Stir Plate Help

[faber]

MrFebtober, that is a nice and simple design. Thanks for the inspiration. I built my stirplate along the lines of yours, but used a variable voltage adapter (3V-12V, although it won't turn the fan below 6V), which is a great way to control fan speed to a certain extent, all the control I'll need for 1L or 2L starters.

Simple, cheap, effective.

Cheers

 

[eddie]

I have a fan hooked up to a rheostat and a 6.0VDC power supply and can get a nice little whirlpool going in a 1L flask. If I hook the fan up to a 12VDC power supply, the fan spins so fast it throws the rod and the rheostat doesn't slow the fan down enough to correct this. If I add another rheostat (so that its power supply--->rheostat--->rheostat--->fan) will i be able to use my twelve volt power supply and get a more controllable vortex which will enable me to do larger starters?

 

[RadicalEd]

Hmmm, I don't know too much about rheostats, so I can't help you there. If a double rheo was to work, a better idea would be to put a voltage regulator in front of one rheo, which should use less electricity (and cost less).

A better idea may be to design a simple voltage regulator circuit. If you can get your hands on some resistors, a potentiometer, and an operational amplifier (aka op amp), I'd be glad to post up a simple circuit diagram for you.

 

[eddie]

Hmmm, I don't know too much about rheostats, so I can't help you there. If a double rheo was to work, a better idea would be to put a voltage regulator in front of one rheo, which should use less electricity (and cost less).

A better idea may be to design a simple voltage regulator circuit. If you can get your hands on some resistors, a potentiometer, and an operational amplifier (aka op amp), I'd be glad to post up a simple circuit diagram for you.

Thank you for the offer but I've recently discovered that me and anything involving a soldering iron is a painfully bad idea. I can get a second rheostat for about $2.00 so I might just try it for SAG.

 

[uuurang]

I have a fan hooked up to a rheostat and a 6.0VDC power supply and can get a nice little whirlpool going in a 1L flask. ...

I'm piling on, but whatever , I did the same on a stirplate from HERE and HERE
I liked the simplicity of the first link and the tangible parts I could find with second.

Results, I stacked two rare earth magnets on fan in the center of fan similar to

Works well with a 2 liter erlehnmeyer flask with wort and 1.5 in. stir bar.


What I'm wondering is if magnets were stacked like this in opposition,

would this be more effective to get a strong magnetic pull then the "stacked, single magnet setup" in the first picture?

Anybody out there have experience with the difference in strength of magnetic pull on stir bar in these situations?

 

[dplin2001]

How about just using one of the selectable power supplies? I built the stir plate and it didn't work for some reason. So I just wired up an adjustable power supply through a switch and put it in a project box. It looks like it should work. I need to glue the magnets on the fan and get a stir bar. Quick question, do you glue 2 magnets on, one upside down?

Thanks

 

[Thalon]

I couldn't get mine to work very well at all with multiple magnets at opposite sides of the fan. The stir bar keeps latching onto one of the two magnets and swinging around like a lasso, which makes it very easy to get thrown. I think if I were to build it over again, I would do the single strong magnet in the middle.

 

[dplin2001]

I couldn't get mine to work very well at all with multiple magnets at opposite sides of the fan. The stir bar keeps latching onto one of the two magnets and swinging around like a lasso, which makes it very easy to get thrown. I think if I were to build it over again, I would do the single strong magnet in the middle.

thanks, thats my next step. I'll try the one strong magnet first. Maybe I could hot glue it in order to test it and epoxy the final magnet/s on depending what works the best.

 

[98EXL]

for whatever reason, mine has been throwing the stir rod around and not actually working....it's been pissing me off

 

[eddie]

for whatever reason, mine has been throwing the stir rod around and not actually working....it's been pissing me off

I believe that if the fan is moving too fast or if the stirbar is too small, it will be thrown. I've also learned that the fan must be still when you drop in the stirbar or it will be thrown.

 

[enigmabrew]

Mine kept throwing the store bought stir bar so i made my own. I took a 1/8"x 2" rollpin pushed it into some 1/8" vinyl tube and melted the ends shut. Works like a charm.

 

[98EXL]

roll pin? What is that?

 

[eddie]

roll pin? What is that?

It's a small steel bar. Kind of like a small dowel made of metal. If you took a16# framing nail and cut the ends off it you'd have pretty much the same thing.

 

[98EXL]

Oh werd, got it now