On Wednesday night, State Route 526 was temporarily closed to traffic to transport a very special, very large oven to Boeing’s Composite Wing Center in Everett.

The high-pressure oven, known as an autoclave, is there to “bake,” as the Seattle Times reports, the new 777X jet’s carbon fiber composite wings “to hardness.”

The Boeing Company provides more details:

This is the first of three autoclaves that will support 777X wing fabrication. It is 120 feet long, 28 feet wide and weighs 1.1 million pounds.

The autoclave was built and assembled adjacent to Paine Field in Everett, and is being transported to the Composite Wing Center, a new 1.3 million-square-foot facility under construction on the Boeing Everett site.

Keeping the 777X and its wing production here in Washington state was the focus of a special session back in November 2013, when legislators and the governor agreed on a package of aerospace incentives and investments. There has been some second-guessing of that package, but it’s hard to argue with its long-term economic and jobs benefits to our region.

The first autoclave now in place, Boeing enters a new design phase of the 777X project. Construction of the Composite Wing Center, begun less than a year ago, should be complete in May 2016. 777X production starts in 2017, and six customers have placed orders and commitments for 320 planes.

Here’s a photo of the autoclave:

And you can click here to watch on YouTube a time-lapse video of the autoclave being moved into the Composite Wing Center.