FAQ: Life casting

Life casting is a fascinating (and fun!) process for both the client and the caster. Sculptor Julia Ambrose Murphy answers some of your most-asked questions.

How do you make a hand cast?


Life casting is actually a fairly simple process! First, a mold is made using a skin-contact safe rubber known as alginate...the same stuff used to make dental impressions. Depending on the pose, your hand will either be submerged in a bucket of alginate, or the alginate will be painted and poured over your hand, then have a supporting shell of plaster bandages applied over it. During this process, you must hold the pose until the material sets, usually in a few minutes.

Once the alginate has set, you must carefully remove your hand, usually with a lot of finger-wiggling so the mold doesn’t tear. This leaves a cavity in the exact shape of your hand, which is carefully filled with hydrocal, a high-density sculptor’s plaster. During this process, the mold is carefully rotated and tapped to discourage air bubbles, then allowed to set for several hours so the plaster can harden enough to safely open the mold.

Then, the most exciting part: the big reveal! The alginate mold is carefully cut away to expose the plaster cast, which has captured your hand down to the smallest detail. Fingernails, skin texture, and fingerprints are all reproduced exactly...this is why it is recommended that you trim your nails and remove your rings a few hours ahead of time: the indent from your ring will be faithfully reproduced as well!

The mold is usually destroyed during the process, so a single cast is produced. Multiple casts can be made by either repeating the process with alginate, or making a permanent mold from the first cast. Once the cast is free of the mold, it must then be carefully dried before finishing.

What is life casting like? Does it hurt?

Not at all! Alginate is a very safe substance made from algae, and is gentle on the skin. It will not stick to anything on its own, but might cling if it creates a mechanical lock, so a release agent such as baby oil or Vaseline is applied to the skin first to spare the fine hairs of your hand and arm.

Alginate begins as a powder and must be mixed with water in order to cure, and is also temperature-sensitive. This means that colder water makes it set up more slowly than warmer water, though the typical working temperatures are between 70-80 degrees F. When casting babies and children, the temperature is usually around 90 degrees F in order to speed the cure and make it more comfortable.

While the mold is setting up, it is important that the subject(s) not move in order to preserve the desired pose and avoid hitting the side of the molding container. Before mixing the alginate, when the clock begins ticking on the working time of the material, the subject(s) practice the pose and the caster arranges the casting setup at the most comfortable height and orientation. Once the setup is adjusted properly, the rubber is mixed and poured, the subject(s) assume the pose, and then carefully dip their hand(s) into the bucket. The alginate will take between 5-10 minutes to set up, and then the hand(s) are very carefully backed out, wiggling the fingers to break the natural suction. Any tiny bits of rubber left on the hands easily rinse off with water.

What kind of finish do you use on the plaster to get the antique look?

I use a combination of shellac, paint, pigments and waxes to achieve the rich, aged patina on my plaster sculptures. But first, it is critical that the plaster be completely dry, detailed, and properly sealed.

While the plaster is still wet, air bubbles are removed or filled, minor imperfections are corrected, and precision carving and grinding occurs. This is where the craft of the sculptor is most necessary, since many small factors come together to affect the whole. I carefully design my casts so that the hands are not awkwardly “cut off” but instead come to an end that is aesthetically pleasing and makes sense to the overall composition.

A counter-intuitive part of the process is the distressing, or spot-sanding, of the dry cast. Life casts can have a strange lifeless quality to them if not handled properly, so this step ensures that the piece will read as a fine art sculpture instead of a craft project. It is at this stage that I also sand off fingerprints. Because of the archival nature of the piece and the extreme level of detail that the casting reproduces, I consider this a prudent measure to protect my clients’ privacy.

Once the piece has been detailed, distressed, and dried completely, I seal the plaster with freshly mixed shellac. It then receives a paint coat, followed by a series of wax coats tinted with pigments to create a layered, antique finish which mimics the beautiful, rich patina that one might see on a plaster in a museum. The entire process is worked by hand with great care, and no two casts are the same.

© 2019 by Toolmark Studio. 

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