Mark's Place

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The Mash Stirrer

    I chose to build my motorized mash stirrer utilizing an old ice cream churn motor as the power source.  These motors are compact, cheap, and easily adapted to fit the top of a mash tun.  My mother-in-law got mine at a yard sale for $5.

    The unit consists of an aluminum channel as the main beam with an aluminum block on both ends to cradle the motor and to allow mounting on my mash tun.  The mash tun has two stainless steel flanges welded to the top of it with mount holes that align with these blocks.  The motor is currently held in place with black electrical tape but eventually with be secured with two small milled blocks bolted to the cradles.  The blades are made of stainless steel sheet that have been bent slightly to provide mixing of the mash.  Each blade is welded to a stainless shaft collar so I can adjust their position in my mash tun.  The down-shaft is stainless and has a square adapter pressed and welded to the top of it that mates to the start-shaped output of the churn motor.  A true star-shape could have been milled for this adapter but a square was simpler to make and seems to work just as well.  Below the adapter is a stainless shaft collar and a thin plastic thrust washer.  The shaft collar allowed me to position the adapter at the correct height during assembly and the thrust washer keeps the collar from wearing into my aluminum channel.  Support for the down-shaft is provided by a large block of high-density poly that is bolted to my channel and has a hole bored in the center.  It is basically a very long flange bearing made of plastic.  The running speed is low, as is the loading, so the bearing should work well for a long time.

    I just started using this mash stirrer and I may alter the pitch of the blades to provide more mixing but overall it worked very well.  the torque of the motor is well matched for this application.  I did have to use a spoon during initial dough-in because the motor stalled, but once everything was wet the stirrer worked without incident.

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