BROOKLINE – The last thing you expect to smell when walking through the woods on a warm spring afternoon is the acrid scent of burning soda. But, then again, this was the Andres Institute of Art, and you could be faced with just about anything.

On this particular day, artist Joseph Montroy had his cupola furnace racked up, getting ready to melt a considerable quantity of scrap metal.

The reason for all this volcanic activity was the iron melt workshop, where participants were invited to carve their own designs into tiles, which would then be introduced to a dose of boiling hot iron. The result was that each attendee would then have a unique souvenir to take home with them.

From the beginning, Montroy was clearly in control of the situation. He walked around his apparatus – a device resembling a chimney, about 8 feet high – as the audience stood back, cordoned off by a rope fence.

“What I have here is basically a whole bunch of scrap metal,” he said. “Old sinks, bathtubs and the like. We’re going to boil it all down in this cupola furnace. Basically, it’s a shrunk-down version of a blast furnace. Although it’s smaller, the proportions are pretty similar.”

As the device was cooking away, he made frequent trips via a ladder behind the chimney to introduce a layer of scrap metal, a layer of soda and a few sprinklings of powder from a coffee can.

“We use soda because it has a much higher burning temperature than raw coal,” he said. “The stuff in the coffee can is limestone. It removes the impurities in the iron.”

Since the apex of cast iron was in the middle of the 19th century, this is pretty much old-school technology. But it’s a technique that Montroy clearly embraces, his device being only augmented by modern blowers and propane burners.

“Back in the old days, they would have used wood, but that would take hours and hours to reach the right temperature,” he said.

The temperature in question is about 3,000 degrees – but that can cool off quickly.

“The heat quickly dissipates once it comes out of the well,” Montroy said. “Once it’s out of the furnace, it comes down to about between 2,800 and 2,400 degrees. You have to move pretty quickly to get it into the molds before it cools down too much. If the temperature drops below 2,400 degrees, it gets kind of syrupy, and it won’t pick up the details of the mold.”

Montroy is an old hand at this, having taken up bronze casting in his undergraduate days.

“I started out with bronze in 1996, and then moved into cast iron in 2006, when I was at the Rochester Institute of Technology,” he said. “There are similarities in the disciplines, but it’s a slightly different process, with a different kind of furnace.”

Dressed in a heavy apron and gloves and wearing a protective helmet, it was clear Montrose was taking no chances with safety.

“This can be potentially dangerous,” he said. “But, as long as everyone inside the danger zone is wearing appropriate safety gear, it’s fine. We just have to be super careful and in control throughout the whole operation.”

As he pointed this out, he also was pulling on a pair of devices that looked a lot like moon boots.

“These are spats,” he explained. “They keep any kind of spatter [from] hitting your feet. The whole idea is that, as long as you’re wearing this clothing, the metal will just peel off. Otherwise, you’re in trouble.”

As the crowd waited for the stove to heat up, John Weidman, co-founder and director of the institute, kept a watchful eye on the proceedings.

“We established the institute back in 1998 with Paul Andres, who owns the property,” he said. “We established a 501(c)(3) grant, and in turn, he puts money into the institute at symposium time, so that we can set that up. This entails getting artists from other parts of the world. We host four each year for three weeks, during which time they execute a sculpture. They also get the opportunity to learn new techniques, utilize new materials and learn about the community here in Brookline.”

One of the more interesting points about the Andres Institute of Art is how the sculptures seem to loom out of the woods at you. According to Weidman, this is entirely intentional.

“We work hard to place the sculptures so that they’re integrated into the wilderness,” he said. “We’re not interested in manicuring anything.”

The time had finally come. The furnace was up to full heat; Montroy was working the fire, and reassuring his pourers at the same time.

“It’ll be easy,” he said. “Just keep it slow and steady. If you feel any splatter or burning, tell your partner. Do not drop the ladle. Tell him you’re going to put it down, and then we’ll deal with whatever issues you might have.”

All very well and good. The team went through a dry run, just to make sure that everybody understood where they were supposed to be.

The tension was tangible. The furnace was boiling away, and Montroy was poking around, making sure to get a good clean flow. Pouring assistant Mike Dawson took a deep draft of water, and then went back and took his position across from assistant Adam Schepker.

Montroy opened up the well, and a torrent of white-hot iron poured out of the well and into the ladle. As soon as the vessel was filled, the two men walked deftly over to the waiting molds and began methodically pouring the molten iron into them. Working in a clockwise fashion, they filled up all of the molds with speed and alacrity.

After allowing the metal to cool off a bit, the molds were broken off and the finished casts were transported to a water bath, whereupon the excess was filed away.

As each of the participants gathered up their custom-made casts, they were left with a memento of a very special and informative spring day.

Eric Stanway can be reached at eric.stanway@yahoo.com.