Stir Plate Advice Wanted

[therook]

Finally got around to having another crack at finishing this bloody project.

I still have a problem in that the bar starts to spin and then gets tossed to the side, any easy fixable solutions ?

Rook

 

[newguy]

What kind of magnet(s) are you using? The stir bar is a magnet too, with one end N and the other S. Ideal is two magnets glued to the fan, one N up, the other S up. This affords maximum attraction to the bar which means a low chance of the bar flinging off to the side. The other possibility is speed; if it's too high, the bar will fling off. Another possibility could be geometry of the entire unit - the fixed magnets should be spaced about the same as your biggest stir bar (the bar's ends should be roughly in the middle of each magnet). One last thing is magnet strength.

 

[therook]

What kind of magnet(s) are you using? The stir bar is a magnet too, with one end N and the other S. Ideal is two magnets glued to the fan, one N up, the other S up. This affords maximum attraction to the bar which means a low chance of the bar flinging off to the side. The other possibility is speed; if it's too high, the bar will fling off. Another possibility could be geometry of the entire unit - the fixed magnets should be spaced about the same as your biggest stir bar (the bar's ends should be roughly in the middle of each magnet). One last thing is magnet strength.

Newguy,

I have rare earth magnets ( 12mm x 4 mm ) as discussed in the tight arse thread one end N and the other S, i have the cct as LC described. The magnets are 50 mm apart ( centre to centre ) and my bars are 40mm and 70 mm in size It starts to spin and then gets flung to the side, maybe i need to space them further apart

Rook

 

[Fents]

Newguy,

I have rare earth magnets ( 12mm x 4 mm ) as discussed in the tight arse thread one end N and the other S, i have the cct as LC described. The magnets are 50 mm apart ( centre to centre ) and my bars are 40mm and 70 mm in size It starts to spin and then gets flung to the side, maybe i need to space them further apart

Rook

TIGHT ARSE! sorry couldnt help it mate.

 

[warrenlw63]

TIGHT ARSE! sorry couldnt help it mate.

To make matters worse it appears he has a SMALL BAR too. :lol:

Warren -

 

[The King of Spain]

Two magnets on the fan are a must. A single rare earth magnet will sit the stir plate on its end rather than lying flat.

I had a magnetic name badge from my Toastmasters club that used magnets instead of a pin. It used two flat round magnets on one side and a solid plate on the other. Needless to say my name bade is know more. The two rounds will spin a rare earth magnetinc rod at full speed. I ended up getting a smaller magnet (30mm) for somthing a bit more gentle.

 

[therook]

Two magnets on the fan are a must. A single rare earth magnet will sit the stir plate on its end rather than lying flat.

I had a magnetic name badge from my Toastmasters club that used magnets instead of a pin. It used two flat round magnets on one side and a solid plate on the other. Needless to say my name bade is know more. The two rounds will spin a rare earth magnetinc rod at full speed. I ended up getting a smaller magnet (30mm) for somthing a bit more gentle.

I am using 2 magnets

Rook

 

[The King of Spain]

I am using 2 magnets

Rook

Sorry mate.

I can understand your frustration. I fart-arsed around with mine for ages before hitting the right combo. The bottom of your vessel is dead flat? Thats about the only other thing I can think of.

 

[newguy]

I have rare earth magnets ( 12mm x 4 mm ) as discussed in the tight arse thread one end N and the other S, i have the cct as LC described. The magnets are 50 mm apart ( centre to centre ) and my bars are 40mm and 70 mm in size It starts to spin and then gets flung to the side, maybe i need to space them further apart

12mm is too small. My first test set up was with a tiny 5V fan and 10mm magnets. To borrow a phrase from a friend's dad, they couldn't pull a baby off a piss pot. My present plate uses circular rare earth magnets with an approx diameter of 20mm (3/4" actually) and my spacing is about 40-50mm center-center. With magnets, size does matter. All other things being equal (particularly the magnet's composition), a larger magnet will have a larger pull force. I think you need larger magnets. Your spacing seems right.

 

[haysie]

yeah i found my 12mm magnets not enough, luckily they came in a pack of 4 so i doubled up, my bar is short also 30mm, my magnets doubled up on a 50mm washer works good, although i have to start slow>med once i get spin crank back to near stalling. 2 LTR flask with a 1.5 ltr fermented wort still spins well, which i reckon because of the viscosity it good. Hurricanes and tornadoes are impressive but its all about keeping the yeast in suspension. Keep at it.

 

[Online Brewing Supplies]

I am using 2 magnets

Rook

Yes , Im was doing the same. But now I have a brand new Henna HI 190 M from G&G.Works way better than my home made job and doesnt throw bars.Does A 5L starter with out any problems.Thanks John at G&G.
GB

 

[haysie]

Yes , Im was doing the same. But now I have a brand new Henna HI 190 M from G&G.Works way better than my home made job and doesnt throw bars.Does A 5L starter with out any problems.Thanks John at G&G.
GB

I couldnt find your hennahi180m, what is it? link?

190, g&g being the great shop it is REALLY need to do something with their website........... its bollucks......

 

[Online Brewing Supplies]

I couldnt find your hennahi180m, what is it? link?

190, g&g being the great shop it is REALLY need to do something with their website........... its bollucks......

Sorry Its a Hanna HI (L?) 190 M.I think you may have to order one in, contact John.Yeh the web site is not what it should be!
GB

 

[razz]

In stock it appears.
http://www.grainandgrape.com.au/product_in...roducts_id=7471

 

[therook]

12mm is too small. My first test set up was with a tiny 5V fan and 10mm magnets. To borrow a phrase from a friend's dad, they couldn't pull a baby off a piss pot. My present plate uses circular rare earth magnets with an approx diameter of 20mm (3/4" actually) and my spacing is about 40-50mm center-center. With magnets, size does matter. All other things being equal (particularly the magnet's composition), a larger magnet will have a larger pull force. I think you need larger magnets. Your spacing seems right.

Just bought 2 x 20mm magnets and this was what the problem was. Spins like a beauty

Thanks everyone for your help

Rook