Pottery in Australia Vol 17 No 1 Autumn 1978

With some help from a letter in Vol. I, No. 1, of Studio Potter I designed
and built a clay mixer which is now in use in my studio. The mixer bin is made
from a sheet of 16 gauge galvanised iron, 3 ft wide x 4 ft 2 in long. The ends of
the bin are made by cutting four sections from a tin pineboard that is laminated
on one face. Two pieces are glued together on their non-laminated faces, giving
a solid 1 t in board. The sheet metal is wrapped around the end boards and
attached to it every two inches with I t in self-tapping screws. Next the 1 t in
holes for the shaft are cut through the ends and the whole bin screwed and bolted
into an angIe iron frame. The bearings should now be bolted to the ends of the
bin . Drill the shaft with t in x t in deep holes for the siting of the blades and
push it into place. The blades are made from 6t in x t in rods with 8 in x 1 in
x ! in flat bars welded to the top. These are now placed in the holes in the shaft
at such an angle that they just overlap each other by t in. Once their position is
set they are welded into place. The shaft should now be locked in with the bearing
collars. I used a one h.p. single phase motor with 1440 r.p.m. I used a 2 : I
reduction to the gearbox, which is a 10 : 1 ratio, and a 3 : 1 reduction from the
gearbox to the shaft, giving 24 Lp.m.
Clay mixing: a bag of dry powdered clay is tipped into the mixer with the
required feldspar and silica. I mix this dry, using a lid on the mixer to contain the
dust. Any colouring oxide is mixed with the water to give a better distribution
and added by means of a watering can. Within five minutes the mix is finished
ready for the pugmill. One load of 50 kilos of plastic clay takes about half an
hour to process, so in 10 hours I usually have a tonne. I have calculated the cost
per tonne to be $53, which is approximately 2tc per pound.
Recently I have found that putting 16 gauge wires in between the blades gives
a wedging action and improves the performance of the machine. They are attached
between parallel blades every two inches or so.
Materials:
1 x sheet galvanised iron, 16 gauge, 3 ft x 4 ft 2 in.
1 sheet laminated pineboard, 3 ft x 3 ft 3 in.
1 x 43 in x I t in bright steel shaft.
8 x 8 in x 1 in x ! in flat steel bars.
2 x UCF 208-24 (It in) bearings.
30 ft x 1 t in x J t in x i in angle iron for frame.
1 x J h.p. single phase motor.
1 gearbox at least 10 : I.
4 pulleys and belts. I used ordinary A section pulleys and belts for the motor and
gearbox but B section belts for the gearbox to mixer drive as a lot of torque and
resistance is met here.
LEN SMITH is a potter and leacher and also editor of the Palters' Society Technical Bulletill.
Len's pottery is at The King's School, Parramalla. He is willing to help anyone furtber with
information on his clay mixer; his clay body recipes have been published in tbe Technical
Bulletin, available from the POllers' Society, 20 cents plus postage.
32
NEW ZEALAND POTTER
Publishe d a t Wellington by the Editorial Committe e , ,wice y e arly
in August and De cember. Tlte yearly subscription is $ A4.50
and ,lte magazine may b e obtained from
New Ze aland Pot' e r, P.O. Box J2162, Well;n9fon North, Ne w Zealand.