Deltech Furnaces

By Eric Peterson | Dec 05, 2022

Company Details


Denver, Colorado



Ownership Type





Industrial furnaces

Co-owner Mary Stevenson sees potential for her company's innovative furnaces in the global market for materials research.

Portrait courtesy Deltech Furnaces; other photos by Jonathan Castner

Calvin Stevenson, Mary's late husband, co-founded Deltech Furnaces with Don Drinkwater in the late 1960s as a consulting firm targeting the mining industry.

"Shortly afterwards, mining crashed, as it has been known to do, and they had to shift gears," says Mary.

Deltech gained traction when CoorsTek (then Coors Porcelain) called in search of a furnace. The company transitioned into furnace manufacturing in the early 1970s, since serving a market largely composed of researchers, materials scientists, ceramic engineers, glass manufacturers, national labs, and federal agencies. "They're mostly related to materials, and most of those are ceramics and glass," says Mary, who runs Deltech today with her son and business partner, J.J. Stevenson.

Over the years, standout projects have included a vertical tube furnace for NASA for use in lunar rock research; a large furnace to prepare glass for a telescope for the Jet Propulsion Laboratory; and a positive pressure furnace for the National High Magnetic Field Laboratory.

"More and more, we do custom projects, and they're often projects other people won't take on," says Mary. "It's one of the things that keeps the business interesting for our engineers. There's always something new, always a challenge."

She adds, "It was my late husband's philosophy that we listen to customers, talk to customers, and design and build the furnace that best fit their process. He called it, 'We build the furnace to fit your needs,' and we've stayed with that philosophy all these years. We don't want people to make do with our products, we want them to have a product that really performs optimally for whatever they're trying to do, whether it's research or manufacturing."

For manufacturing, Deltech handles the wiring and assembly in-house at its 5,500-square-foot facility on the northern end of Denver while relying on a largely domestic supply chain.

"We actually manufacture the furnaces, except for the metal frames, from the ground up," says Mary. "We outsource our weldments -- that would be the furnace frames -- and we outsource the powder-coated control cabinets in the colors we want. In terms of the vendors in general, they are really good knowledge resources."

Growth has ebbed and flowed over the course of the company's 50-plus-year history. "We're in a niche market, so things go up and down," says Mary. "A lot of times, what kind of money the government is spending on what makes a huge impact on our business."

Things have been mostly up in 2022. "This year has been our best year ever," says Mary. "We have almost doubled our average sales from previous years. I think this is one of those outliers, but we'll enjoy it while it's here."

Challenges: Supply chain and hiring. "Those are certainly two of them," says Mary. "We can't get away from that." Insulation, temperature controllers, and electronic actuators have been among the most difficult components to source, she adds.

Opportunities: Foreign markets. Labeling Deltech "an accidental exporter," Mary estimates exports will account for about 20 percent of total sales in 2022. "Our exports have grown, and we're waiting to see if we want to push for that," she says. "We're trying to take it more seriously and get some representatives if that's appropriate. I'm taking the World Trade Center's export accelerator training program."

The nuclear industry is another opportunity. A spinoff company, Deltech Kiln and Furnace Design, "is focused strictly on design and aimed at energy communities in general, but especially nuclear," says Mary. "The nuclear customers are the same as other customers -- they're doing materials research."

Needs: A bigger facility. The target is 10,000 square feet. "We've been hunting, and believe me, there's just nothing out there unless you want to lease," says Mary. "We've had customers visit us and marvel at the fact that we're able to do some of the projects we do in the space that we have."

A recent custom project, a 35-foot tunnel kiln for a customer in Australia, "presented some challenges, as you might imagine, with our small space," says Mary. "We ended up leasing some space from a customer of ours to do the assembly to the point of a test of the mechanism."

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