This week in ENGI 210, we were tasked to CNC small pieces of wood with a design pulled from thenounproject.com. Having experience using the XCarve last semester and using the Carvery once for my midterm here in 210, I was excited to practice and expand upon my CNC skills. Since I 3D printed anatomical hearts for last week’s homework, I decided to stick to that theme and CNC images of anatomical hearts onto wood for this week’s homework. SVG files of anatomical hearts were plentiful on thenounproject.com, and I picked this one:
When looking through old versions of the assignment from last year, I discovered the tactic of staining wood then quickly wiping the stain off so that the inside of the wood would retain its color, to be shown through the CNCed image. Because I wanted to utilize this tactic, my first order of business was grabbing two rectangles of wood out from underneath the 210 table and staining them mahogany:
One thing I forgot to do before this was sand the frayed edges of this wood. After the wood stain was dry, I headed downstairs to take care of this, and wasn’t surprise that some of the stain ended up being removed. At first I figured it wouldn’t be a big deal to go back and add more stain to the spots where sanding removed the color, but then I decided that the lightened edges gave a sort of antique look to the pieces, which I was fond of and decided to keep:
The next step was to actually use the Carvey to mill the design into the wood. This was the result:
I was very happy with this! The only issue was that the heart was spaced closer to the top than the bottom of the wood, due to the position of the bottom clamping mechanism, which I didn’t want the bit to run into. I needed to slice a bit of the bottom of the rectangle off in order to make the spacing around the heart even and pretty. This was at a point where it was too late at night for lab techs to be around, so I tried my best with a combination of a handheld power saw and the belt sander downstairs. One of the two pieces ended up looking nice, but the other had super uneven margins (due to my habit of being over-zealous with the sander). See the unevenness here:
I decided to try again and see if I could get some more uniform looking pieces. Knowing that something could potentially go wrong, I stained three more pieces of wood to be safe, and planned on cutting two of them. I also decided to only stain the front and back faces of the wood and none of the edges, because I wanted to paint the edges later on. At first, I thought it would be convenient to just cut out the margins using the Carvey itself. After all, this type of cut on a small piece of wood is supposed to be its specialty, right? Unfortunately the piece of wood was so small that adding the rectangular piece was going to interfere with the clamps, as shown here:
I resigned myself to the idea that I’d have to somehow cut the margins by hand, and cut two more hearts on the new pieces I had stained the night before. (I decided to make two more instead of one more because I had already messed with the size of the heart file and knew I’d never know exactly what its size was to match my original iteration.)
At this point there were actually lab techs around, so one of them helped me use the band-saw in the machine shop to cut these pieces down to size.
Beautiful! All that was left was for me to sand down and spray paint the edges. The final result was this:
Cost Analysis:
Wood: I found a 2’x4′ piece of 3/4in plywood from Home Depot for $32.47, which would be more than enough to cover the different iterations I did.
Stain: I also found an 8oz can of mahogany wood stain from Home Depot for $4.48.
Rags for staining: Home Depot, 6 pack, $2.98
Spray paint: Home Depot, metallic silver spray paint, $6.97
Machines: free for use at the OEDK
Time: 7 hours at $10 an hour is $70
Total: $116.9, split between the two pieces is $58.45 each!
