What Happens When You Send Waxes to be Cast?

At Stem and Seed Jewellery Australia, we take great pride in providing service to our local customers, artists and businesses alike. In order to give an even greater experience, we've written this blog to help you understand what happens after you send your wax piece in to be cast using lost wax investment casting.

We often get asked if we print our jewellery, and the answer is no, not directly. There isn't yet a way to print directly in precious metal. Below we go into the details of our lost wax investment casting to give you an idea of what exactly happens to your waxes when you send them in to be cast.

 

Spruing

Spruing is the process of attaching metal feeders to the jewellery. What most don't know, is that this process truly takes hours and a steady, skilled hand. When casting, without a sprue, there's simply no path for the molten (liquid) metal to flow into the design.

When using a 3D workflow, you can simply make the sprues part of the design, but when using wax, you must make them and attach them by carefully melting the wax and securing the sprue to the wax, then to the tree.

Here at Stem and Seed Jewellery Australia, we are well versed in both methods of spruing, and we love to help you by spruing the pieces for you, helping ensure a flawless result. 

 

Sprue Tree

In the above example, there was only one piece being made. Below, you will see an example of a sprue tree. You make a sprue tree when you need to cast more than one piece at a time.

 

Investment and Burnout

When your waxes are sent in, the sprue setup is created and the sprue tree is perfected. Before anything is put into the furnace, the waxes are covered in a special casting plaster called investment powder. Confusing, but this has nothing to do with money, day trading nor stocks.

 

 

Investment powder is used to make a special plaster that holds the waxes securely and with a high level of detail, so that the waxes can burn away into nothing, leaving behind a gap. This process is called burnout.

Your piece made of wax is burned away, which leaves a hole in the shape of your piece, which can then be filled with molten metal using vacuum casting. A strong vacuum (-30 inHg, inHg is read: "inches of mercury") is used to create a pressure gradient, this difference in pressure helps draw the molten metal into all the details.

A precise measurement of investment powder to water, the delicate handling of the flasks once they are full of powder, the delicate burnout process, the gentle melting and finally the tight seal when creating the pressure gradient is the secret to how we create our highly detailed casts.

 

 

Thanks for reading and I'll catch you in the next one! Any questions, please get in touch, I'm here for you.