Keeping with my interest in reusing old materials for new projects, when my dad asked me if I wanted a set of speakers from a 1966 Mustang he was restoring, I couldn’t turn down the opportunity. At the time I already had plans to make speakers for my desk, so I got to work right away. The 3D modelling for this “Nautilus Shell” style casing was done by a user on Thingiverse, which allowed me to focus a lot more on the fit and finish of these speakers. So far these have thoroughly surpassed my expectations, offering shockingly good sound for only the cost of my time invested into the project.
Between the two matching speakers, there had to be a total of 10 printed sections, as I had to split the shell into segments to fit within the build volume of my printer. This project offered me an excuse to finally experiment with larger nozzles (0.6 and 0.8 mm dia.) due to the large volume of the parts being printed.
As with the rest of my projects involving 3D printing, the components were printed on my customized Creality CR-10. With its 200x200x300mm build volume most projects can be printed in one piece. Of course this project managed to exceed those dimensions considerably, which added a nice degree of complexity to the assembly and finishing of the shells themselves.
The shell components were first bonded to each other with JB Weld, ensuring both a mechanically stable and acoustically impervious joint. Any excess JB Weld that oozed out onto the shell’s surface was cut back before it fully set, preventing the bonded areas from being noticeable after paint.
Initially, larger gaps and surface inconsistencies were filled with leftover JB Weld. Of course at this stage, the layer lines from the printing process were still present.
Both completed shells were drop tested once bonded together, ensuring that not only that the JB Weld was sufficient but also that the wall of the 3D printed shell were thick enough.
Bondo was used to clean up the layer lines and any other surface inconsistencies. This is significantly easier than sanding the PLA shell on its own would be, and does not require printing extra thick walls to make up for material sanded away.
The shells were coated in a standard flat grey base coat to ensure the top coats would properly adhere regardless of the shell’s material. The base coat also acted as an additional filler to smooth out scratches and unevenness in the finish.
Next came the top coats of paint, which was one of the largest focuses of the project. I specifically chose a “textured” spray paint in hopes that it would mimic a natural material (inconsistent texture and color) and work to cover up any last marks or inconsistencies I didn’t manage to work out in the sanding process.
Once paint was finished, it was off to assembly in order to add the driver, legs, front wood ring, and cabling. The legs are constructed of simple 1/4”-20 bolts with hand turned wood upper sections.
Here the threaded audio terminals can be seen on the rear of the speaker. The threaded terminals ensure a secure electrical connection much better than most other connector types, and should keep these speakers in working order for quite a while to come.
So far these speakers have performed remarkably well, providing a punchy but not blown-out bass and lovely detailed highs. I certainly see this project as a success and have actually been in the process of designing new speaker housings from scratch to accommodate two drivers per speaker.