Beer Forum

I posted how I built my stir plate 2 or 3 years ago. Well I am sick of it, I get pissed just thinking about it. I spend an hour trying to get it started and just bumping it, it stops. I need a new design. Let me know how you guys built yours and how well they work.

Have you tried a smaller stir bar? I had a 1 1/2 inch one that kept getting tossed, and went to a 1" that starts much easier and is touch to toss off.

larry78cj7 wrote:I posted how I built my stir plate 2 or 3 years ago. Well I am sick of it, I get pissed just thinking about it. I spend an hour trying to get it started and just bumping it, it stops. I need a new design. Let me know how you guys built yours and how well they work.

I built the Radio Shack Project Box and computer fan design. But I didn't use a hard drive magnet. I went with 2 little rare earth magnets on the washer. I start it low and ramp up the speed until about 3/4 of the way. Never throws on me unless I try to make it spin too fast. I'm using a 2" bar.

larry78cj7 wrote:I posted how I built my stir plate 2 or 3 years ago. Well I am sick of it, I get pissed just thinking about it. I spend an hour trying to get it started and just bumping it, it stops. I need a new design. Let me know how you guys built yours and how well they work.

Clearly you have spent more in time, anger and frustration than a used industrial strength stir plate would run you on ebay.

I think I spent about fifty bucks on this and it will probably outlast me:

BeerPal wrote:

larry78cj7 wrote:I posted how I built my stir plate 2 or 3 years ago. Well I am sick of it, I get pissed just thinking about it. I spend an hour trying to get it started and just bumping it, it stops. I need a new design. Let me know how you guys built yours and how well they work.

Clearly you have spent more in time, anger and frustration than a used industrial strength stir plate would run you on ebay.

I think I spent about fifty bucks on this and it will probably outlast me:

Do you have any issues w/ too much heat from a stir plate like that? I hear they throw some serious BTU's.... you ever check the temps of your starters?

ApresSkiBrewer wrote:Do you have any issues w/ too much heat from a stir plate like that? I hear they throw some serious BTU's.... you ever check the temps of your starters?

I have never used a thermometer to check the temp of a starter. I do feel the flask frequently however and have never noticed it to be warmer than expected. The actual plate is separated from the motor by about an inch of open air space. The magnet is mounted on a shaft to get it close to the underside of the plate and away from the body of the device. So it is designed to reduce unwanted heating during operation.

I used the circuit diagram on this page:

http://forum.northernbrewer.com/viewtop ... 5&start=15

Components used were an 80 mm computer case fan, a DC power supply from an old telephone, a project box from radio shack, some hardware, and the various electronics from that diagram. This circuit is a little more complex than just connecting the pot in series with the fan, but the pot should last a lot longer with this design. It is capable of using a 1.5" stir bar at full speed which generates a small dimple in 5L of water, and probably costs around $25-35 depending on where you buy the stuff. There are a couple of things to consider when you build it:

1) magnet placement: I've found that two magnets spaced on opposite ends of the fan work much better than one. I had one and it would work with the 1/2" stir bar, but the 1" would get thrown at high speed and the 1.5" would get thrown at minimum speed. When I added the second magnet, it worked like a champ. I just glued a washer to the fan hub and stuck the magnets to the washer.

Here's a pic of the fan before I added the second magnet. I just replaced the nut with an identical rare earth magnet.


2) magnet to stir bar spacing: if you use rare earth magnets and have the fan near the top of the box, you could be pulling down too much on the stir bar, which makes it spin slower or not at all. You could adjust this with hardware, or just put a pot holder under the flask to increase the distance between the magnet and the stir bar if it's too close. It varies depending on the stirring vessel you use (jug vs. erlenmeyer flask for example).

Here's another post of various setups:
http://www.brewboard.com/index.php?show ... m317t&st=0

Nyakavt wrote:I used the circuit diagram on this page:

http://forum.northernbrewer.com/viewtop ... 5&start=15

Components used were an 80 mm computer case fan, a DC power supply from an old telephone, a project box from radio shack, some hardware, and the various electronics from that diagram. This circuit is a little more complex than just connecting the pot in series with the fan, but the pot should last a lot longer with this design. It is capable of using a 1.5" stir bar at full speed which generates a small dimple in 5L of water, and probably costs around $25-35 depending on where you buy the stuff. There are a couple of things to consider when you build it:

1) magnet placement: I've found that two magnets spaced on opposite ends of the fan work much better than one. I had one and it would work with the 1/2" stir bar, but the 1" would get thrown at high speed and the 1.5" would get thrown at minimum speed. When I added the second magnet, it worked like a champ. I just glued a washer to the fan hub and stuck the magnets to the washer.

Here's a pic of the fan before I added the second magnet. I just replaced the nut with an identical rare earth magnet.


2) magnet to stir bar spacing: if you use rare earth magnets and have the fan near the top of the box, you could be pulling down too much on the stir bar, which makes it spin slower or not at all. You could adjust this with hardware, or just put a pot holder under the flask to increase the distance between the magnet and the stir bar if it's too close. It varies depending on the stirring vessel you use (jug vs. erlenmeyer flask for example).

Here's another post of various setups:
http://www.brewboard.com/index.php?show ... m317t&st=0

How come I didn't think of a washer? That must make it a lot easier to balance. Where did you get the rare earth magnets, I looked in town and couldn't find any? Thanks for the help