Sand Casting Jewelry Delft Clay

Sand casting smaller models / jewelry pieces it’s perfect. For larger pieces it becomes a bit more costly.

I used this sample for another project illustrating Delft Casting. Here the wax is being carved. I used Ferris purple carving wax because it’s hard and it’s a nice carving material.

I could have made a special frame, or bought a frame from the jewelry  supply company. Instead I just used some vulcanizing frames I had lying around.

Here the sand is packed in and I have pushed the wax model into it.

Use Talcum powder so nothing sticks.

I push with my fingers and tap it into place if the model is made out of metal.

In this picture again another model, some of the corners of sand have broken off when I removed the wax model. This is because there were areas where the wax was not properly shaped for removal, so I modified them.

Delft sand casting does not allow for under cuts, unlike rubber moulds. 
Also, the detail is not spectacular, so fancy engraving and fine detail is not possible.

Rather, what I am doing is to cast the basic shapes for the Palindrome Cannon Sculpture as I go along and then finish them off after casting.

For that purpose, I have found it exemplary.

I tap the top part down, not to hard, not to soft.

This was one of my first casts, so my locating pins were somewhat rough. 

How not to use a steel ruler.

No worry, this one has been designated as sand trimmer, cheese cutter, screw driver, chisel and scraper. A secondary benefit is you can now see the size of the metal moulding frame.

Normally I use a Stanley knife to carve a conical shape in the sand for the metal.

This was my first try and it was not very successful.

The mould did not fill all the way.

So then I made a kind of volcano shaped entry, and I also increased the sprue diameter to about ten millimeters.

This worked well, although I suspect that the increase of the diameter of the entrance from 7mm to 10mm had the most to do with success, rather than the volcano shape.

Anyway, on the project, I replaced the first one with the top two, which I also cast.

Here I only needed two copies, so I carved a wax model and cast two. The whole thing took about two hours, from wax carving to finish.

It holds the front gun platforms in place  Reference 600mm ruler.

The green flame is from the Boric acid that I use as a flux. The torch flame looks hot in the picture, but actually is is a very reducing flame because of the zinc in the brass mixture.

Casting the metal - check the green flame is still there, so my melt is still under flux as I cast.

Zinc cooks easy, so you got to look for a temperature where there is a little bit of smoke, and you swirling it in the crucible, and then a smooth gentle pour, all the while pulling the flame backwards.

After casting the metal a candle like flame burns. 

Then I tap the cast metal piece out of the top of the mould. 

Flames and smokes a bit.

That’s the top of the mould with the button tapped through.

Here is a semi finished cast. It is still getting a thread tapped in, so the nut will not be needed.