BOUND ONLY BY IMAGINATION (Part Two)

BUILDING A BETTER BACKYARD
As a second-generation metalworker, Kris Kesler is most comfortable on the factory floor. An expert TIG welder, he strolls around his 20,000 sq ft fabrication facility in Phoenix, AZ, with a welding mask permanently perched atop his head. As the co-owner/head artist at Bobé Fire & Water Features, one minute he?s tweaking the pounding rhythm of a metal stamping machine, the next he?s hunkered over a computer inputting new commands into a computer numeric control (CNC) plasma cutter.

Today, however, Kesler is literally miles away from his comfort zone. The ever-present welding mask is nowhere to be seen, although his wooly brown hair still shows signs of a permanent strap line. Instead, Kris is sitting around a patio table overlooking a verdant, grass-lined backyard that?s hidden behind a gated community inside one of Phoenix?s ritziest zip codes. Blocking the sun with his hand, he?s demonstrating to the homeowners the latest 3D models of their custom waterfall fireplace on his laptop computer.

Based on an earlier design named the ?Fire & Water Place,? the surface of this freestanding fireplace/fountain is completely covered in flowing water. However, for this particular job, Kesler has incorporated a new twist: twin sheets of glass-like water flowing in front of the double-sided fire window. Furthermore, each water feature is independently valved, so the clients can take advantage of the cooling water throughout the scorching summers, and then enjoy an unobstructed, warming glow when the weather turns cool.

Created with SolidWorks 3D CAD software, Kris? model is incredibly precise. Clients love it, he says, because it shows them exactly what they are getting and there are no surprises. Kesler, meanwhile, loves how 3D modeling makes his designs ?sub-contractor proof,? allowing him to ship his pieces anywhere in the world and know that the site has been prepped with gas, electrical, plumbing and a support structure to his exact specifications. Most important, the 3D model will serve as Kesler and his team?s step-by-step instructions for fabrication and assembly. So let?s back this train up and see how Kris goes from a simple sketch to a fully-engineered, fabrication ready design.

ELEMENTAL ENGINEERING
Although the mechanical and design engineering of waterfall fireplace is relatively complex, the building blocks are pretty basic, notes Kesler. ?I knew right away it would be propane gas powered, with full stainless steel ductwork, as well as an in-line blower to provide a steady air supply.? Further simplifying matters, Kris tried to incorporate as much existing engineering and mechanicals as possible, even on a custom piece such as this. ?I enjoy pushing boundaries, but there?s something to be said for time-tested and proven,? he adds, pointing to his use of external water pumps. ?It?s reliable and very easy to access in case of a mechanical breakdown.?

When starting any custom project, Kesler begins with the exteriors, locking in the specific shapes, materials and measurements, before tackling any interior or mechanical elements. Of course, any fabricator will tell you configuring the internal components to work around a set form can create complications. ?But I?ve learned how to design with enough wiggle room to make it all work,? explains Kesler. More critical, he emphasizes, is thinking ahead to the fabrication process. ?With every piece, I also need to determine how it will go through the cutting or pressing machines; what type of design will give me the best weld; and what type of filler rod will give me the best weld aesthetics for a variety of materials??

Which is when this traditionally-trained metalworker turns to a high-tech new toy?the aforementioned computer software. This next generation of CAD modeling allows Kelser to test the strength or the structure of individual parts, simulate the effectiveness of different construction techniques and even determine how well the completed project will hold up over time. Utilizing SolidWorks, Kris is able to run thousands of simulations to virtually test everything from tolerances and leak resistance, to the smoothness of the water flow and the height of the propane flames.

That said, this particular project did not require a lot of computer simulation, mostly due to the fact that the water is not falling a great distance. The real difficulty, notes Kesler, was ensuring an even water flow despite the cramped interior spaces. ?Usually we try to mirror the plumbing the same on both sides, but on this project most of the ductwork had to be squeezed in wherever we could fit it.? Also adding to the complexity was the fact that Kris prefers to use fully-welded stainless steel plumbing, meaning everything has to fit together perfectly the first time.

To achieve that seamless effect of water flowing up and over all sides of the fountain, water is pumped up from the bottom via an external pump. Inside the fountain itself, there are four inlets, two on each side; one going up and down each side of the fountain and one each to feed the independent sheets of water flowing across both sides of the fire window.

The water for the main trough is pumped up both sides, and fed through a baffle so that it slowly fills the space. Eventually the water bubbles up and out of the metal slats topping the trough, and then gravity takes over, forcing it to flow down all sides of the fountain. The other two inlets feed water into two sealed metal boxes running along both sides of the fountain that create the dual sheets of water flowing past the fire window. Here, the 1½-inch pipes force water past the adjustable valve and baffles to create two bubble-free, glass-like sheets.

With the water flow set, Kesler turned to his attention to the next conundrum, how to get fresh air in and remove hot air from, a fireplace completely covered in flowing water? ?The tricky part was that I wanted no venting on top of the fireplace,? he says. ?So the heat from the flames will have to be sucked out and around and vented far enough away from the fireplace that it won?t be noticeable to the user.? Ultimately he settled on piping the hot air some 50 ft away to a spot adjacent to the home?s HVAC unit, where the propane tank will also be stashed. ?It?s a basic vacuum system. The complication comes from knowing where to put it and how to manufacture it.?

Removing the air with a fan also created another complication for Kesler. ?I had to add air to keep a continuous pressure so the sheets of water over the fireplace don?t get blown out or sucked in.? After a few hours of digital doodling, Kesler settled on running a stainless steel vent up both sides to pipe hot air away. The slatted COR-TEN vent top feeds into two large stainless steel pipes on both sides. Air is pushed in one side and vented out the other via an inline fan that?s sealed inside a stainless steel housing unit to control noise.

Finally, Kris was ready to add some spark to this fire and water feature. Propane gas is also pumped in from the bottom, and fed into a stainless steel pipe pieced with a single row of machined holes. Lit via an automatic ignition system, the fire can be controlled with a handheld remote or even by programmed to run off a client?s wireless PDA or a household smart system. ?The goal is to have a uniform height of 8 in to 10 in for each flame,? states Kesler, ?with the flame source hidden behind a layer of decorative tumbled glass.? Dark-tinted glass, he points out, because, unlike natural gas, propane leaves behind a resin as it burns.

Back at the Bobé fabrication plant, Kesler is busy feeding the computer model into one of his CNC plasma cutters. The welding mask, meanwhile, is back in its usual spot atop his head. With a few more key strokes, the massive plasma cutters roar to life, slicing and dicing the 3-1/16 in stainless steel panels that will make up the exterior of the fountain. ?I?m really excited to see how this one comes together,? Kris says as he digs through a rack of filler rods, looking for just the right alloy.

Next month, our story concludes as Kesler moves into fabrication, where fittings are machined, and materials are cut using both CNC plasma and water jets. The piece is assembled with silicon bronze and stainless steel that is fully TIG welded. In this stage, the computer simulations prove purposeful as minimal product testing is needed to complete the finished piece.

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Bobé Water & Fire Features, 3101 N. 29th Avenue Phoenix, AZ 85017, 602-253-3494, Fax: 602-253-3496, www.bobescuppers.com.