OK, that’s a lie. This is a 3D printing themed longboard. The project started by wanting to do something artistic with the Open Source Hardware logo. I stumbled across the Prusa tattoo as I was researching the logo.
The tattoo is the OSHW logo with a simulated 3D printing hexagonal infill. The tattoo is fantastic looking, but I really did not want to just rip an existing design, even though I’ll bet it is open source.
I played with some ideas and thought it would look cool to make the lines look more like filament by giving them some height off the surface. I kicked around a lot of materials from paracord to thick wires, to actual 3mm filament. I finally decided to use rubber oring cord stock. It would be a low cost, practical material and also be durable with a nice feel under the feet. As I played with that, it hit me that I should switch concepts and make it look like the whole board was printed. The OSHW logo was a little complex to work in the new design, so I switched to the simpler reprap teardrop logo.
I start by loading some really ludicrously large values into Slic3r, like a 4mm nozzle diameter and giant work envelope. It actually did not mind and sliced the long board up like it was ready to print it. I snipped out one of the inner layers from the G-code and loaded it into a CAD program. I had to manually make a lot of changes for aesthetic and practical purposes. The oring was going to lay into a groove cut with a ball end mill. To look best, the number free ends needed to be reduced and I needed to add a reasonable bend radius to the corners. I really wanted to do a hex infill pattern, but there was just not enough space on the board to do a good job of it, especially around the logo. The logo was printed about 4mm thick in bright green ABS.
Here is the process I followed
- Cut the blank on aa CNC router out of 18mm baltic birch
- Pocketed holes for inserts for the truck mounting screws on the back (I did not want them to show on the top)
- Rounded the edges with a 1/4″ radius bit on a manual router table.
- Finished with several coats of water based semi gloss varnish.
- Cut a pocket for the printed logo using a 1/8″ bit.
- Cut the grooves for the oring with a 9/64 (0.141) ball end mill.
- Glued in the oring using super glue. For some areas I pretreated the oring with accelerator.
- Installed the oring.
- I normally use spare varnish for a job like this, but I had to do all the coating inside and had limited time. Oil based spare varnish cuts cleanly on the router. The water based stuff did not cut cleanly and needed about an hour of manual cleanup arfter.
- I would get a needle tip for the glue. A tiny bead down the center of the groove would have been best.
- It has an awesome feel under bare feet.