Stir Plate Fan Question

[LieutenantDan]

I'm gathering the parts to make a stir plate, I have an enclosure, sacrificial hard drive & a fan, but I am wondering if the fan I have is too small, the of the fan itself is 2.5 inches. It is salvaged from an old satellite receiver, and to me it seems pretty small. It says it is DC 5V & 1.2W, do you think this fan will do the job?

 

[Sarrsipius]

I made my first stir plate with a fan that sounds similar to what you are describing. I built it in a cigar box. The problem I had with the small fan was that it wouldn't start once you had a stir bar in liquid. It didn't have enough umph to start rotating. I had to upgrade to a larger fan.

 

[LieutenantDan]

that is my main concern, I can probably scrounge up a bigger fan. I think I need a different enclosure than I had originally planned too, the top is aluminum which will probably present problems.

 

[BrewmanCrew]

It might be too small especially if you are using it for something like a 2 l starter. You could cut the fan blades to make it a little faster.

 

[paparker21]

I reccomend cutting the can blades off - you'll reduce the rotating mass which means you reduce the required start up torque. You may have trouble starting it with the stir bar in place, but there may be an easy solution to that-- turn the fan on, then place the liquid with bar onto the enclosure. This may be enough to overcome the initial load and get it turning.

aluminum is non-magnetic, it won't cause problems.

 

[LieutenantDan]

we do 10 gallon batches & just started with starters, so I need something that can handle a minimum of 2L. I have access to old electronics so I'll just scrounge around.