Cuttlefish Casting

About: "Imagination is more important than knowledge" Im a compulsive maker, I make something everyday. I live in Cornwall England right at the bottom of the country as far west as you can go. A few miles away is S...

Heres a simple way to cast pewter, heres my way of casting, theres more info out there online aswell. This is an ancient technique that allows the casting of basic shapes without the cost of expensive mould materials.
Cuttlefish wash up on the shores all the time, all thats left when found on the beach is a white oval shape with a soft side and a hard bony side.
What you need:
A few cuttlefish( can be found at the beach or pet stores have them for Parrots!)
Small off cut of hardboard.
Leadfree pewter.
Blowtorch or small camping stove.

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Step 1: Make the Mould.

So get hold of a nice dry cuttlefish bone, if its damp it wont take a mould and the hot pewter will spit. Cut off one end of the cuttlefish bone with a hacksaw, so that you have a square end.
There are two ways to make the impression in the mould, you can carve away at the soft side with small files and nails or you can use a simple piece of jewellery you have around and push this into the soft side of the mould, so that when its removed it leaves an impression. (see photos)
Flatten the soft side of the bone with some sandpaper wrapped around a bock of wood. Then make the impression about half inch or so down from the top of the flat end of the cuttlefish, then with a file make the pouring sprue from the top of the mould. This is where the molten pewter will be poured in and when finished it gets cut off.
Take a small piece of hardboard that will fit over the back of the cuttlefish, this will become the back of the mould, rub this board lightly over the soft side of the bone so that it sits flat.
In the photo of the cuttlefish with the round shape, Im making a ring with a flat top so this mould has a sprue to pour into and a hole at the base for the metal to flow into another mould for the ring top. (but thats another story!)

Step 2: Clamp the Mould

File a groove in the top of the smooth side of the hardboard to match the one in the cuttlefish. Now place the smooth side of the hardboard onto the softside of the cuttlefish so that both slots line up, this is where the molten pewter will flow into the mould.
I use a couple of metal clamps to hold the mould together, but soft wire can be used aswell, make sure the two surfaces of the mould fit well together or liquid pewter will escape during pouring.

Step 3: Melt the Pewter

Support the mould upright with the pouring slot at the top, make sure its on a heatproof surface. A couple of blocks of wood or bricks will stop it from falling over.
A few warnings at this point, wear leather gloves and a pair of goggles or a face mask to protect against burns, if the mould isnt quite dry it may spit back hot metal. Also any gaps around the joint in the mould will allow hot pewter to run out, so theres an obvious fire risk, also protect your skin from burns and you might like to have a fire extinguisher handy.
Melt a small amount of pewter in your spoon or whatever you want to use thats heatproof and pour slowly into the slot in the mould, which will fill quite quickly, stop when pewter is seen at the top of the slot.
Let things cool for about ten minutes or so and then carefully open up the mould and pick out the piece with a small file. You will get marks on the surface of the pewter from the cuttlefish but these can be polished out. You should be able to get a few casts out of each mould if you repair the surface after each casting. Which is fine because the cuttlefish are cheap (or free)
Cut off the sprue with a hacksaw and then file off any marks and polish with a dremel or polishing wheel.

Step 4: A Few Pewter Pieces

Heres some photos of pieces of pewter jewellery that can be made, Ive made these with a combination of cuttlefish moulds and hardboard. Have fun with it, watch out for hot metal and let me know if you have any problems with the casting.

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    24 Discussions


    7 years ago on Introduction

    Nice use of available materials. As Raised said, we don't have them wash up on this side of the Atlantic (at least not in my area), so the only source would be pet stores. Have you ever tried plaster or resin to see if that would work as a mold?

    7 replies

    Thanks for the reply webman,
    I have tried plaster of paris and auto body filler(bondo) which do work and stand up to the heat well. I still use a few two part moulds for jewellery, so I will do a structable soon. The other thing I have tried is silicone sealant, that comes in tubes for sealing around showers & sinks, it works but its a bit tricky to use.


    Reply 4 years ago on Introduction

    Try this Instructible:

    Use white spirit to dissolve the silicone sealant, and then mix in cornflower for stiffening. Look for the instructables on this, the amount of cornflower can give anything from a very flexible mould to a very still matrix.


    Reply 7 years ago on Introduction

    And as a small safety issue I would cast over a tray of dry sand so any spills will not splash over you.


    Reply 7 years ago on Introduction

    Some years ago I tried aluminum casting and tried using plaster of paris as a mould. I was unable to get my aluminum hot enough to flow so I melted the metal directly in the mould and when it got soft enough it conformed to the shape of the mould. The problem I had with plaster of paris is it didn't take the heat well and just by itself would crumble and break. I reinforced it with metal wire i had around here. It worked but I'd try something else first. I am wondering about using the type of cement used in kilns to make the mould. When the weather gets warmer I will be using charcoal blocks to do some casting. I think this should work as I have used them to cast gold some years ago. I"d love to find a way to make my own charcoal blocks as they can be a bit pricey when bought. You can find them under Charcoal Soldering Blocks in jewelry supply catalogs or web sites.

    I get leadfree off the web, in the uk a company called Tiranti sell it. Best to shop around on the web as the price does vary a lot. For small casting you can use leadfree plumbers solder from the hardware store. This has a high tin content, hope that helps.

    I've found dented pewter mugs at the thrift store for dirt cheap sometime. Like $1-2 for a scratched up tankard with a clear window at the bottom. These weigh about 5 oz each.

    To compare, I can get a 16 oz bar shipped to my door for about $17.49 if I spend $100 from

    The key is to make sure it says "pewter". if not, it's probably zinc. There are a few other tests, but this one will let you sort 99% of the stuff you find.


    Reply 4 years ago on Introduction

    Be careful with this, old pewter has a high lead content. The banning of lead was very recent, mostly in the 1970s for food and drink implements, anything predating that should NOT be used in this way.


    5 years ago on Step 4

    What type of torch did you use? Can a butane torch work for this project? Thanks!


    6 years ago on Introduction

    Do you do anything to darken the backgrounds (such as on the bracelet example in Step 4)? Or is that just unpolished pewter? It looks like a wash of black paint in the recesses.

    1 reply

    Hi Webman, sorry to take so long to get back,
    yes I do sometimes use black acrylic paint to darken the dimples in pieces, if you put it on before you polish the piece it will stay in the dimple, but the raised bit will shine up.
    Hope that helps
    heres a link to some work on Deviantart;


    7 years ago on Introduction

    Finally a use for those things. If only the pewter washed up as well!