My homebrew stirplate

[JoeRags]

Having some problems with mine... I built the LM317 voltage regulator no problem. I used two magnets from one hard drive, but my stirbar wont center itself. The magnets are glued centered and as far apart from eachother as possible.

My 2 inch stirbar seems to work best in the 2000mL flask, but it rides funny. How come it wont center itself? Because of this, I can get it spinning, but nowhere near as fast as needed to pull a cyclone.

Should I not have the magnets glued on opposite ( one N up, and one S up)?

Thanks

*edit... attempting this method

http://www.brewboard.com/index.php?showtopic=80139

just waiting for epoxy to dry. I'll report back soon.

 

[Seabee John]

One magnet should be strong enough... I believe the magnets from hard drives have a pos / neg at each end of the mag. So with TWO mags your stir bar may not know which mag to center on. Try one mag and get back to us.

 

[JoeRags]

I tried it as shown in the link I posted above, two magnets glued together, then centered on the fan.

Working great!!!!!!!!! :rockin:

My 1" stirbar seems to work best, I can go right up to full speed with it. The 2" and the 1-5/8 both get tossed.

Excellent device! Cant wait to use it!

 

[Chriso]

I'm on only 1 magnet right now and I think I can't get my fan rpm low enough. If I hold the glass directly over the magnet, it kinda sorta works. But only if I brush against the fan to slow it down.

 

[JoeRags]

I'm on only 1 magnet right now and I think I can't get my fan rpm low enough. If I hold the glass directly over the magnet, it kinda sorta works. But only if I brush against the fan to slow it down.

What are you using as a speed controller?

 

[Chriso]

What are you using as a speed controller?

SilverStone inline speed controller, came with the fan. Goes 800RPM - 2400RPM. I'm trying to think of some way to slow it down. But the controller has a seperate circuit than the power does. Both circuits end at the fan.

 

[JoeRags]

If you have any electronics experience, I'd recommend building the LM317 speed controller... its very simple, and works great. I had most of the parts lying around, though I had to improvise a bit since I couldnt find a 1k resistor.

 

[kjones]

is it just me or are the pictures not workn on this post anymore?

 

[Seabee John]

is it just me or are the pictures not workn on this post anymore?

I've noticed that I've had to repost some of my PICs after the site got revamped tis last week or so... look in your gallery... My stuff all had a different address

 

[SourHopHead]

Anyone try adding an inline fuse? Reason I ask is I am not allowed to burn the house down. I am planning on using a power jack to plug my 12v/500mA power supply into, because I do not want to hardwire the power. Ordering my parts tomorrow...

Absinthe > Coffee Table

 

[Scimmia]

I don't think anyone's mentioned it, but I don't see a problem with adding an inline fuse. I would probably be a good idea if the power supply doesn't have any kind of protection in it.

 

[98EXL]

Here's my problem:

I have this really sexy stirplate I made out of a snazzy cigar box.....the works. I can't get the damn bar to stay on the magnets...it flings it off! However, if I put the bar on the box, it works like a champ......any ideas? I've used a 1l flask and a .5 gallon growler....both to no avail

 

[Chriso]

98exl, did you just mirror the original setup, or did you customize at all?

I finally got mine working with the pre-assembled SilverStone fan - I had 2 problems.

1st, I had to add in another potentiometer to get my RPMs to an acceptable range. I used a volume pot out of my broken electric guitar - but I installed those pots myself 3 years ago, they aren't standard sizes or resistances. I thought it was a 25K ohm pot I put in? Anyways, I mounted it inline between the power cord + and the fan. Then the fan controller is on a seperate circuit. I'm sure that makes no sense. But anyways, now I start the stirplate with both knobs at 0, raise one, then the other, then one, then the other. I can get a decent vortex with water, but haven't tried with wort yet. This is a 1 3/8" stirbar by the way.

2nd, my hard drive magnet sucked, so I went to JoAnn fabrics and picked up a pack of 8ct 1" ceramic magnets. Glued 2 on each side of the fan hub, and it worked perfectly. Neither the HDD magnet or the Radio Shack tiny Rare Earth magnets did anything.

 

[98EXL]

did I customize it....of course I did!

I am really thinking it's the magnets....when I ghetto-fied it all up it worked great, but in the box, not so much....

I need to post up my damn pics, it's really sweet looking...but just not working....so JoAnn fabrics huh? I should try that out

 

[Chriso]

I would think Hobby Lobby carriesthem too, but JoAnn's is 20 minutes closer to me. I found them near the "woodworking-type-hobby-supplies" section. At least, as close to woodworking as JoAnn's has. If you're near the paint and wood glue and scrapbooking, you're probably close. The store clerk I asked had no clue if they had magnets or not.

 

[98EXL]

I would think Hobby Lobby carriesthem too, but JoAnn's is 20 minutes closer to me. I found them near the "woodworking-type-hobby-supplies" section. At least, as close to woodworking as JoAnn's has. If you're near the paint and wood glue and scrapbooking, you're probably close. The store clerk I asked had no clue if they had magnets or not.

chriso > JoAnn's Store Clerk

 

[Scimmia]

Another thing to check is that the bottoms of your vessels are flat. If they're not, you're going to have a hard time using them. If it works without the flask, but not with it, the first things I would check would be that and that the magnets are close enough to the bar.

 

[Vels]

Go up in speed alowly so the liquid have a moment to accelarate, that can remedy throwing of the stirbar.
Also move swift past speeds where the stirbar start to wobble and eventually trow after some seconds, it is very clear from the sound of it when it start to wobble.
Make sure that your container is centred, if you stir off center, that that will throw the magnet too. You can hear when you move the container around where center is, then it will stir almost quiet and make a perfect dimple/vortex depending on speed.
If you have 2 magnets on your fan setup make sure they have different poles op 1N and 1S.
I use 2 magnets with 6-7 pound holding power each, that seem just right for my setup stirring ½ gallon.

Have you tested holding power through your cigar box setup? maybe material/distance takes too much power away ?

This show holding power of the magnets i used, and it also show why distance is important

For the Metrically challenged 4kg=8 pounds and 6 mm= 1/4 inch

And yes, at the distance from magnet to container bottom where the stirbar is so great that holding power is really low, but still it does matter if power 0,10 or 0,15pound per magnet (50 % difference)

Just my $.02

Cheers
jakob

 

[sirsloop]

I tore a 120mm fan out of a toasted pc power supply, and ripped out 4 magnets out of a pair of toasted scsi drives from work. I've got some spare plexiglass at home and access to a virtually unlimited supply of 5V wall worts. I have some of those speed control thingys for fans layin around... so i'll use those to dial in the speed. I'm gonna toss one together maybe over the weekend. It should be a fun little project!

 

[sirsloop]

****... I got bored waiting for this stir bar to come in so I turned my hard drive into a speaker

http://homebrewtalk.com/showthread.php?p=549799#post549799


[youtube]M21kWLqH77w[/youtube]

 

[Chriso]

+1000! Go Sirsloop!

(Wanna tell me how to fix my electric? Its wiring is toast.)

 

[sirsloop]

lol... I'm no electrician... took me a little while to find the right leads to solder to.

 

[kjones]

I just got mine all done and together...but i can't get mine to slow down to a crawl actually when the pot is all the way down or not even all the way down the fan completely stops spinning i am about to go read my voltage at the the lowest setting... anyway my stir bars come tommorow so im gonna give her a spin

 

[kjones]

well it does vary from about 1.28v to 12 but the fan will only turn at a min of about 5.2 volts sseems to fast to not sling the stir bar owel we will find out

 

[sirsloop]

I just got mine all done and together...but i can't get mine to slow down to a crawl actually when the pot is all the way down or not even all the way down the fan completely stops spinning i am about to go read my voltage at the the lowest setting... anyway my stir bars come tommorow so im gonna give her a spin

Move the fan farther away from the magnets. The force of the magnets is too strong and is waxing your fan.

 

[max4677]

Silly question:
Is it possible to just use a regular old 120V desk fan and put a light dimmer switch in-line instead? I have a feeling that this has been asked already but my search-fu is failing me.

 

[kjones]

Well, I got my stir bars in today and and none of them will work they just kind of spin a little by like following mags on one side of the fan then sling off. I wish Mrsalty the original poster would chime in... guess hes not around anymore or maybe yuri someone with some experience building these things i pm both with no response well i guess if you two see this reply or someone elso that knows something i would be greatly appreciative for some info...

by the way... the magnets i used are 4 1/2 dia. x 1/8 thick rare earth magnets. there are 2 glued together on each side

 

[sirsloop]

are the reverse poles sticking up?

 

[Bearcat Brewmeister]

+1 on sir. Definitely sounds like the magnets on both sides have the same pole facing up. With those size magnets, you should have no issues if they are oriented correctly.

 

[sirsloop]

Originally Posted by camiller

That one is out of stock currently, I'm considering this one http://www.newegg.com/Product/Produc...82E16835200021

Cheaper also.

That rosewill fan is a POS! The controller that comes with it is nice. If you put a hard drive magnet on that fan it locks up the blades from turning. I ended up ditching the fan and just using the controller on a beefier fan that I had laying around. If you end up using that controller, a 9V power source is just about right for low to stop the blades and high to spin a 2000ml flask at an insane rate. I tried a 5V and it was ok... pretty good for like 1000ml. I put on a 12V source and it would make a MASSIVE vortex from top to bottom of a 2000ml flask, but at low the fan moves so its hard to get the bar centered on the magnet without killing power.

I'm going to work on fine tuning my setup now... but it currently includes a beefy 12V 120mm fan, machine screws to lift a 120mm fan holder up above the magnets, three hard drive magnets stacked on the fan, 1-3/8" stirbar... and a 9V source. I'm not 100% sure how I'm going to hold it all together yet, but so far I just cut a piece of spare plexiglass in a 140mm square so it can fit on top of the fan, padded with that kitchen no-slip stuff. Works good... pics/video tonight probably...