This post is a brief overview of how the magnetic Mendota Map for the Wisconsin Hoofers was built…
Here’s a link to my post about the completed project and the design choices that shaped it.
Reading through this summary, the procedure may seem straightforward… In practice, every step was a process of weighing the options, testing with scrap material, often attempting repeatedly to get it right, and second-guessing the choices afterward.
I had a lot of help putting this project together. I would especially like to recognize fellow Hoofers: Dennis Mossholder, who suggested all of the right materials, and Eric Oberhart, who did all of the text label design. Justin Randall helped with every aspect of the project, from power tools to emotional support. Finally, the Sector 67 workspace staff and members were instrumental in accomplishing the project.
Throughout the project, we used equipment at Sector 67 (www.sector67.org), a community workspace on the east side of Madison. For the cost of a monthly membership, I had access to a laser cutter, a full woodshop with 4-by-8-foot CNC router, and countless other tools, as well as guidance on how to use them.
The photos posted with This Union Reinvestment Blog Post (http://unionreinvestment.wisc.edu/?p=3046) offer a nice glance at how the software, tools, and people at Sector67 helped make this map possible.
Building a Model (October 2013)
We started by building full-sized cardboard model, cut out of single-ply cardboard using the Sector 67 laser cutter. Modeling the piece helped me grasp the idea of the map as a full-sized object. The model would later prove helpful in explaining what we were building.
In the early planning stages, I had a lot of help from fellow Hoofer and experienced craftsman Dennis Mossholder, who suggested several of the materials ultimately used in the map. He recommended Baltic Birch for the wood components and found a product called Magnetic Laminate (HPL#150) from the company Chemetal to create a surface which would attract magnets. It’s a laminate composed of an iron foil sandwiched between layers of a paper & resin material. Only 1 mm thick and lightweight, it attracts magnets like metal but can be cut using woodworking equipment. We laminated the Chemetal material to a backing of 3 mm Baltic Birch plywood using contact cement. The wood added support for the thin, floppy Chemetal laminate.
Cutting (November 2013)
I used data from the Wisconsin DNR to produce Mendota’s lake depth contours at 10 foot intervals. We used a 4 by 8 foot CNC router at Sector 67 to cut the stock material into layers of lake depth. One depth contour was cut from each layer of material.
For some video footage, check out:
Painting (January- February 2014)
After cutting out the map pieces, we needed more table space and fewer power tools, so the map moved to Memorial Union. We worked on it for months in the Hoofer boathouse, just down the hallway from its final home in the Chart Room. After the material was cut, I painted each layer. To achieve a blue gradient, I started with a base coat of paint in shades of grey, from white at the shallowest to nearly black at the deepest layer. I added a medium called absorbent ground to create a dry, chalky surface for the blue ink that I brushed on next.
Finishing (February – March 2014)
Finding a suitable clear-coat for this project was one of the greatest challenges. The finish had to hold up to touching and magnet movement, yet be thin enough not to impede magnetic attraction. I first tried an artists’ spray varnish, but soon found that it would stick to a magnet and crack away from the surface, removing the paint below. After several more hours of research, I chose to use a clear enamel top coat. The look of the enamel finish is great for this piece. It gives the lake area a candy-apple shine and retains some of the texture of the brush-strokes, adding visual interest.
Assembling the Lake (April 2014)
The base of the entire assembly is one large piece of half-inch-thick plywood, which we called the backboard. The backboard extends 3/4 in. past the edge of the Chemetal material on all sides. The lowest layers were inset into the wooden backboard; subsequent layers were stacked and secured down to the backboard using woodscrews. We had to grind off the pointed ends of screws where they protruded from the back of the piece.
Wooden Frame (April – May 2014)
Finally, we built up a wooden frame to enclose the piece, hiding the scrap material supports, screws, and dripping glue. We cut the wooden pieces on the CNC router, shaping them to fit the edge of the map, which wraps around the shape of the lake.
Installation (May 2014)
The map was mounted onto the wall using Monarch Metal’s Z-Clip hanging system. I estimate that the map weighs about 80 pounds.
The Complete Map (May 2014)
Finally, the complete map is on the wall!
The magnetic text labels were designed by fellow cartographer and Hoofer member Eric Oberhart. I added some Scuba dive flag magnets, and I hope to continue to create more… Maybe a 3-d printed capitol building? Maybe the street network? Other Hoofer members can also design magnets customize the map display.
Video of magnetic labels in action:
Dedication Plaque / Cabinet
The dedication plaque was installed next to the map on Aug 22, 2014. It doubles as a cabinet to store the map’s magnetic labels. I built the cabinet in about two days at Sector67, using a router, belt sander, laser cutter and mill.