Tight Arse Stir Plate

[sosman]

Ok i got the magnets (thanks Doc). Gee there fun, within 5 minutes i had hurt myself with them, and within 2 hours i had a couple of small chips on the magnets. I need more self control.

If magnets were my only vice then I would have nothing to worry about.

Anyway, i have seen how people like Sosman have mounted the magnets on the fan on a metal washer. Can this technique be used with magnets like this one, or are they two strong.

In your dreams, the magnets I have are just sitting on the washer held down just by magnetic force. They don't budge at full speed. Anyway, since I have no clue what magnets you are using, it is a bit hard to tell.

Failing that i was thinking a metal strip placed as a central spoke, with the magnets at the end (not glued down, as i would like to use them for other things in the future), with a light but strong seperater preventing the magnets from sticking to each other. Is the washer a goer, or is the spoke idea better.

The great thing about DIY is that you can just try it. Then some other rainy day try something different. Don't get too dependent on "expert" opinions.

The strength of these magnets are insane. I don't believe a concave flask (sherry flagon) will be a problem at all with a stir bar.

[post="60690"][/post]​

Give it a try and let us know.

 

[pint of lager]

Kungy, and anyone else looking for magnets to play with.

Microwave ovens have very nice circular magnets in the magnetron. These are great for sticking things to the fridge, but very hard to prize back off.

Big old speakers have magnets too. But not as good as the microwave oven magnets.

Keep the magnets away from your wallet with all those nice credit cards in them.

 

[Hoops]

Kungy, and anyone else looking for magnets to play with.

Microwave ovens have very nice circular magnets in the magnetron. These are great for sticking things to the fridge, but very hard to prize back off.

Big old speakers have magnets too. But not as good as the microwave oven magnets.

Keep the magnets away from your wallet with all those nice credit cards in them.

[post="60729"][/post]​

Careful pulling apart the magnetron from a microwave, from memory they have beryllium in them as an insulator so don't breath in any dust/powder or don't go smashing them up.

Hoops

 

[kungy]

Thanks for the feedback. With some of the questions I ask, I kinda now the answers already. I just like the feedback, particularly from you wise fellows. As a young'n on this forum, and because people think Im crazy making a stir plate its always good for positive reinforcement.

I don't know about microwave ovens, but Im definitely going to crack open some hard drives for their magnets so I can play with them. I'm just a kid at heart.....

Thanks

Will

 

[Gout]

I think i recall there is huge voltages in a microwave, and not sure maybe a high volt cap in there also (eg when its turned off you still are not safe)

i could be wrong, often am but just dont hurt yourself, look into this further if you are going to pull one apart... or ask someone thats knows about them...as i dont

 

[Hoops]

Spot on Gout, there a high voltage capacitor that has around 2000V across it :excl:
There should be a discharge path for it but if there's not that will give you one hell of a boot - and probably put your heart into fibrilation and kill you <_< so probably best to leave them unless you know what you're doing.

Hoops

 

[AndrewQLD]

if anyone else is looking for rare earth magnets I have about 12 to spare from an ebay order that I should get within the next couple of days, your welcome to them for cost price plus shipping. From memory they cost me around $2.50 each.

Andrew

 

[sosman]

It was there as a preventative measure in case it had a blow out like sosman's did.

[post="57671"][/post]​

I can now report that the antifoam I used in the next starter I made works as advertised (1 drop). Of course then I was getting real paranoid that nothing was happening, especially when you scoop poofteenth of buggerall from a test tube and throw it in 200 ml of wort.

And there is no apparent detriment to the head on the finished beer.

 

[Hoops]

Order from Livingstone arrived today so I now have the stir bars, erlenmeyers, spirit lamps, Schott bottles and SOME petri dishes.
HOWEVER there were no 100mm petri dishes in the order. I have rung them and they were very appolagetic and will send them out ASAP so hopefully everything will be here by he end of the week.

Hoops

 

[BrissyBrew]

sosman if you need to offload another 100 tubes I will take them where abouts are you for pick/delivery/mail etc [email protected] if you want to email me

 

[sosman]

sosman if you need to offload another 100 tubes I will take them where abouts are you for pick/delivery/mail etc [email protected] if you want to email me

[post="62557"][/post]​

BB I want to hang on to the tubes I have. There was another thread where someone was trying organise a bulk buy of the polycarbonate tubes.

 

[Tony]

Just a little story about rare earth magnets

I ordered 4 of them, 2 for me and 2 for a mate. We are both going to build a tight arse stirrer.

I ordered 15mm x 6mm magnets and they cost us anout $8 each. That included postage to the bush so not too bad.

Bloody hell they are strong.

My mate thought it would be funny to stick one on either side of another workmates ear lobe and when they turned his ear white and drew blood he had second thoughts about his actions.

bloody hell they are strong little buggers.

cheers and be carefull with em, they can cause injury :blink:

will post some pics on mine when its done. Still waiting on the triac to come in to jacar for the speed controller im building

It will cut the AC waveform to limit the speed instead of limiting the voltage . This will help it with torque at low speeds.

cheers

 

[spog]

this thread has generated a lot of replies,discussion i reckon i might just have to have a crack at it too.one more for the mad brewers collection :beerbang:

 

[sosman]

Just a little story about rare earth magnets

I ordered 4 of them, 2 for me and 2 for a mate. We are both going to build a tight arse stirrer.

I ordered 15mm x 6mm magnets and they cost us anout $8 each. That included postage to the bush so not too bad.

Bloody hell they are strong.

My mate thought it would be funny to stick one on either side of another workmates ear lobe and when they turned his ear white and drew blood he had second thoughts about his actions.

[post="62569"][/post]​

I used 12x5mm rare earth from Alpha Magnetics in boronia and they are plenty strong enough and they were only 75 cents each (no postage). As it is, I had to put 18 mm spacers between the fan and the baseplate.

Watchout anyone who walks near your stir plate with a big belt buckle - that could do some damage (but it would be real funny to see).

 

[sosman]

this thread has generated a lot of replies,discussion i reckon i might just have to have a crack at it too.one more for the mad brewers collection :beerbang:

[post="62575"][/post]​

Go for it.

The Melbourne Brewers had a coil building (see http://www.melbournebrewers.org/wiki/JagMatic) and stir plate building day a week or two ago. Had lots of fun. If you are going to be drinking while building it, buy some spare components - the smoke comes out of them real easy.

As for the stir plate, I am building up my second starter from a slant now, CL-400 yeast which I plan to make an ozzie wheat beer. I just stepped it up to 500 ml. The first beer was from CL-50 using this APA recipe and it has turned out an absolute perler. Shame that because there is no way it is going to last until Pale Ale Mania in August.

I have been thinking of ways to make a "tight arse incubator". In the end I just bunged the fermentation fridge thermostat up to 20 deg and turned on the butter warmer - it has done just the trick.

 

[spog]

thanks sosman, a wheat beer , love wheat beers now i am really keen!

 

[lou]

hi ya all

few ideas on a tight arse incubator

i put one together many years back for an entirely diferent purpose h34r:

All you need is a plastic tub - an aquarium heater with temp control and another container to sit in the tub - preferably ceramic - like a vase or something - preferably something with a bit weight to stop it floating - (although you can just weigh it down with a heavy object)

Place water and aquarium heater and vase in tub - place petri dishes in vase and cover.

All the insualtion of the water and ceramic container provides near constant temps and you have very accurate control over the temp as well

might not work that well in summer but it does work

lou

 

[sosman]

few ideas on a tight arse incubator

i put one together many years back for an entirely diferent purpose h34r:

All you need is a plastic tub - an aquarium heater with temp control and another container to sit in the tub - preferably ceramic - like a vase or something - preferably something with a bit weight to stop it floating - (although you can just weigh it down with a heavy object)

Place water and aquarium heater and vase in tub - place petri dishes in vase and cover.

All the insualtion of the water and ceramic container provides near constant temps and you have very accurate control over the temp as well

[post="62599"][/post]​

Lou - thanks for the tip, part of my procrastination is because I want to be able to fit a 2L conical flask on stirplate in there. My fermentation fridge obviously isn't always available. As it turns out, it is holding 20 C quite nicely now, if I turn off the butter warmer it struggles.

I was thinking jaycar digital thermostat, light bulb and cardboard box if I get desparate.

 

[sosman]

Just an update. I have brewed 2 beers now working up from a slant (say a pinhead's worth of yeast) to 2L starter. They have both attenuated well and tast good. I haven't kegged the second one yet, it is at 1.010 and may still drop a point or two. It used CL-400 yeast and the grain bill most mostly wheat.

The first one was an APA and used Cl-50.

 

[user 384]

Hi Sosman

In a related thread you talked about not exceeding 5m/s for stirring. Not sure if I've done my calculations right but would this mean for a 40mm stir bar, you would need to keep the rpms down to 1590 and for a 70mm stir bar 910rpms?

How do you know what rpms the fan is turning at? Is it as simple as if the fan is rated at 3000rpm at 12v, then it would be 1500rpm at 6v? I have no idea but I bet it's not this simple.

Cheers
MAH