Boynton Beach, FL #2Bethesda Hospital
Large Metal Sculpture
We (my intrepid assistant and I) fabricated a very large metal sculpture from aluminum and shipped it in October 2012 to the new Bethesda Hospital in Boynton Beach, Florida. I photographed each of the steps in the metal sculpture fabrication process and share 24 of the photos, with commentary, with you in this article.
A large metal sculpture is a great joy to make. A big sculpture is an exuberant celebration of the human spirit for me: the ability to imagine the design of the metal sculpture and to foresee it finished; to work out each step of the fabrication process in advance; to foresee possible and probable problems in the near and far future (including severe weather, vandalism, people climbing on the sculpture); to find quick and good solutions to each unforeseen obstacle as it arises; to maintain energy, strength and morale in the face of tight deadlines; to coordinate crating, shipping and installation; and of course, to manage all the relationships involved and get paid properly as well.
Please click on any image to enlarge – then click on the right side of the image to cycle through all 24 images with commentary.
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- All the aluminum is shaped and pairs are spaced, ready to get sides
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- Showing the 1/2″ square rod triangular bracing in the bottom half of the central figure – hope to withstand 80 mph winds when the next big wind hits
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- Another view of the triangle bracing inside the sculpture
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- Sides are on and tacked in place, ready for welding & grinding
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- Edges and seams are welded and welds are ground, fixed and finished. Ready to put the two parts together.
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- Aligned, strapped, drilled and ready to get pegged
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- Pegged with a 1/4″ aluminum 6061 rod – used a 12″ drill bit
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- Double pegged and welded and smoothed – that’s the look I like
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- The two parts are joined by double pegging and welding in three different places (but here at the top, too tight – couldn’t grind this bead – not visible from the ground though
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- Bottom of the center figure – ready for mounting plate
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- Trying to balance the big thing
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- First try – looks pretty good – but the plate is not positioned right – have to redo it
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- Ugly but it will work, the plate is in the right place and the sculpture stands on its own
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- Ready to add the sides to the mounting plate – the 1″ steel brace is to keep the aluminum from warping from welding heat
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- Sides on the mounting plate – I like the welds ground smooth for that ‘cast metal’ look
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- 5/8″ stainless thread rod, epoxied in place. The blue tape indicates how far to screw it in
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- Have to sign it
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- Note the drain holes in the two lowest points – without those, the sculpture would fill up with water in a few years
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- 12″ x 28″ diameter top base – have to bolt these together – welding heat warps the metal
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- Bottom base 36″ x 38″ diameter
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- Bottom flat plate on as well – all nuts are secured with epoxy and lock washer
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- All Assembled – side view – ready for the crate – no time to stand it up and get a proper photo
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- Ready for the sides on the crate – this is on a 16′ skid – shipping cost the client $2700!
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- Installed! – 15′ 4″ high
Metal Sculpture Fabrication Concerns
I was particularly worried about high winds torquing this metal sculpture. The two parts do reinforce each other structurally, but the bottom four feet is a large hollow square tube made of 1/8″ aluminum. Could that survive an 80-100 mph gale for 24-28 hours? This metal sculpture is designed for Florida, after all. I decided to reinforce the bottom 4′ of the metal sculpture with 1/2″ x 1/2″ solid aluminum rod, annealed to shape to conform to the insides of the sculpture and welded securely in place. That should do it. The 1/2″ square rod is aluminum 6061 alloy. It has the strange property, after being annealed and shaped, of time-hardening to its original very stiff temper.
The mounting plate was also an area of concern and it was reinforced with a square of 1/8″ aluminum seam-welded in place to the underside of the sculpture. The sides of the mounting structure were made with 1/4″ aluminum for extra strength.
Warpage is always a concern with aluminum. Thicker metal requires more heat to weld it, which causes more warping. Clamping the metal in place with 1″ steel bars helps, plus quick cooling. I usually bolt the metal sculpture to its various bases. Eight 5/8″ bolts is equivalent to one solid 5″ bolt. That should do the job.
Estimated time to completion for this large metal sculpture: About 200 hours.
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Wow – love the photo sequence. Thanks for all your great posts!