Texas Coasters! | ENGI 210: Prototyping and Fabrication

Hi again! For our CNC project this week, I decided to make Texas coasters that I plan to give to my mom for Christmas (let’s hope she doesn’t see this).

I chose a file from the Noun Project and moved the star to be where Houston is using Adobe Illustrate. I also added a circle around the shape to be able to make it a circular coaster. I created my file in Carbide Create, following the instructions in the document. I set the star to be a pocket cut of depth 0.2″ and the area surrounding the Texas shape to be a pocket cut of 0.1″. I set the outer circle to be a contour cut to the depth of my wood.

At my tutorial with the TAs we had some difficulty. We couldn’t get the gcode from my Carbide Create file on the computer next to the Shapeoko Pro, so I had to recreate it in VCarve. Then, I was able to successfully cut my first piece. However, I didn’t plane the wood before, so there were some unwanted impurities and texture. I sanded on the belt sander, and got a visible improvement! I started my second piece by planing the wood. I made sure to vacuum and clean up the space afterwards.

I measured the depth and length of my second piece and adjusted those accordingly in VCarve. I couldn’t access the same file I had before, so I had to create the toolpaths again. I clamped the wood down. I used a 1/16″ bit for the star, so had to change the tool during the cut. I used a 1/8″ bit for the pocket cut around the Texas shape and to cut the coaster out. I made sure to put the bit back into the correct container afterwards and put it in the organizer where I got it from. My first attempt was unsuccessful and the pocket cut started to go off the side. I stopped the cut early because the contour cut would have gone off as well.

I got a new piece of wood and measured the width and depth again. I jogged and homed the device again. I ran the cut again and this time it was a success! I vacuumed the sawdust and cleaned up my workspace.

The piece didn’t cut perfectly centered, and as a result, cut off the side a little bit. The side of the coaster wasn’t perfectly round. I hand sanded this side to make it less visible and was pleased with the results. I don’t think someone would notice now without me pointing it out or intentionally studying it. The piece of wood I picked for the second coaster had some indentations on it. I used the belt sander and successfully removed most of them, and made the piece overall more smooth.

However, because I sanded the bottom of the second coaster significantly, the two coasters were different thicknesses. I used the belt sander to sand coaster 1 down more so they were roughly the same height. I also lightly sanded the top of both pieces again, and hand sanded the sides.

I then moved on the staining my coasters with Tung Oil. I wanted to leave the wood showing for the Texas symbol, so I thought tung oil would enhance the look nicely. I left my coasters to dry on the drying rack. When I came back the next day there was some spray paint on my front coaster. It seems like someone spray painted their piece on the drying rack and some accidentally got some on mine. Thankfully, the color didn’t contrast the wood too much and wasn’t too eye-catching.

Next, resin! First, I made red resin and filled the stars. I then made blue(ish) resin to surround the Texas symbol. Please observe the good safety measures I followed by wearing a glove (appropriate PPE) on one hand. I handled the bottles with the other hand to ensure they didn’t get sticky. I cleaned up my workspace and set the coasters on the table to dry.