A slurry mixer is used in the ceramic shell process to prevent the slurry from settling and hardening. Industrial mixers have a tank that contains 30 to 50 gallons of slurry and cost several thousand dollars. On a busy month I might cast a couple of sculptures - hardly enough to justify the upkeep of an industrial unit. I did use the Shellspen system, and found it to work quite well, but the lifespan of shellspen once it is mixed is only about two months. After this time the slurry starts to settle and neeeds to be mixed before each dip. I decided to build a small slurry mixer for 5 gallon batches.

I was able to get a 1/20 hp, 300 rpm inline gear motor and a timer online from Surplus Center. A motor shaft arbor allowed me to mount a chuck onto the motor. I made a propeller from some 16 guage stainless sheet and welded it to a 1/2" stainless steel shaft. The rest of the assembly is welded from angle iron. The tank in just a 5 gallon homer bucket. The white one you see in the pictures is just screwed to the base to hold a second bucket with the slurry which is placed into it. The whole mixer cost me under $75

Here is a picture of the mixer. The assembly with the timer, motor, and switches can be slid up and down by loosening the two handles on the left. The white bucket is screwed onto the wood base. A second bucket, with the slurry in it, fits inside the white bucket. The lid has a hole cut in it for the shaft with two flaps made from duct tape to help keep the moisture in.

This is a detail of the motor/timer assembly. You can see the motor shaft arbor and chuck attached to the motor.

A detail of the motor/timer assembly from the other side. The motor is attached to a plate that is hinged so the angle of the shaft can be changed. I did this because I wasn't sure what angle would be best for mixing the slurry.

This is a view showing the propellor. The two welds on the right side of the prop are for balancing it. You can also see that the white bucket is screwed into the board with a couple of drywall screws and some washers. Another bucket with the sllurry fits into this one and can be removed and stored when not in use.