Sand Riddle (sieve)

When I started out with my foundry I had to find a way to sieve the sand used to make my green sand. At first I used kitchen sieves and fly screen or shade cloth. These worked OK, but I needed something finer too get better results, and make it easier to sift larger quantities of sand. I made a rectangular frame out of timber, open at the top and bottom and hung it to a frame with small chain. I then made an angle iron frame to go around the bottom and hold the fly screen in place. The idea was if I wanted to change the size of the screen, I could remove the frame and fit finer or courser mesh. Once it was suspended by the chain it was a matter of shaking it back and forward to sift the sand or powdered Bentonite. I used this for some time, but it became a bit tedious shaking it by hand, also I needed something finer still.

       I happened to come across some very fine stainless steel mesh that was just what I needed. I don't know what size mesh it is as it is too fine to count the wires. The sand is nearly as fine as dust when it is sifted, finer than beach sand. I then decided there had to be a better way to shake it than by hand! Basically I needed some way to shake it with a motor. I found a 12v car heater motor, a car water pump bearing and a suitable weight to mount off-centre so it would shake the sieve. I made a wooden mounting for the motor and water pump and joined the motor shaft and water pump bearing with rubber tubing and a couple of clamps so there would be no sideways force on the motor bushes from the weight. I then bolted a plate to the pulley boss of the water pump and bolted a weight (old cast iron pulley) on the plate to the side of the bearing. When the motor turns, the sieve, which hangs on four small chains, shakes the sand through into a plastic tub below. I then had the idea to put a ply wood top on the frame that supported the sieve and use it as a table in my foundry. This is now bolted to the wall and the sieve and tub are under the ply wood top which is now used as a bench beside my moulding table. All it takes is a bit of thought to find ways to make better use of things you make. Sometimes these thoughts don't happen until you have already built something, and then you have to modify what you have already done to make it better! Below are some photos of the sieve showing how it was built. Next I will describe my other sieve which is designed loosely around a sand riddle used in foundries. This is used to sieve and fluff up the green sand after it has been through my muller.

     

         This is the frame for the sieve with the ply wood top I added later.

This shows the sieve itself with the angle iron frame to hold the mesh.

Here is a view of the top showing the motor mounting.

View of motor mounting with coupling to water pump bearing and the pulley I used as the weight.

The sieve mounted underneath the bench by four small chains, one on each corner. The chains are attached to the bench by small "D" shackles so the sieve can be removed to clean out the residue.

Front view shows the chains, "D" shackles and the opening for the sand.

Side view with the plastic tub for catching the sieved sand.

Front view with the tub in place. The sieve hangs into the tub so it will catch the sand as it is sieved, but the tub can be removed by tipping it up to clear the sieve.