How to build a stir plate for less than ten quid

[photek1000]

In a way of beIng as cheap as possible how suitable would a 1.5 litre kilner jar be, would it work with a sealed lid or try and remove it and just use tin foil, suitably sanitised.

 

[Dutto]

The Kilner jars I tried had a raised bump on the inside so when the revs were increased the stirrer fell off and it took ages to get it going again. (Especially when it was full of yeast and I couldn't see the stirrer!)

If yours have a flat bottom then there is no reason why they shouldn't be suitable. :thumb:

I use a 1 litre glass jug (bought from Ikea for a quid) purely because it has an absolutely flat bottom on the inside and cover it with sanitised aluminium foil when it's in use. :thumb:

The top of the jar should never be "sealed" because the yeast will generate CO2. Kilner jars in particular are not designed to take internal pressure as they are designed to work under a vacuum.

I do use Kilner jars with their lids on to store yeast in the fridge. I cover the top with sanitised aluminium foil and then drop the lid (minus the seal) and lock it in place. It is loose enough to let any CO2 escape but tight enough to minimise any spillage. :thumb:

 

[strange-steve]

I've had glassware (beakers and flasks) off these guys:
https://www.creamsupplies.co.uk/academy-glass-conical-flask-2000ml-huge

The 'academy' stuff is good (and cheap) and boiled wort can be cooled in sink of cold tap water without the glass shattering etc.

postage is also cheap.

I have had 1litre flasks in the past but just ordered a 2litre one as for larger 1l starters is required.

That's a great price, I paid about double that

 

[strange-steve]

In a way of beIng as cheap as possible how suitable would a 1.5 litre kilner jar be, would it work with a sealed lid or try and remove it and just use tin foil, suitably sanitised.

As dutto says, as long as it has a flat bottom it'll work fine. The big advantage of the erlenmeyer flask is that you can boil the starter wort in it, plunge it into cold water to cool then pitch the yeast without any transferring, which reduces infection risk greatly. I recommend at least a 2L flask, I would have loved a 5L but they are eye wateringly expensive.

 

[braziliain]

I've had glassware (beakers and flasks) off these guys:
https://www.creamsupplies.co.uk/academy-glass-conical-flask-2000ml-huge

The 'academy' stuff is good (and cheap) and boiled wort can be cooled in sink of cold tap water without the glass shattering etc.

postage is also cheap.

I have had 1litre flasks in the past but just ordered a 2litre one as for larger 1l starters is required.

Have you had these academy flasks on a gas ring to boil the wort? Link seems to suggest no flames in contact with the flask?

 

[Dutto]

Have you had these academy flasks on a gas ring to boil the wort? Link seems to suggest no flames in contact with the flask?

Back in the days when Adam was a lad we had to put a wire gauze mesh sheet with a disc of asbestos (Yes! It really was asbestos!) in the middle on top of the tripod so that it sat between the Bunsen burner and the flask.

This correlates with the explanation ...

"These flasks can be heated - but please avoid flames touching the glass
by using a fine wire gauze between the heat source and the glass."
​

A threatened clump round the ear from the Chemistry teacher discouraged me from experimenting to see if it really would shatter if exposed to a naked flame; but I wouldn't chance it.

Here's a modern version ...

https://www.amazon.co.uk/dp/B003LXFGSY/?tag=skimlinks_replacement-20

 

[photek1000]

Cheers, will probably go for a flask, if I recall though you can't boil them on an electric hob or am I making that up?

 

[strange-steve]

Cheers, will probably go for a flask, if I recall though you can't boil them on an electric hob or am I making that up?

You can as long as it's not an exposed element.

 

[photek1000]

Nope it's under glass, so should be fine.

 

[JapanBrew]

Steve said it well. The big advantage is mixing the malt extract and water in the flask then boiling it from there. Everything is sterile. Saves a ton of time worries.

 

[Spapro]

Have you had these academy flasks on a gas ring to boil the wort? Link seems to suggest no flames in contact with the flask?

Sorry mate, not tried that, I am all electric in the kitchen.

Not tried heating these on my hob anyway - I boil my wort in a pan and then pour into the Academy glass flask for cooling, then adding the yeast.

I will have to try one of my smaller 500ml/1litre academy glass flasks for boiling wort directly on my halogen electric hob.

My new 2litre flask should arrive today - hopefully in one piece !

 

[photek1000]

Had one of those really annoying moments, the parts are coming together for a stir plate, the bar and PWM were delivered, so a quick cobble together of the fan, 12v supply and the PWM, turn on......... and nothing, fan spins fine when attached direct to the supply so i am assuming a dead PWM, need to find a meter to check it over.

I know they are only cheap but you'd still expect it to function...... mini rant over.

 

[Dutto]

Had one of those really annoying moments, the parts are coming together for a stir plate, the bar and PWM were delivered, so a quick cobble together of the fan, 12v supply and the PWM, turn on......... and nothing, fan spins fine when attached direct to the supply so i am assuming a dead PWM, need to find a meter to check it over.

I know they are only cheap but you'd still expect it to function...... mini rant over.

Most of them will only work if they are wired the right way round. Check the polarity! :thumb:

PS

If you're lucky it will still work 'cos you haven't burned it out!

 

[photek1000]

Most of them will only work if they are wired the right way round. Check the polarity! :thumb:

PS

If you're lucky it will still work 'cos you haven't burned it out!

Had a quick look at the eBay item I purchased and it stated that the diode was an LED for power-on, I wasn't getting that, so a closer examination and a quick whip around the cable connector block pins with a soldering iron and hey presto it works.

I don't know the quality of a £2 Chinese circuit board isn't what it used to be :lol:

 

[Spapro]

Had a quick look at the eBay item I purchased and it stated that the diode was an LED for power-on, I wasn't getting that, so a closer examination and a quick whip around the cable connector block pins with a soldering iron and hey presto it works.

I don't know the quality of a �£2 Chinese circuit board isn't what it used to be :lol:

What did you have to do to get it working, My bits arrived from China and I'm having similar issues but I do have a red LED on when powered up.

Fan spins when wired directly to power, but won't spin when wired through the PWM.

Power supply is 12v 5A.

Any ideas?

 

[Spapro]

Might be the power supply, 5a.

Pwm I ordered is 3a.

Will try a 2a supply, hope I haven't fried the pwm!

 

[strange-steve]

Might be the power supply, 5a.

Pwm I ordered is 3a.

Will try a 2a supply, hope I haven't fried the pwm!

If the fan works when connected directly to the power supply then the PWM is the problem. Presumably you've checked the polarity of the connections? Do you have a multimeter to check the output on the PWM?

The amperage rating on the power supply and the PWM are simply the maximum load they can handle, the fan is nowhere near that so don't worry about that. It would appear that you have a bad PWM.

 

[photek1000]

What did you have to do to get it working, My bits arrived from China and I'm having similar issues but I do have a red LED on when powered up.

Fan spins when wired directly to power, but won't spin when wired through the PWM.

Power supply is 12v 5A.

Any ideas?

Mine was an issue with at least one dry joint on the power connector, once I waved the soldering iron over it all was good.

As suggested best thing to do is check the polarity of the input and check the output witha meter.

If you're getting the LED on then that's a decent sign the unput voltage is there, on mine the brightness increases at the same rate as the knob is turned.

 

[Spapro]

Thanks chaps will check with my multimeter.

My LED does get brighter as I turn the dial up, the fan gives a little judder at around 70% dial turn as though trying to spin but never gives more than a little judder. Fan spins perfectly when wired direct to power.

Am I looking for 12volts on the live output on the PWM when dial turned to max, and lower voltage when dial turned down, is that how it works ?

 

[Spapro]

Totally stumped now

Measured with multimeter, input into pwm is 12.02v and output to fan is 11.98v with dial turned right up. Dial turned right down output to fan is 1.5v.

So pwm appears to be working correctly I think. Connected fan to power and it spins but wired back through pwm and it gives a little nudge around 70% but won't spin!

Connections look good, polarity and solder on back of pwm looks fine.

Any ideas chaps?