Teaching by Demonstration, Using Epoxy to Hold it Together!

Two of my students decided early this past year that they wanted to create a 3D printed guitar.  It ended up turning out to be pretty cool!  Here is a picture of the guitar so far:

All of the pieces of the bass of the guitar were 3D printed using our PolyPrinter 229. We used 1.75mm ABS filament for our plastic. The bass section of the guitar turned out to be fairly weighty when all was said and done.  You may be asking yourself, how did he get those pieces to adhere to each other?  

First, the students created pieces of the bass of the guitar similar to that of puzzle pieces, they each had a unique shape and size and fit to a corresponding piece or pieces accordingly.  To get the plastic to stay in that configuration, I had the students use Oatey PVC primer and cement. We got the combination primer and cement from Lowe's.  It was this product specifically, Oatey PVC cement and primer combo pack. 

I was initially skeptical that the PVC cement and primer would work on ABS plastic, so I tried it out on some spare 3D printed pieces that we had lying around and by golly, it held them together mighty fine!  I was also concerned about any heat that the reaction between the primer and cement would give off, such that it might melt the ABS plastic since it is different from PVC; however, this is a non-issue, no heat problems to speak of. 

Now, the PVC primer is purple. Anything it touches becomes purple, forever. So, I told my students, that when handling the primer, they needed to be very cautious, they also wore smocks to prevent small splashing from getting on their clothing. I demonstrated how to apply the primer, thin coat, you don't need a ton, and then immediately apply the cement and hold the pieces together. We applied the cement more generously than the primer, but again, not a terribly thick coat, just enough to ooze out of the sides, to which can be sanded or cut off.  This turned out to work great! Each day we added another piece until the bass of the guitar was as you see in the above picture. It is still holding strong months later!  

I found another use for PVC primer and cement aside from using it to fix the PVC piping on a broken sprinkler system (yes, I had some experience of my own fixing some sprinkler related PVC pipe issues at my house).  I let my students know that this is a great skill to have in their repertoire, knowledge of using primers and cement to hold things together.  You never know when you may have to fix your own sprinkler pipe system!