fan, washer, hard drive magnets, cigar box and 12v adapter with 1" bar. It spins perfect with a 2L flask and after centering the washer and magnets its almost silent. Perfect vortex, and I didn't have to buy one thing. I tried 6, 9, and 12 volt adapters and the 9 spun it but the 12 is better. Point is you can do this without buying a pot and doing that wiring if you have a variety of adapters laying around, just have to find the right combo.

I'm using 4 hard drive magnets from 2 old hard drives and man are they strong.

__________________
On Deck: Still thinking about that
Primary: Empty
Secondary: Empty
Carbing/Conditioning: Boulevard Tank 7 Clone, Sweetwater IPA Clone
On Tap: Extra Pale Ale, Coffee Oatmeal Stout
Bottled: American Wheat, Pumpkin Spice Porter, La Fin Du Monde Clone, Black IPA, Extra Pale Ale


“Beer is proof that God loves us and wants us to be happy.”
― Benjamin Franklin

Mojzis

Recipes 

I thought I had an old hard drive to harvest from but I lost it somewhere.

I got the bar to spin with the 6v, pretty good vortex. I don't have the flask so my growler will work for now. I just cant turn it all the way up because it will slide off the curved bottom. Oh well, it works. Maybe when I get a flat bottomed flash i'll hook the 12v up again.

Thanks guys for your help/advice.

Slow_Day

Recipes 

Here is mine.
I bought the Radio Shack rheostat and knob and tested it by squeezing my 3" square fan into a round cheese container. Perfect fit! Who needs an $8.00 project box and machine screws?

OK. Its a POS. But it works great! Can't wait to make my first starter.

GrogNerd

Recipes 

replaced the electronics in my guitar, wondering if a 250kΩ potentiometer will work instead of the 25Ω listed in the OP?

__________________
"It's all beer, it's all good." - Words of House Grog
"I'm only happy when I'm suffocating yeast" - Rob Grog
"Homer no function beer well without" - Homer Simpson

drinking: Sweetpea's Mock Maibock, BigHair Belgian Pale Ale, O'Rob's Irish Red, Rob's 50th SMaSH ESB, Feet & Ass Mild - bottle conditioning: CLB's Red Barley Wine - primary: DB 8 Point IPA Clone - on deck: Belgian Pale Ale