Dan Gottesman graciously offered quite a few photos he took of our project. Here they are in chronological order.
We started out by carving a few slabs off of our block. We used a chainsaw with a 42 inch bar and a helper handle to follow lines scribed into the ice. At first we tried etching the lines with sharp things, but we eventually figured out the easiest way we had to mark the ice was with pencil. The pencil markings could be erased quickly with a chisel.
Breaks in the warming hut were essential as the temperature was rarely above -15°F. I heard that the average temperature during the competition was -23°F and that it was the first time in the history of the Single Block Classic that it never exceeded 0°F over the course of the three day event.
We used small, electric chainsaws to carve parts out of the slabs. Here is one of the saws next to one of Lars's homemade chisels.
We tried cutting slabs at night, but it turned out to be tricky. At temperatures below -20°F or so, the ice tended to crack. We never lost a whole slab, but some significant fractures appeared along the edge closest to the gas engine of the giant chainsaw.
Lars noticed that the exhaust port on the saw pointed directly at the ice where it had cracked, so we decided that slab cutting would be a daytime-only activity until a modification could be made back at the shop.
We were fortunate to have the aurora borealis overhead as we worked into the night. It is always a treat to see the lights in Fairbanks.
This display was fairly bright and active. There were two distinct bands of light that rippled quite a bit.
We were worried about how long an axle we would be able to turn on the lathe, but we ended up having no trouble producing axles of more than 50 inches.
Roughing out parts with chainsaws turned out to be the safest nighttime activity.
The drill press carriage assembly and custom 3.5" drill bit Lars made worked wonderfully.
Here you can see a hole ready to receive a lathe-turned axle.
We had some scary moments while assembling the chime frame that consisted of three horizontal shelves. The extreme temperatures made it difficult to waterglue ice. As soon as more than a few drops water or slush hit the ice, significant cracks appeared. Also, the frame pieces didn't fit together as well as we would have liked, mostly due to our slab cuts not being perfectly planar (though they were much better than last year's). The middle shelf broke apart into several large pieces while I was trying to level it for gluing. I was amazed that the lower shelf stayed intact when all the pieces landed on it. After that event, we came up with a bonding method that caused less cracking and also allowed for less precision: spreading a layer of dry snow between the parts, wiggling them into position, and then spraying the snow with a small quantity of liquid water.
Throughout the competition, we followed diagrams in a book I had printed using QCad. As the event wore on, we made more and more notes and modifications to the designs in the book.
Lars used a hot tube cutter ("the boiler") with a sheet steel template to carve the hammer.
The boiler worked well but very, very slowly. Unfortunately, it tended to create cracks in the ice, especially when used at night. We had the same problem with hot wire cutting, so we came to the conclusion that heat cutting is generally useless below about -20°F (maybe higher). If we decide to use heat cutting in the future, we will have to warm the ice up to a workable temperature before doing so.
As night fell on Thursday, we were working on the final assembly of our simplified music box. We had to pack a considerable amount of snow between the front frame pieces in order to get the axles aligned correctly. Ice was cracking like crazy when it came in contact with more than the tiniest amount of water, but I found that I could get the snow to stay in place with just a little moisture from my own breath.
I brushed snow off of the piece while Lars worked on the last few parts.
The cracking power cord on the die grinder held up just long enough for Lars to finish the bushings needed for the axle assemblies.
I kept scraping and brushing snow off the ice until the bushings were finished.
Just before the horn sounded, we put the axles in place with all of the parts attached. Unfortunately, it wasn't until the next day that we were able get the music box working.
No comments:
Post a Comment