The National Museum of the Marine Corps in Triangle, Va., is building a new exhibit depicting a dramatic helicopter scene from the Vietnam War. Marine Sgt. Chasen Upshaw is one of eight life-size figures that will be cast in the museum piece. (Jorge Ribas/The Washington Post)

Marine Sgt. Chasen Upshaw is sitting in a swivel chair with his shirt off, learning the hand signals to use during the operation.

A “thumbs up” means the mission is on. If he waves his tattooed arms, it’s scrubbed. During the work, he won’t be able to see, speak, or even hear very well, because of the ear plugs. And he’ll have to hold that intense facial expression for about 20 minutes.

Upshaw, a machine gun instructor, cracks his knuckles.

“All set?” asks model sculptor Marc Dams.

“Ready to rock,” Upshaw says.

Upshaw, with plaster around his shoulders, is lending his visage to an ultra-realistic Vietnam War installation under construction at the National Museum of the Marine Corps in Triangle, Va. (Nikki Kahn/The Washington Post)

Dams, wearing blue surgical gloves and a white apron, begins to slather Upshaw’s face, head and neck in a thick, pinkish goo that drips down the sergeant’s chest. It covers Upshaw’s eyes, ears and nose, except for his nostrils, until he looks like a figure from a horror movie.

It is a little after 10 a.m. Thursday, and Upshaw is being immortalized for a dramatic new tableau at the National Museum of the Marine Corps in Triangle, Va.

A fiberglass model of him, depicting a young Marine in 1965, is being made for the life-size re-creation of a scene from the Vietnam War’s Operation Starlite, a bloody engagement that August, early in the conflict, that killed dozens of Marines and Viet Cong.

In the scene, a group of Marines and a Navy corpsman have just jumped from a helicopter hovering over a rice paddy and are dashing for cover in the midst of battle.

They are being depicted, as if in a photograph, frozen in full stride, with their weapons and gear.

The museum, obsessed with authenticity, has acquired the exact kind of helicopter in use at the time — the bulbous Sikorsky UH-34 — and is clothing and equipping Marines in period uniforms and accouterments.

For the 1965 fiberglass Marines, the exhibit’s creator wanted, as models, real Marines — right down to their tattoos, teeth and the wrinkles in their fingers.

Details, from the type of helicopter in use to the exact rifles that will be held by the figures, are crucial, museum officials said. (Nikki Kahn/The Washington Post)

So the museum this week has been bringing modern-day Marines to its exhibit fabrication shop on the base in Quantico, Va., to pose as their brothers in arms from a half-century ago.

The project is part of a major expansion of the museum, which will close in January for about three months as it adds new features and almost doubles in size.

Once the museum reopens April 1, the Vietnam exhibit will be installed in a large gallery near the entrance.

Upshaw’s is one of eight figures being cast for the scene. Most of the group had been photographed in their desired poses several weeks ago, with advice from Vietnam War veterans who had participated in such missions.

“We had veterans who had jumped out of helicopters, who had been in Vietnam,” Keith Bearley, the museum’s gallery manager, said Thursday. “They said, ‘This is what you’re thinking. This is what it feels like. This is what’s happening.’”

“You got the [helicopter] prop wash coming down on you, so you want to stay low,” Bearley said. “At the same time, it’s kicking up dust and dirt and stuff like that, so you’re trying to protect your eyes. But at the same time, people are shooting at you, so you’re trying to get to cover as fast as you can.”

“We want to give that sense of impending doom,” he said.

Museum specialists said they plan to create a simulated rice paddy and add props, such as scattered machine gun shell casings and ammunition crates. They also might add a simulated land-mine explosion.

Uniforms must be precise. “We have a spreadsheet of probably 150 different uniform pieces,” said exhibit specialist Alice Webb. The 1965 Marines’ gear was not necessarily all regulation.

Upshaw, who was portraying part of a machine gun team, had already had his legs molded in a running position and now was about to have the crucial head molding.

Sculptor Dams first smoothed petroleum jelly on Upshaw’s eyebrows and eyelashes so the molding goo — called alginate — would not stick when it cured.

Once preserved, the molding would be covered with cloth strips of plaster soaked in water, like those used in a cast for a broken bone. At that point, Upshaw would resemble an Egyptian mummy.

But before that, he needed a realistic facial expression, which would also be captured in the mold.

“Little more grimace with the mouth, I think,” Bearley said, as he aimed a camera at Upshaw. “The eyes are good.”

Upshaw had to remember: It’s 1965. It’s his first time in Vietnam. He’s a little scared. “People shooting at you,” Bearley prompted.

The sergeant grimaced some more.

“Yeah, yeah, yeah,” Bearley said. “There we go. Just bring [back] the corner . . . of the mouth a little bit. . . . Just hold that as long as you can.”

As the process began, it was relatively quiet in the room. Curtains were drawn across the windows. Containers of Krazy Glue, ear plugs and petroleum jelly sat on a nearby table with a pair of scissors and a jug of adhesive remover.

In the next room, casts of other Marines made on previous days were in pieces on the floor: Disembodied hands, arms and faces to be reassembled, painted and clothed.

The casts were so detailed that some of the Marines’ tattoos were faintly visible.

When the work is done, the models will be taken for fine tuning and the installation of glass eyes to Taylor Studios in Rantoul, Ill., where Dams and lead sculptor Shawn Hensley work making museum exhibits.

Upshaw, the son of a lumberjack, is from San Bernardino, Calif., and said he has been in the Marines for almost eight years.

He has numerous tattoos, including one on his chest featuring the names of his three children, Skyler, Katelyn and Chasen, and one on his left forearm depicting the World Trade Center towers in New York City.

He said it was “crazy” that this Vietnam war scene happened a half-century ago. “It doesn’t feel like it was 50 years ago,” he said.

As Dams and Hensley slathered on the alginate with their hands, Dams explained to Upshaw what he was doing: “Swipe down past your eyes. Down both sides of your nose. Across your mouth.”

“Hold that pose,” he said. “You doing okay?”

Upshaw signaled thumbs up.

After he was covered with a second, thicker layer of alginate, Hensley wheeled over a cart holding a large container of water and stacks of the plaster cloth strips. “We’re going to start bandages,” Dams said.

Once the plaster was on and dried with a hair dryer, the two sculptors began cutting the material off with a table knife.

When Upshaw emerged, blinking, bystanders cheered.

The mold bore an exact, negative image of his face — a life mask that when cast and installed in the museum next year will make him 25 forever.