The Gibran Sculpture Series

In the last post, you saw the castings being poured.  There’s something really quite primeval about the process I feel, with intense, raw heat and red hot molten metal.  Anyway, once the whole thing has cooled, the castings, still in their moulds are removed from the casting box.  If the castings were coarse and with a crude finish, they would simply be ‘knocked out’ of their crude sand moulds, but these are fine art castings and the surface is all important.
So, now they are cool, the castings are removed from the box in their moulds.  The plaster moulds are carefully knocked off the castings by hand.  So the castings, at this stage, end up looking like this…

The cooled castings, having had their moulds removed and awaiting fettling.

Speak to us of Freedom – knockout

Knockout has nothing to do with boxing!  It is the term given to the process of removing, or knocking out, the castings from their moulds.  The photo above shows the individual castings having had the moulds removed.  They still have their runners and risers, sprues and followers (all the extra bits needed inside the mould to make the metal flow) still attached though.  (These are the bits that look a bit like tree roots).  The next stage is to ‘fettle’ these unwanted bits of bronze off, leaving just the raw castings, albeit with some little bits of mould still attached.

The final cleaning in the sand-blaster to remove all the last traces of mould.

You will no doubt recognise this as the same casting from the top of the post, but now looking perfectly clean and ready for assembly.

Personally, I find this completely fascinating and it’s something that very few people ever see.  I have prepared another post with more photos here if you are interested.

The next step is to start assembling the individual castings.

See the finished Speak to us of Freedom sculpture here.

To learn more about Kahlil Gibran, click here.

To learn more about Gibran’s The Prophet, click here.

The Gibran Sculpture Series

So once the wax has been melted out from inside the moulds (that’s why it’s sometimes called the ‘Lost Wax’ process), the empty moulds need to be made ready for casting.  These moulds are tall and thin and although they will stand up on their own, they are far too unstable to stay upright reliably while being filled with molten bronze.
So, the next step is to make them stay upright and here they are being put into a container to make sure they do.
The gaps between them in the container are filled with sand, which keeps them separate from one another and then they stay absolutely still throughout the casting process.

Preparing the empty moulds for casting.
The bronze is being melted in the furnace behind.
On the floor in front of the furnace is the special cradle that will be used to pour the metal.

Finally, after all that preparation, the bronze is poured into the moulds!

This is the moment of casting.  The crucible holding the molten metal is carried by two men using a special cradle with very long arms.  A third man directs operations and makes sure that the metal going into the moulds is free from any impurities.

The next step is to let the castings cool, which takes days rather than hours.

See the finished Speak to us of Freedom sculpture here.

The Gibran Sculpture Series

Oh my goodness, making a bronze work of art is such a time-consuming and detailed process!  It involves so many specialist craftsmen.

The Investment Process

In the last post, you saw the molten wax going into the silicone mould.  When the wax had hardened, it was carefully cut into sections and those sections are used to make the moulds.  This time though, the moulds are for the bronze. The wax is covered in lots of coats of a very thin, fine, clay-like mixture.

This produces a series of apparently unconnected bits which look very unlikely!  It’s done this way because the clay-like moulds record really fine detail.

So here they are, upside down and full of wax, waiting to go into the kiln…

Sections of wax, coated in ‘investment’ material.

So the next step is to ’empty’ the hard shells to create space for the bronze to flow in.  Here they are (below), having been positioned in the oven.

Mould sections in the kiln, waiting to be fired.

Next the oven is brought up to temperature, melting the wax which flows out.  What’s left is a lot of empty ‘shells’.  Then the shells are baked until they are really hard and can withstand molten bronze.

Speak to us of Freedom – the finished moulds

Here are the finished moulds.  These shells are perfect replicas of sections of the original sculpture.  At the bottom of the picture you can see something dark green.  That’s wax which has been melted out previously.  The metal buckets are used to catch any surplus that runs out of the front.

See the finished Speak to us of Freedom sculpture here.

The next post will show the actual casting process.

The Gibran Sculpture Series

We’ve moved on to the next stage in making the large (2.2m) Speak to us of Freedom sculpture.

The mould that was made of the enlarged model has been delivered to the Talos Art Foundry. The foundry is near Andover in Hampshire and specialises in casting bronze sculpture.  Now the long and complex process of taking a mould to a finished bronze begins.

The mould has arrived at the foundry and here it is being taken apart to be ready for the next stage.

The mould is in sections and the first stage is painting wax into each of the sections.  In the pictures, you can see how thick the wax is and that will be the thickness of the final bronze.

Making sure the metal flows!

Runners and risers are added to each section of the pattern.  These make sure that the molten metal runs into every nook and cranny of the mould.  As the molten metal flows into the mould, it solidifies very quickly.  If the space it’s going into is thin, it cools even more quickly and that often means that it won’t fill the mould.  So, these ‘internal pipes’  make sure that the metal runs down to the bottom of every bit and runs up to the top of every bit.  Without them, air will get trapped in the mould and there will be bits missing from the finished casting.

Here is one section of the mould being painted with molten wax.  The wax is exactly where the bronze will end up!

So here is the end of the first step.  The bottom 600mm section of the casting has been formed out of wax.  The circular rods are braces to hold the wax sections in place.

We’ll show you the various steps as we go along, so follow the blog and you can follow the process!

See the finished Speak to us of Freedom sculpture here.

The Gibran Sculpture Series

Today, two days before Christmas, we’ve completed the silicone rubber mould, backed up with fibreglass resin and delivered it to the Talos Art Foundry, near Andover, in Hampshire in the UK.

Work will start immediately on the next stage.  The foundry will begin by using the mould to make a hollow wax replica of the original clay model.

The finished mould on a trolley awaiting loading.

The mould loaded and ready for transport.  Note the Dove of Peace mould is separate from the main mould.  It will be cast separately and then welded to the main sculpture.

See the finished Speak to us of Freedom sculpture here.

The Gibran Sculpture Series