Monday, March 16, 2015
Main Setbacks
My main setbacks were having to start over with different cans, and missing in-class work days. I should have been more efficient in getting new cans once I realized the Orangina cans weren't going to work. If I had gotten new ones faster I wouldn't have had to do as many makeup steps. For one work day I was sick, and for another I was on retreat, so I came in after school or during my resource about 4 times to work on my engine outside of class.
Crank Shaft, Push Rod, CD, Balloon
The three hardest parts about building the engine were attaching the PVC pipe to the side of the can, constructing the push rod attached to the balloon and bending the crankshaft. When I first applied the epoxy to the PVC and the can, the PVC was not straight so I had to quickly adjust and fix it; that was nerve wracking. The crank shaft was a HUGE challenge for me, my first attempt had to be abandoned completely and I went in after school to get some help building it. I had to redo my second wire about 3 time before I finally got the bends right and it fit with my cans. Gluing the CD to the crank shaft was relatively easy. The balloon push rod was also really hard. It was really hard to get it to go straight up and down, it kept pushing at an angle and twisting up my balloon. Again I had to come in after school and tinker with it for a long time before I finally got it straight. It was also hard to attached the rod to the crankshaft and not have it slip around. I also had additional problems with the balloon because it didn't have a complete seal. I ended up having to take the balloon off, with the push rod attached, and put it back on with a better seal. Miraculously, the balloon didn't rip (Mr. O'Keefe didn't have any extra balloons left either) and my engine ended up working that afternoon. Assembling the Cans
Assembling the cans was definitely a challenge. When I pressed the top can into the bottom one, it created a pretty big rip in the bottom can. The pictures show how I used epoxy to really carefully fill the rip and keep the seal between the top and bottom cans. I had to be SUPER careful, because if any of the epoxy leaked into the bottom can and got on the displacer, it would inhibit the displacer's movement and my engine wouldn't work. Thankfully after the epoxy had dried, my displacer still had a full range of movement and the rip was completely sealed. Piercing top can, music wire, displacer
When punching through the bottom of the can, most of the needles at my table weren't effective, they bent rather then piercing the can. The needle I brought was a lot thicker and was the only one successful in making the small hole. When threading the music wire through the displacer it was really hard to get it to go straight through. I almost ruined my displacer by putting the wire through too many times and making too large a hole in the foam. However, with the epoxy I was able to fix it by smearing a little epoxy over the hole. The epoxy had an unpleasant smell and was hard to work with. I had to be very deliberate about where I applied it and it was difficult to smear it with the popsicle stick, especially if there was dried epoxy on the stick. I eventually got the wire secured with the epoxy successfully. Sanding the PVC pipe
With my NEW cans, I used sand paper to make the edges of the PVC pipe fit snug against the side of the can. While I was sanding I realized that its hard to make both the top and bottom parts of the PVC opening fit against the can, to get the bottom part sanded down, you needed to press extra hard and give it extra attention. New Cans
I finally got new cans and started the entire process again. I drew the lines, and now that I had practiced, they were a lot straighter then the ones I drew on my initial cans (orangina). The 7up cans had thicker aluminum and therefore it was a lot easier to cut them without getting really jagged lines.
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