US Mint Artists at Philadelphia Sculpt Digitally and in Clay

by Mike Unser on September 6, 2013 · 0 comments

This third article about our visit to the U.S. Mint at Philadelphia offers behind-the-scene information and photos about the artistic design process in minting coins and medals.

If you could, would you sculpt using clay or a computer? United States Mint artists at Philadelphia have their choice, with some switching between the two mediums.

Philadelphia Mint Artists and Plaster Models

It’s fascinating to watch gifted artists breathe life into models. The folks at the Philadelphia Mint have been doing a lot of that lately, more than any other year, with 83 designs already sculpted for coins and medals released in 2013.

It was a joy visiting with U.S. Mint sculptor-engravers Don Everhart, Michael Gaudioso, Joe Menna and Phebe Hemphill. They’re among the group of artists who take sketches and shape them into the models that are used to produce master hubs, master dies and working dies for striking coinage and medals.

When we visited the Mint last month, the artistic team was in high gear creating sculptures for a variety of upcoming releases. That gave us an opportunity to see the traditional approach to sculpting with clay and plaster and watch newer methods of sculpting with a stylus and computer.

Traditional Sculpturing

In traditional sculpturing, an artist with special tools captures the essence of a sketch in clay.

US Mint artist Michael Gaudioso

US Mint artist Michael Gaudioso, Medallic Sculptor. Mike, who studied sculpture in Philadelphia, New York, and St. Petersburg, Russia, uses clay on a Ren basin to bring a design to life. When finished, the clay model will be captured in plaster. The final model will be scanned and reduced to actual medal size.

We snuck behind Michael Gaudioso as he was using clay on a Ren basin to bring his Code Talker Congressional Gold Medal design to life. Ren basins are circular, have depth and act as a working foundation or template for sculpting.

RenShape model

Digital Process & Development Division. A prototype RenShape model is placed into the Mikron CNC milling machine. CNC milling machines not only cut hubs and 3” dies, but they also cut template models for artists who sculpt traditionally with clay.

Created by a CNC milling machine to the specifications needed for the final coin or medal, Ren basin’s already have common design elements such as mottos and dates.

Mikron CNC milling machine

Digital Process & Development Division. Mikron CNC milling machines are used to cut hubs, 3" dies, and Ren templates using digital information from the scanner or digital artist. It generally takes 15-20 hours to cut a coinage hub; 25-30 hours to cut a 3" die. These CNC machines are more efficient and can produce a better quality product than the retired Janvier Transfer Engraving Machines.

Artists take over from there, adding layers of clay as they sculpt the design on top and within the rim of the Ren template.

US Mint artist Michael Gaudioso sculpting

Gaudioso sculpting his Code Talker Congressional Gold Medal.

Mike showed us a nifty sculpting technique using a transparent overlay. It has a tracing of the sketch, and it’s taped to the top of the Ren basin. As a visual aide, Gaudioso flips the transparency up and down as he shapes the clay to a medal design in 3D.

US Mint artist Michael Gaudioso sculpting with transparency

Here, Gaudioso lifts the transparency to make refinements to the clay model.

The resulting clay model is then captured in plaster where additional refinements are made.

Digital Scanning of Plaster Models

Final plaster models are digitally scanned and reduced to the actual coin or medal size. This process is completed with a high resolution scanner. Section by section, it digitally maps the hills and valleys of a plaster model with a sensitivity that can pick up finger prints. The millions of mapped data points are sent to digital design software for modifications and then to a CNC milling machine to cut the steel hubs and dies for production.

high resolution scanner

Capture 3D non-contact, high resolution scanner used in Digital Process & Development Division. This scanner captures relief information from artists’ models, galvanos, tooling and coins. The digital information is then sent to the digital design software for changes.


high resolution scanner (b)

Another view of the high resolution scanner as it maps data points on a plaster model.


Stephen C. Antonucci (a)

Digital Process & Development Branch Manager, Stephen C. Antonucci, describes how the scanner captures relief information from artists’ models, galvanos, tooling and coins. Following processing, the scanned digital information is sent to the Mikron CNC milling machine which cuts hubs and 3″ dies.


Stephen C. Antonucci (b)

Antonucci describing the quality of detail on a high resolution scan of a coin model.

Sculpturing Digitally

Digital sculpting requires the same mental artistry as the traditional method, but models take shape within computer software instead of on clay.

Joe Menna was the first full-time digitally skilled artist hired by the U.S. Mint, and was instrumental in making the Mint a world leader in digital coin design and development.

US Mint artist Joe Menna

US Mint artist Joe Menna, Medallic Sculptor talking about the team environment at the Philadelphia Mint.

Joe’s mastery over digital sculpturing is something to behold. We were a bit shocked to watch Joe sculpt digitally since we rely on imaging software ourselves for coin effects. Our use is at a kindergarten level compared to Menna’s seasoned approach. With stylus in hand, he demonstrated layering and showed how quick changes can be made to a digital model. While working, Joe discussed the team culture at the Mint, talking about designer initials on coins and how they don’t show the many hands needed to produce coinage.

US Mint artist Joe Menna (a)

Pictured here, Joe uses digital software to sculpt the Franklin D. Roosevelt Presidential Dollar coin design.


US Mint artist Joe Menna (b)

Here, Joe shows how quick changes can be made to digital models.

An advantage in digital sculpturing is its time-savings. It bypasses the traditional clay to plaster method, adds the ability to make later design refinements without having to redo time-consuming steps, and it skips the high resolution scanning stage.

Mixing Traditional with Digital Sculpturing

Phebe Hemphill sculpts traditionally but will also use computer software to later refine her models. This mixing of the methods cuts turnaround times.

US Mint artist Phebe Hemphill (b)

US Mint artist Phebe Hemphill, Medallic Sculptor. Phebe is a graduate of the Pennsylvania Academy of the Fine Arts; she also worked as a sculptor at the Franklin Mint for 15 years. Here, Phebe inspects a plaster model.

As we watched, Phebe demonstrated the use of another software program, called ZBrush. Using it, she refined her 2014 Shenandoah National Park Quarter design.

All the Mint artists we talked to were exceptionally dedicated. No better example, Phebe hiked to Little Stony Man where she took the photos she used to create her quarter design.

US Mint artist Phebe Hemphill

Here, Phebe is using ZBrush, a sculpting software program, to modify her America the Beautiful quarter design.


US Mint artist Phebe Hemphill (a)

Another view of Phebe using the ZBrush software.

Common to Both Methods

Completed models, whether in plaster or digital, are always reviewed for errors such as misaligned letters, incorrect or missing design elements and manufacturability.

Eric Custer, Product Design Specialist (c)

Eric Custer, Product Design Specialist. He works in the Digital Process & Development Division. Eric has several plaster models that have been inspected.

When they are approved, the scanned or digital data is sent to the Mikron CNC milling machine to mill a blank piece of steel into hubs and dies that are used to strike the coins or medals.

Next Article in Series About the Philadelphia Mint

Stay tuned to CoinNews.net for more articles and photos about the Philadelphia Mint. The next article is scheduled for Friday, September 13. It describes the next stage to produce coins, creating master hubs, master dies and working dies from rods of steel. Other upcoming articles will show how circulation coins are minted and the making of bullion and collectible America the Beautiful Five Ounce Silver Coins.

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