Saturday, April 4, 2015

Asymmetrical silver tetrahedrons

Seems to me that I have a way of announcing in a blog post that I plan to do A and then immediately doing B.  Like I'll say I want to get away from symmetry and the next thing I know I've done 3 or 4 symmetrical pieces. Or vice versa. Just a few posts ago I said I wanted to make pieces using sort of stock lengths of tubing instead of cutting custom lengths for an individual piece, because if I get the geometry wrong, I'm left with odd length pieces that don't work and that could  produce a lot of waste. So what did I do next but make the most custom length piece I've made so far.  I'm sure there's a CAD-CAM program out there that could have figured out the proper lengths for me, but, of course, I don't have one.  For this one I drew the inside oval and the outside asymmetrical curve on graph paper, and then drew the triangles it would take to join them.  This gave me an approximation of the lengths I would need, but only that.  Beyond that it was pretty seat-of-the-pants. I've been mostly oxidizing my silver so I don't have to think about tarnish, but for this one I had no choice but to use bright silver, because I was cutting 2 or 3 lengths at a time, and there's no sensible way to oxidize the tubes that way. (If I were still working with copper, I could oxidize as I go, because copper doesn't need hot water to oxidize, but for silver you need very hot water, close to boiling.  I guess I could keep a liver of sulphur bath hot if I used a hot plate, but I just use a pot with a coil immersed in the water, so I can only heat plain water, and when it starts to cool I throw the bath out.) Also if I oxidized a tube and then had to shorten it a bit,I'd be left with 1 bright edge, and I'd have to oxidize it again.  Anyway, I like this one in bright silver anyway, so it worked out alright.  the longest tubes in it, by the way are 62 mm, or around 2.5" long.

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