Horn Section

Commissioned by the City of Atlanta Bureau of Cultural Affairs, The Horn Section was installed at the end of 2009 in Cleopas Johnson Park in Atlanta. The park is named after an influential marching band teacher at Morris Brown College.

Horn Section by Zachary Coffin | Photo: Tom Meyers
Horn Section by Zachary Coffin | Photo: Tom Meyers
A view from the ground.
The top and bottom of this piece had to line up in a very specific way. We set the big pipe exactly level and used lasers, templates and measuring tapes to bring all the shapes into the right relation.
The jig on the floor that we used to build the base was also used as a drill template for the stone anchors, and then used to properly locate the stones on site.
Building the base jig. The layout of this was critical as everything was based on this triangle.
One of the interesting things in this process was to sit in front of a computer 6 months prior and to try to anticipate all the potential fabrication problems. How much room do you leave for the flex of the steel plate when it gets cut? Heavy steel is notoriously sloppy with huge variations in the quality. Say the operator of the CNC torch wants to catch happy hour and increases the heat and speed of the torch resulting in sloppy corners....well what if you make one of those corners a critical reference point?
Horn Section by Zachary Coffin
Horn Section by Zachary Coffin
Horn Section by Zachary Coffin
Horn Section by Zachary Coffin
Horn Section by Zachary Coffin
These are the pivots that the horns move on. This is for the horizontal axis and the weight rides on two balls that fit into the grooves. The grooves change in depth so that the horn comes seeks to rest to the same place every time. These parts were CNC carved from a piece of wear resistant stainless stee and cost a bunch.
We had a set of templates precision cut to mark and cut the large pipe. They ended up being a bit difficult to use because the big pipe is not perfectly round or exact in dimension. Plus you have to take the thickness of the template into account, which is fine, but if the pipe is slightly out of round, it throws all that precision out the window. In the end we had better luck with paper templates.
This shot shows the Uber Table, which we built in order to build this piece, hard at work.
The little notches visible on the flat template are some of the reference points that were part of the template.
This is a very early version of the Horn Section that I proposed for the Alabama Jazz Hall of fame in Birmingham back in 1997. It has a lot of the same elements of the final piece. Kind of a weird story that I will blog about eventually. My first brush with corruption in public art.
This stone weighs around 9 tons and anchors the back leg.
The stones came complements of Blue Sky Quarry in Eleberton, GA.
Installation took less than a day with about 7 hours on the big crane clock.
Setting the base stones in place was the first step, we placed them accurately using the same jig we used to build the work.
When designing the horn, we intentionally left large gaps between the shapes. This was mostly to create interesting shadows, but I also have theory that it will be les hospitable to pigeons. But looking at it installed, I don't think pigeons will ever be a problem.
When working with insanely massive objects, balance and awareness of gravity is key.
This detail shot shows the intricate pattern formed by the stainless. Interestingly there are only 12 unique pieces to make the horn.
The horns are three feet in diameter and about 11 feet to the pivot point.
Horn Section by Zachary Coffin | Photo: Tom Meyers
The first time that we assembled this piece, everything went together perfectly. This is the magic of CAD.
Thumbs up!
The shape of this stone caused it to move slightly when we removed the jig. Putting it into its right position was a minor battle. The shape of the rocks I work with seems more and more random as the precision of the metal increases.
Joel Rose was a great help on this project.
Horn Section by Zachary Coffin | Photo: Tom Meyers
At the left of the photo, you can see the limiter for the movement of the horn. We didn't want the horns to smack their holders or each other in high wind, so that shape was determined to limit this. It is actually a sandwich of thin stainless with polycarbonate in the middle. Polycarbonate is one of the toughest and most weather resistant plastics out there. Backing it on both sides with stainless should result in a system that lasts for decades.
Horn Section by Zachary Coffin | Photo: Tom Meyers
Here are the granite counterweights. They ended up beging smaller than I first anticipated as the horns ended up so light and strong. The advantage is that there is less mass to overcome to move them in the wind. I think it is interesting how a random cut of stone can so easily evoke a face. I am sure that it has more to do with the structure of our brain than anything else.
Jeffry Loy stepped right in and got to polishing the metal while it was still at ground level.
Presentation Mode On Presentation Mode Off