TEXAS CITY — The 11-foot, 8,400-pound Dahlgren gun now on display at the Texas City Museum spent more than 150 years under the murky waters of Galveston Bay.
The powerful gun once sat on the USS Westfield. But after so many years underwater, the gun needed to undergo careful conservation work before it could be put on display.
The 9-inch Dahlgren gun was brought to the Texas A&M Conservation Research Laboratory in the fall of 2009, said Andrew Thomson, lead conservator with Texas A&M University.
The first step in the conservation process was to use hammers and chisels to remove the sand, mud, shell and other debris that attached to the gun after years of being under water. Once the debris was removed, the gun was put through a process called electrolytic reduction. The artifact was placed in an electrolyte solution inside a metal tank. The tank is hooked to a positive charge, while the gun was hooked to a negative charge, Thompson said.
The electrical charge further breaks up any debris and also breaks down the salts inside the gun.
“That’s really what took the most time,” he said.
The gun spent about three years in the electrolytic reduction process, he said.
Once that was done, the gun was placed in boiling purified water to remove any salt and electrolytes present, he said.
The gun was then tested repeatedly until the salt and electrolyte levels were low enough that it could be coated in tannic acid and other rust preventive solutions to keep the service from corroding, Thomson said.
The final layer of protection was for the gun to be coated with black paint, he said.
“It’s presentable and it also seals any pores,” Thomson said.
After all the preservation work, Thomson said it was nice to see the Dahlgren gun in the museum.