Conserving the Terracotta Warriors with Glue

The first full Terracotta Warrior retained all of his vivid colours in 2004, just a year after boffins from the University of Munich discovered a way to stop the hues fading to grey- and it involves little more than a lick of superglue! The experts developed their breakthrough technique after discovering why the warriors‘ hues, which can range from blacks and browns to greens and purples, faded almost immediately after they are taken from the soil. “If you excavate them, they dry out instantly and in five minutes, the paint peels off,” the university’s Heinz Langhals told New Scientist. The problem results from the natural lacquer applied to beneath the fragile paint pigments. When the warriors are excavated, the dry air above the soil causes the lacquer to dry, peel off and take the paint with it.

To avoid the issue, scientists are now packing all newly-dug statues into special containers which match exactly the humidity of the soil. Then they are doused with the monomer hydroxyethylmethacrylate (or HEMA; try saying that out loud). The experts then flood the warriors with high energy electrons, which harden the HEMA, forming a glue which keeps the paint in place. HEMA, incidentally, is a common building block substance used to create many modern plastics. “Once they’re treated, you can handle them without any precaution,” claimed Langhals.

After the innovation, a Green Faced Warrior finally made his debut appearance in 2004.

Langhals and his colleague Daniela Bathelt finally realised their dream of salvaging the first fully coloured complete soldier just one year later, when a slightly less weary-looking infantryman made his debut at Beijing’s Millennium Art Museum. The 1.6m kneeling soldier has retained more of a fearsome look than his monochrome cohorts, with fiery eyes and a bright green face. The strange skin colour indicates he was supposed to be a non-Han fighter.

After the warrior‘s appearance, the museum’s deputy director bemoaned the overeagerness of former archaeologists at the famous mausoleum site, home to the First Emperor Qin Shi Huang. “The damage was caused partly because archaeologists cared more about how many sculptures were dredged up, than about preserving the coloured drawings on a warrior in the early phase of the excavation project on the mausoleum,” Wang Yudong told “As the project went on and international exchanges became frequent, people gradually realized the significance of protecting all the information attached to cultural relics in the mid-1990s.”

The warrior has since returned home to the city of Xi’an, the ancient capital of China. There’s much more to the ‘eighth wonder of the world’ than you may think – check out Heritage Key’s own top ten facts for some things you might not have known.