What you need:
-powerful current regulator (homemade)
(an ordinary light dimmer will NOT do)
-suitable DC motor (salvaged)
-DC voltage regulator (homemade)
-Powerful yet small magnets (try ebay)
-Stirring bar (lab supply)
-heating element (homemade)
-A support for your beaker/flask (hardware store)
-A piece of material to mount everything on
Below is the schematic for the current regulating unit:
It's relatively easy to understand and build.
It doesn't even cost much, I built mine for �8 on parts.
Now for the hard part; making the heating mantle:
First a mold is created in concrete with the spiral shape for the resistor wire in it.
Below is the spiral imprinting wire glued in place on the round bottom flask (RBF):
The drawn spiral to which I formed the wire can be found above.
And below is the half-dry mold, with the flask and imprinting wire removed.
And here is the finished piece. Red clay is used to keep the resistor wire in the groove.
If you have better heat resistant molding material, please use that.
Here is a glassfiber plate I salvaged from the heater of which the resistor wire came.
It will serve well as isolation again below my heating mantle :-)
For thermal insulation I used glass wool:
The glass wool wrapped around the RBF heating mantle:
And last but not least; the unit ready for testing:
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