Spongebob. The single greatest TV show of all time. And the best single greatest character of all time, Squidward.

Process 

We started by finding the STL design we wanted to make on thingiverse, squidward’s house from SpongeBob (Image 1). We began by sizing the file down 50%, and 3D printing it. We decided this was a good size for our final pieces, and imported the piece into Meshmixer. We split the piece into two pieces down the middle, and decided we’d CNC the back half and 3D print the front.

Image 1: STL File

We then worked in Solidworks, and attached our pieces to bases with holes/pegs in them, so we could attach them during the molding process. We also aligned our piece with the bottom of the base, so we would have a place to pour in the plastic. From here, we started with 3D printing one of the sides, which was a relatively easy process (Image 2). The milling side, however, was a different story. There was a lot of problems with the machines, one of the main ones being it would get half way through a cut and then shift to a couple millimeters to one side, effectively ruining the entire cut (Image 3). It was frustrating, and took more time than anything else in our project, but we learned a lot about the machine and it was satisfying to get a final cut (Image 4).

    

        Image 2: Final 3D Print                    Image 3: Failed Print                          Image 4: Final Mill Cut

After we had our two pieces created, we made the mold using cardboard. We made the watertight boxes, and poured the alginate in until it fully covered our pieces. We let it sit for a couple hours, and then used the finished pieces (Image 5) to cast the house out of plastic. We mixed the plastic and used a lot of rubber bands to hold the mold together while it dried (Image 6).

  

  Image 5: Alginate Molds                                                                         Image 6: Mold Drying

Our finished pieces are shown below! (Images 7-9)

  

Image 7-8: Final Pieces!

Image 9: All Finished Pieces!

Successes & Failures

Our pieces turned out pretty cool, and we learned a lot in the process. The only drawbacks were that in  our pieces, there were some deformations due to imperfections in the mold blocks and the way they connected (Image 10). Our milled piece also had a lot of lines on it, something we could have avoided if we used a 1/16 in. mill to do our finishing piece. However, this cut would have taken a couple hours, and we decided to just use the 1/8 for the final cut.

Image 10: Some Imperfections

Cost

• 3D Print Filament: 1/40 x $19.99 = $0.50 (Amazon)
• Wood: 1×12 in. piece = $15.85 (Amazon)
• Urethane A & B = 1/10 x $75.99 = $7.60  (Amazon)
• Silicone A & B = 1/10 x $36.97 = $3.70 (Amazon)
• 20 hours of labor x $10/hour x 2 people = $400
• Total = $427.65