PAWTUCKET, R.I. - Welding isn't just for aircraft carriers anymore.
The U.S. Navy could be turning to ultrasonic welding to make its uniforms lighter, stronger and cheaper. And if the project by a Rhode Island company and the Navy Clothing and Textile Research Facility is a success, it could help bring manufacturing back from overseas.
Welded seams - created when two pieces of fabric are essentially melted together by sound waves - are already used in some clothing that some Americans have in their closets. Patagonia and North Face both sell models of jackets with welded seams. But so far, most, if not all, of that manufacturing is done overseas.
Propel LLC is trying to figure out how to make one of the Navy's more expensive and challenging garments to assemble - the Navy parka, which it buys for $190.50 each - without stitches. It has spent the past year testing welded seams, adhesive techniques and other bonds using a federal grant from the Navy.
"This was a good way for us to start to get an understanding of what the current state of the art is," said Cleveland Heath, the technical program manager at the Navy facility in Natick, Massachusetts.
Current garment assembly methods can be cumbersome and costly, Heath said. Different kinds of stitches are used and garments have to be moved from sewing machine to sewing machine as they are formed. One welded seam could replace several stitch types and the sewing machines associated with them, he said.
The seam is a garment's weak point, said Propel president Clare King. Using a needle and thread creates tiny holes that air and water can permeate, taping a seam to cover the holes adds weight.
The welded seams have proven to be lightweight, flexible and waterproof, King said.
"We have a lot of opportunity to improve the garments and also effect change at the factory level," King said. "Some of these technologies have been used in factories overseas but we have no knowledge base here of how to do them or how to implement them."
Seams are welded on some large tents, liners and other specialty industrial fabrics, but not on typical, casual clothing. For the Navy project, King consulted Patagonia, whose M10 jacket has welded seams and is made in Vietnam.
Joe Vernachio, a vice president at The North Face, said he knows of only four or five factories overseas that weld seams for apparel. The military is required by law to manufacture all uniforms in the United States. Military uniform sales totaled $1.76 billion in fiscal 2014, according to the Defense Logistics Agency. The agency purchased nearly 44,000 Navy working uniform parkas that year.
Seams that are welded are typically straight lines, not ones that turn corners, and it's expensive to use this method, Vernachio added.
Few garment manufacturers are welding seams now, mainly because the easiest and cheapest way to make an article of clothing is still by sewing it, said Augustine Tantillo, president of the National Council of Textile Organizations. It has been too daunting to try to develop a machine at a low cost that performs as well as a skilled sewer, he added.
But if the technology could be developed and perfected for the military, it could seep over into the commercial market, Tantillo said.
There is precedent for such spillover: A synthetic alternative to goose down that was developed for the U.S. Army, PrimaLoft, is now widely used in outwear and bedding.
Finding ways to bring more manufacturing back to the U.S. is appealing to many retailers because the turnaround time is quicker when fashion trends change, and many consumers prefer goods made in America, said Harold Sirkin, a manufacturing expert at the Boston Consulting Group.
He believes they'd order more if the prices were competitive with markets overseas where workers are paid far less, especially now that labor costs are rising in Asia and oil and transportation costs are high.
Sirkin and Tantillo were intrigued by the Navy project and the potential it holds.
"If this technology works for them, it will probably work in other parts of the cut and sew business," Sirkin said. "It's far from proven, but if it works, it may change things."
Heath, of the Navy's research facility, said it's too soon to say whether Navy sailors will wear welded clothes one day. But, he said, it's important for the Navy to save taxpayer dollars and these technologies could do that.
"We're encouraged by the prospects of introducing a welded-seamed garment to the Navy and potentially offering this technology to other military services, with the added benefit of fortifying the U.S. industrial base," he said.
The next step for Propel is to apply for another grant to continue its research and test the durability of the seams in the field, King said.
King said the work is "tremendously exciting," especially because there are other technologies in development to assemble clothes in new ways.
"I strongly believe this is just the beginning," she said.