See scenes from the foundry casting of Memorare, Sand Creek 1864

We promised a recent buyer of Memorare, Sand Creek 1864 that we would send updates of how his piece is progressing at the foundry. Then we thought, perhaps everyone might find this process to be of interest, so we are sharing the casting details with you.

Lost Wax Casting Method

Memorare, Sand Creek 1864, like all of my work, is being made with the lost wax casting method. This is an ancient practice that involves the following steps:

1. Mold: The foundry makes a mold that has a pliable latex interior and a solid plaster exterior. This is made by encasing my clay sculpture in the mold materials.
2. Wax pour: Hot wax is poured into the finished mold in thin coats until the desired thickness is achieved.
3. Wax removal: The mold is removed from the outside of the hardened wax.
4. Chasing: A heated metal tool is used, by hand,  to smooth out any seams or imperfections in the wax.
5. Spruing: The chased wax is affixed with “sprues,” which are branch-like paths on which the molten bronze will flow.
6. Slurry: The sprued wax is dipped in a silica/sand slurry that will harden into a shell-like mold, typically called a ceramic shell, although ceramics are not actually used.
7. Burnout: The ceramic shell with the wax inside is placed into a kilt to both harden the shell and melt out the wax. The foundry then has a perfect mold in which to pour the molten bronze.
8. Testing: The cooled ceramic shell is tested with water to check the venting and feeder tubes created by the sprues. Any defects in the mold are repaired.
9. Pouring: After the shell is finished, molten bronze is carefully poured into the shell. The shell is heated first so that the bronze does not cause it to shatter.
10. Release: Once the bronze has cooled, the shell is sand-blasted away and the now-bronze sprues are cut off.
11. Metal chasing: The bronze is carefully worked by hand to remove any air bubbles, rough edges, or other defects.
12. Patina: The finishing touch occurs when the patina artist, called a patineur, applies the finish of choice to the bronze.

Memorare‘s progress

As you can see by the list above, sculpture casting involves many steps by skilled craftspeople to get the bronze ready for display. For this current version of Memorare, the piece is now in the foundry’s shell room, where the ceramic mold receives several coats of slurry to strengthen it before it is kiln-fired.

Here is what has transpired thus far:

Wax pouring

Here is the mold filled with the poured wax.

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Wax removal

In this step, the wax of Memorare, Sand Creek 1864 is carefully removed from the mold.

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Wax chasing

Imperfections in the wax (such as seams and air bubbles) must be repaired by hand.

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Spruing

Wax extensions are affixed that will eventually be paths for the bronze to flow into the completed ceramic mold.

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Adding layers of slurry to the mold in the shell room

Once the layers of slurry have been completed over seven to 10 days, the ceramic mold will be fired the sprued wax melted off so that the mold can be readied for the molten bronze.

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Stay tuned for our next installment, when we reveal the newly-cast bronze.

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Are you interested in adding Memorare, Sand Creek 1864 to your collection? I am offering a limited number to private collectors. Please contact me for details.