My Stirplate... Cheap and Easy Build...

Thanks for the write up Anthony. I used the Rocker Switch with LED, Rheostat and Silver Tone Knob from your list. I had some extra parts of stuff laying around so I used them and decided to make my own enclosure.

I call it my stir plate with some BLING.

Front view


Top view


And when the lights go out...

Front view


Top view

Apologies if this is a kinda stupid question ... my knowledge of electronics is severely limited :

I'm planning on putting this thing together this weekend. I just checked out the fan I have and it's 24V, not 12V (I just grabbed it off of this random old computer that was hanging around). My ac adaptor is 5.9V. Would that fact that the fan is 24V be a problem that I need to address, or should it be fine? Is there anything I should do differently?

Otherwise, thanks for the super-helpful thread!

Palefire said:

Apologies if this is a kinda stupid question ... my knowledge of electronics is severely limited :

I'm planning on putting this thing together this weekend. I just checked out the fan I have and it's 24V, not 12V (I just grabbed it off of this random old computer that was hanging around). My ac adaptor is 5.9V. Would that fact that the fan is 24V be a problem that I need to address, or should it be fine? Is there anything I should do differently?

Otherwise, thanks for the super-helpful thread!

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The the fan might not move at all. Or, if it moves, it will be quite slow, especially if you put several magnets on it. You should look for a 24V supply from somewhere (laptop power supplies are often around 20V).

I built one with tremendous success. I had an initial problem using a washer with a big hole in the center, and the HD magnet wouldnt sit right. I got it worked out though. But now, seeing some of the stir plates people have posted, like the one liquid gold posted above, i feel like i should try and do a tricked out stir plate, with bells and whistles.

you guys have made some awesome looking stuff.

avibayer said:

I built one with tremendous success. I had an initial problem using a washer with a big hole in the center, and the HD magnet wouldnt sit right. I got it worked out though. But now, seeing some of the stir plates people have posted, like the one liquid gold posted above, i feel like i should try and do a tricked out stir plate, with bells and whistles.

you guys have made some awesome looking stuff.

Click to expand...

No kidding. I'm definitely thinking of pimping my stir plate as well.

passedpawn said:

The the fan might not move at all. Or, if it moves, it will be quite slow, especially if you put several magnets on it. You should look for a 24V supply from somewhere (laptop power supplies are often around 20V).

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Cool - many thanks. Think the easiest thing would probably be to scavenge a 12V fan, since they're all around. Maybe I'll just start walking around my neighborhood with a screwdriver, in case I run into a tossed-out computer.

Thanks again.

Palefire said:

Cool - many thanks. Think the easiest thing would probably be to scavenge a 12V fan, since they're all around. Maybe I'll just start walking around my neighborhood with a screwdriver, in case I run into a tossed-out computer.

Thanks again.

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Palefire,

SF has an active craigslist community. You should post a listing asking about a dead computer. I'm sure you'll get a couple of responses.

Great directions! Even a simpleton like me could do it. I even added some personal touches. For a description and pics of my "Cheap and Easy" build go to:

https://www.homebrewtalk.com/f51/pimp-my-stir-plate-152513/

I followed your wiring directions and used your part numbers from radio shack and simply put it all together. Got the fan and power supply for free and am really happy with the results. Works like a champ! Thank you very much for the post. Love my $20.00 Stir plate.

Awesome, I looked around and found that I have nearly everything I need to get this rigged up and ready to go- cigar box for the case and an old Dell supplied the fan and magnets. The omnipresent box of electronics junk provided a power supply, switch and wire. The only thing I need to get is a potentiometer. Off to Halted tomorrow!

dumb question but the fan has a red, black, and white wire. Do you need to do anything with the white wire. Or just leave it hanging out disconnected?

Wow, the clear box with the LED fan is pretty. I might have to upgrade if the fan I got for free ever craps out on me. Until then I can't justify spending 7.99 on a fan with LED's (tigerdirect) lol. Nice job though, I am slightly jealous lol.

The white wire is the tachometer sensor wire. Not needed, just tape and store the end out of the way.

what size stir bar do you recommend with a box made by your original post instructions?

Someone mentioned using an old linksys rounter for the 12V power supply. I happen to have an extra one of these laying around (router and power supply). I was wondering if anyone has tried taking apart the router and using the female part on the router that you plug the power suppy into (not sure what the technical names for these things are).

If I could remove this from the router and attach this piece to my project box it would allow me to easily remove power supply from stir plate when not in use. Anyone tried this?

I am not concerned about the final condition of the disposed router lol. It is extra and was sitting in my random electronics box likely to never be used again.

infection, go to radio shack and you should be able to find a new female power coupler to put in your case in the appropriate size. no need to hack the old one apart. for example, if your power supply was size N:

http://www.radioshack.com/product/index.jsp?productId=2102599

if you can't find exactly the size you need, cut the end off the power supply and buy any matched set of male/female for power. they'll have quite a selection.

Cool. I might have to spend the extra three bucks and pick up one of those. This project is getting up there. That would put me at 23 dollars total.

................ forgot the stir bar ....... going on 30 lol

slakwhere said:

infection, go to radio shack and you should be able to find a new female power coupler to put in your case in the appropriate size. no need to hack the old one apart. for example, if your power supply was size N:

http://www.radioshack.com/product/index.jsp?productId=2102599

if you can't find exactly the size you need, cut the end off the power supply and buy any matched set of male/female for power. they'll have quite a selection.

Click to expand...

So I bought piece mentioned above. I'm not completely sure that I have it wired correctly though. It has three prongs. One labeled "center pin", one labeled "shell", and a third that has an arrow pointing from it back to the "shell" prong. This prong is labeled "normally closed" switch.

From what i could find online, I connected a black wire to the "center pin" prong and a red wire to the "shell" prong and proceeded as the O.P. described.

Anyone know what I did wrong here?

Yeast infection, the center pin is usually positive, so in this case you want to wire it to the red wire.

Thanks! Got it working. Now just waiting for my stir bar to come in so I can make some final adjustments and get some yeast going.

yes wiring the positive side to the shell will open you up to shorting/grounding possibilities which would be bad. hot in the center, ground on the outside.

Just built this.

Quick and easy. I even got to gloat to SWMBO about how I really DID need to keep all of those old PC parts for something useful

For some reason though (perhaps magnet is not centered enough) it throws my 1.5" stir bar, but the 1" seems fine (as long as I keep the speed up)

Bottom line, it was easy, cheap and does what it needs to do

Glad to hear everyone is fairing well with the write up.

Hey got a quick question. I Just built one of these, and installed a 1 inch by 2 inch long rare earth magnet on the fan....when I install it in the box, and sit my 2000ml flask with 1 inch stir bar on it....and turn it on..my stir bar stands straight up vertical. It doesn't lay horizontal and spin..it stands up and spins..is my magnet too strong?? or what????

Dan

The magnet is too long for use with the small 1 inch stir bar. The bar will slide to one pole or the other and either get thrown immediately or it will do what you are describing. You could try it with a two inch bar or a shorter magnet. Ideally, the poles on the magnet should be spaced about the same as the poles on the stir bar. The stir bar has a magnet embedded in it that has a north and south pole just like the magnet on the fan.

ah...I see..Ok..I'll give it another go.

Dan

I don't think it's a length issue. I think the magnet has poles on the top/bottom, not the ends like the stir bar...

Niederhofer said:

I don't think it's a length issue. I think the magnet has poles on the top/bottom, not the ends like the stir bar...

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That is correct.
Here is a great FAQ http://www.kjmagnetics.com/faq.asp
This is also where I ordered my magnets, I've used them for everything from suspending tea strainers in my cornie kegs to making my stir plate. No idea if they are the best price but I liked the FAQ and that I could order singles.

Good luck!

Niederhofer said:

I don't think it's a length issue. I think the magnet has poles on the top/bottom, not the ends like the stir bar...

Click to expand...

Yeah, that would explain it. I was thinking that he had bar type magnet with the poles on the ends. Might not work at all with only a single magnet of that type. I use two disc type magnets on mine.

TommyBoy said:

Doesn't the vortex help aerate the starter?

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Surface area is the name of the game in aeration. You want a nice deep vortex that has rippling on as much of it's surface as possible. play with water first, but keep in mind that the mini-wort will be much denser so you will have to adjust some.

so you guys are saying I need two smaller magnets on opposite sides of my fan, rather than one long one? I'll give that a shot if so. it's pretty funny to actually watch the stir bar stand up on end vertical and spin that way. but I'll give a couple of smaller magnets a try to see if I can get my stir bar to lay flat and spin properly.

Dan

flyweed, make sure that the 2 magnets are lying on the fan in oposite polarities. one + and one - up, and you'll have to play with the spacing to get it to work for your stir bar (especially if you plan on using multiple stir bars).

flyweed said:

so you guys are saying I need two smaller magnets on opposite sides of my fan, rather than one long one? I'll give that a shot if so. it's pretty funny to actually watch the stir bar stand up on end vertical and spin that way. but I'll give a couple of smaller magnets a try to see if I can get my stir bar to lay flat and spin properly.

Dan

Click to expand...

I've built a few stir plates with 3 HD magnets stacked to get a 1/2" bar to spin full speed in a 4L flask. Click on my gallery to see higher res versions of these pics if they don't come out right.


I was always a little disappointed that my 2" would always get thrown. Then I built another strirplate with small round disk magnets. These magnets are about 1/2" across and maybe 1/8" thick (looks like a large watch battery).

I make 2 stacks, with 3 of them in each stack. The stacks must have opposite polarity for this to work!. The distance between the stacks is about 1.5" (I think). I can now spin that 2" bar. I hotglued a piece of tin (cut from a peanut can) to the fan so I had a place to glue the magnets down.

BTW, the magnets in this second picture below are held by electrical tape. I took this pic during testing and didn't take one after the final glue assembly.

flyweed said:

so you guys are saying I need two smaller magnets on opposite sides of my fan, rather than one long one? I'll give that a shot if so. it's pretty funny to actually watch the stir bar stand up on end vertical and spin that way. but I'll give a couple of smaller magnets a try to see if I can get my stir bar to lay flat and spin properly.

Dan

Click to expand...

K&J sells single magnets with both polarities along their center axis. I haven't used them, however I'd bet they would work as well...

Fly,

You can use two button magnets or one single bar magnet, both will work OK.

Just make sure that your button mags are arranged with north pole up one side and north pole down on the other.

I think the reason your stir stood straight up is the fact that your drive magnet is magnetized through the short axis instead of the long axis. With a bar magnet you want the poles to be on the "ends" of the bar and not the "sides" if you get my drift.

I happen to have most of the Radio Shack components for this build already (leftover from an EE class I took years ago). I have one Pot, but it says 500 Ω (500 Ohms) on it. Will this work? I expect not, but I'd like to hear opinions on this.

im sorry if someone already asked this question, but I was building this today and when I finished, the potentiometer wouldnt turn it completely off. is that correct? it seems to be spinning very fast even at its lowest speed.

andersonimes said:

I happen to have most of the Radio Shack components for this build already (leftover from an EE class I took years ago). I have one Pot, but it says 500 Ω (500 Ohms) on it. Will this work? I expect not, but I'd like to hear opinions on this.

Click to expand...

Sure, like this (click on pic for big version):

v2comp said:

im sorry if someone already asked this question, but I was building this today and when I finished, the potentiometer wouldnt turn it completely off. is that correct? it seems to be spinning very fast even at its lowest speed.

Click to expand...

The potentiometer doesn't work as an on/off switch. It will only vary the voltage from the DC power supply going to the fan.

If anyone has a Harbor Freight Tools near by they have some real inexpensive magnets that are pretty strong. $2 for a pack of 10 vs the $2 for a pack of two smaller ones at radio shack.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=67488

Also I just ended up buying a 120mm case fan for $9 at the local computer store down the street. It JUST fits in the radio shack 5x7x3 project box width wise. In fact it snaps into the lid it's so tight. I'll get a bar or two ordered soon to check out what size I want to use.

Anthony_Lopez said:

The potentiometer doesn't work as an on/off switch. It will only vary the voltage from the DC power supply going to the fan.

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And also, if you're just hooking up the pot directly to the power supply and the output (in other words, without using the LM317 circuit as shown), then you might risk burning it up if you try to put it at the fan's lowest setting. Essentially, it's trying to resist a lot, and it will get "hot!"