December: Casting & Granulation For Jewellery Making

Introduction To Casting & Granulation

Kim gives you a basic introduction into casting, showing you an easy technique on how to cast shapes using a charcoal block. Kim also shows you how to create silver spheres, known as granulation.

Using A Potato Instead Of A Charcoal Block?

Kim shows you how you can replace a charcoal block with a potato! Showing you how to make silver balls and a sweet cast heart.

Organic Silver Casting Tutorials With Pasta, Rock Salt, Lentils & Water...

Kim shows you a tutorial on organic silver casting! Including small scale silver casting into rock salt - plus spaghetti and water casting.

Casting Crucibles Plus Important Health & Safety Information

Find out more about the crucibles you can use for casting plus important health and safety information for casting metal in the video above.

Kim - "Crucibles! They are containers to hold metal while melting it and transporters for then pouring that molten metal into a mold. They come in many shapes and sizes and all the ones I'm going to show you are for melting fairly small amounts of metal.

Larger amounts of metal are melted in large vase shaped crucibles in a super hot furnace rather than with a blowtorch. I prefer a crucible with a fairly flat surface as the heat can get to the metal easier. If you don't have a crucible and are only melting very small amounts of metal with a small torch, you could do that by carving a small crucible shape out of a magnesia soldering block or by making a little channel in a charcoal block and propping one end of the block up so the molten metal rolls into your mold. Always ensure you're working in a safe area so if you drop any molten metal, it is not going to fall on a flammable surface or you!

Molten metal is hot. VERY HOT. If it falls onto a surface that isn't fireproof, you could easily cause a fire. If it falls on you, you will burn yourself, badly. Before we start, you need to plan how you can minimise these risks and deal with them if they ever do happen. Creating a fireproof safe work area is a must. You will need multiple fire bricks, kiln shelves or similar so you have a safe area in case you miss while pouring the metal and remember you'll need a safe, heatproof surface to put your crucible down once you've finished.

The exact personal protection measures will depend on exactly what you want to do and were. There's a big difference between melting a tiny amount of silver into little balls compared to heating large crucibles in a furnace and lots of variables in between. It depends on how much you're doing, how often, in what environment and your overall health. Some things to look into and consider are, fire safety, clothing (synthetic clothing can melt onto your skin or catch fire from a tiny spark), eye protection, fume extraction, respirator masks, metal fume fever and the fumes different metals give off when molten. Do some research and decided what you're happy to do and how in your specific workspace."

Sand Casting Tutorial

The results with Kim & Kerry

Kim and Kerry discuss how they got on with casting, reveal the finished pieces and the difficulties they faced along the way...

Cuttlefish Casting Tutorial

Kim - "Next up for Make It Month 12 is casting into a mold. You can make 2 part molds from a variety of things which you then pour molten metal into. One popular choice is cuttlefish casting. You use a bone from a cuttlefish and carve or press your design into it. This bone was found on a beach but you can also find them in pet stores as budgies like to eat them.

You prepare your mold by cutting the cuttlefish bone in half using a jewellers saw. They are usually soft inside so you can smooth the inner surfaces by rubbing them together. You won't want to breathe in the dust so make sure you wear a mask and maybe go outside or work on a newspaper or a tray to collect the offcuts and dust.

You can either carve a design into them or push something into the soft bone. If you push, make sure you do it carefully so you don't snap it as I did! But as you can see, you can normally still use a different part of the cuttlefish. You'll need to carve a channel into the bone for your metal to be poured into and bind the two pieces of bone securely so the metal doesn't pour out the sides.

We didn't manage to film the pour... it was one of those days! You will find my sand casting video which shows how to make a channel and pour metal into it."

Kim - "Sand casting with delft clay with Kerry Day. Sand casting is usually done with a super fine sand which is impregnated with special oil to help it form around what you wish to cast and pick up all the little details. Here we are using a sand called delft clay. You pack it into a 2 part mold. Most sand casting molds are round rings and you have to be careful to match up both sides of your mold accurately.

My mold is rectangular and clips into itself which makes it very easy to align it but I haven't had much luck using it standing on end through the built-in channel recess. The molten metal often wouldn't fill the mold and you need to make air escape holes which in my mold, would also allow the metal to escape which is unsafe. We decided to use it the way the round ones work. So instead of standing it on end, we laid it flat and carved the channel and air holes on the top.

Make sure you are working in a safe area and are prepared in case of any spills. You can see my previous health and safety videos from Make It Month 12. You need more metal than your actual mold shape would require as you need enough metal weight to force it down into the mold before it cools. This means you normally need to use a powerful torch like my mapp gas, go system torch. The metal needs to be fully melted and combined so you can see me checking it with a soldering poker. Metal often looks molten but there are still hard unmolten parts inside. If you are doing this on your own, you can gently swirl your pan.."

Cuttlefish Casting Part 2 & Monthly Round Up

Finally, Kim shares a video on pouring molten silver into a cuttlefish mold - watch how well the cuttlefish holds up with multiple castings!

Meet the jewellers who love granulation...