Stir plate

[RichardM]

Or a magnet

I used a magnetic today and there is no stir bar in the fermenter!

 

[muppix]

I wonder how many magnetic stir bars accidentally get flushed down the loo?

 

[Galena]

I wonder how many magnetic stir bars accidentally get flushed down the loo?

Why have you swallowed yours?

 

[Slid]

Why have you swallowed yours?

LOL, that's a good one, and still not the end of the Sunday lunchtime session!

 

[foxbat]

I wonder how many magnetic stir bars accidentally get flushed down the loo?

There's one in the u-bend of my utility room sink

 

[Slid]

Just got my order in for one of these. On to the next level!

 

[muppix]

Why have you swallowed yours?

Not yet, but I'm still a beginner.

Just wondering since I'm using a converted bathroom as brewery, and The Big Porcelain Telephone makes a rather handy trub-dump.

 

[Galena]

Not yet, but I'm still a beginner.

Just wondering since I'm using a converted bathroom as brewery, and The Big Porcelain Telephone makes a rather handy trub-dump.

 

[jayk34]

I can't seem to get the magnetic stir bars to rotate properly. At the minute the stir bar is rolling in position. Have spent all morning trying different configurations of magnets placed on the top of the computer can but can't get it to work properly. Anyone know how to orientate the magnets.

 

[Galena]

I can't seem to get the magnetic stir bars to rotate properly. At the minute the stir bar is rolling in position. Have spent all morning trying different configurations of magnets placed on the top of the computer can but can't get it to work properly. Anyone know how to orientate the magnets.

All I do is tilt the flask so you can see the magnet on the edge of the flask, offer that edge to the centre of the plate and slide the flask into position, start the rotation slowly and check it is rotating and then increase speed to just get a small vortex. Never had a problem really.

 

[jayk34]

All I do is tilt the flask so you can see the magnet on the edge of the flask, offer that edge to the centre of the plate and slide the flask into position, start the rotation slowly and check it is rotating and then increase speed to just get a small vortex. Never had a problem really.

Have tried that. It just rolls at fast pace but does not doing to create a vortex. Going to bottle up a beer and then have another attempt at it.

 

[RichardM]

Have tried that. It just rolls at fast pace but does not doing to create a vortex. Going to bottle up a beer and then have another attempt at it.

It should spin, not roll. I don't really understand what you mean by "just rolls". Are you using a former PC fan as the basis for your stir plate? Is the magnet stuck to the centre of the fan?

 

[The-Engineer-That-Brews]

I use a couple of small round rare earth magnets, each stuck opposite ways up to each end of a bit of steel strip mounted on the fan - that produces a good strong field.

 

[RichardM]

I use one magnet, salvaged from a hard disk, glued to the middle of the fan. The second magnet is now used to "catch" the stir bar when pouring the starter in to the fermenter.

 

[The-Engineer-That-Brews]

Agreed! The ‘old PC fan’ approach works a treat for me and I have a suspicion that might even be what is inside some of the cheaper commercial stir-plates. I do find some kind of speed control is necessary though to avoid the bar skipping out.

 

[RichardM]

Agreed! The ‘old PC fan’ approach works a treat for me and I have a suspicion that might even be what is inside some of the cheaper commercial stir-plates. I do find some kind of speed control is necessary though to avoid the bar skipping out.

Yes, my build includes a speed controlller. Something cheap off ebay sold as a PC fan speed controller, with a rotary knob that to wind the speed up or down.

 

[Galena]

Perhaps you could film it and upload the video here?

 

[The-Engineer-That-Brews]

Anyone know how to orientate the magnets.

If you are using individual magnets @jayk34 then I would recommend orienting them like this (sorry, best photos I can do without disassembling).
One of the magnets is 'north' up, and the other is 'north down'; and they are stuck to a strip of steel and held in place with hot glue

 

[jayk34]

It should spin, not roll. I don't really understand what you mean by "just rolls". Are you using a former PC fan as the basis for your stir plate? Is the magnet stuck to the centre of the fan?

I'm using an old pc fan with a magnet from a hard drive. I stuck it on top of a fanta bottle lid to stop the magnet didn't stop the fan.

It's not in a case it anything at the minute as I wanted to get it working before putting into a case and tidying up leads etc.

Here is a video

 

[The-Engineer-That-Brews]

Fan's running far too fast mate - that's your problem
Also, you need to start with the fan stationary, then get the stir bar in position and being held by the magnets before you turn the power on