Showing posts with label trigonometry. Show all posts
Showing posts with label trigonometry. Show all posts

Friday, August 29, 2014

sterling silver tubes

 Buying and cutting those colored aluminum tubes that I've talked about in the last few posts has started me off on a tear.  I've thought for a while about using oxidized sterling silver instead of oxidized copper, but was put off by having to cut the tubes myself.  At the same time I knew that there were things I couldn't do with the copper tube lengths I had, that I could do if I could control the length myself.  So as soon as I had worked a bit with the aluminum tubes, I found myself buying silver tubes and cutting them up too.
  As a practical matter, the price difference between copper and silver isn't so very great because the necklaces don't actually have that much metal in them. They're light as a feather.  In fact, that may be a problem in some pieces down the road.  On many of my copper pieces I used some 18mm melon shaped beads, mostly to add a little weight to make the piece hang better.  But those same beads in silver are pretty pricey because they have a lot of silver in them.  For now, the time it takes to cut and, more importantly, de-burr the cut tubes adds more to the cost of the work than the difference in metal prices.  And I think silver has more customer appeal than copper.
   The piece on top, with the tetrahelixes, was my first one with oxidized sterling.  I find it doesn't oxidize as dark as the copper does, at least using liver of sulphur.  There may be other chemicals that make it darker if I decide I want that.  For now this is OK.  I felt I needed seed beads at the ends of the aluminum tubes, so I used them at the ends of the
silver tubes too.  On the second piece, below, I used them just on the aluminum, not on the silver.  As I was cutting the silver, I found I was seduced by how pretty the bright silver was, so for the second piece, I left it bright (also the dark blue and purple show up better against the bright silver).  However, as a practical matter, I don't want to spend a lot of time trying to clean silver, so I think I'll mostly darken it.  I've looked at a lot of Flora Book's work with silver tubes, and it's so beautiful it tempts me to do more with bright silver. I'll just have to see as I go along.
  On the bottom piece you can see the advantage of cutting my own tubes.  It's a simple chain of octahedrons.  But a chain of octahedrons would normally form a straight line.  In order to get the curve you need for a necklace I had to make the triangle on the outside edge longer than the triangle on the inside edge.
Here's where some trig would have come in handy in figuring out just how much longer, but I managed to figure it out with "lesser" math, and it came out right.

Saturday, July 5, 2014

tetrahelix

   I haven't posted in  while, but I've been playing with a spiraling structure of tetrahedrons that I mentioned a few months ago. In the interim, the beaded molecule folks talked about the same structure in their blog, so now I know it's called a tetrahelix, i.e. a helix made of tetrahedra.  I borrowed their idea of accenting the spiral-ness by using different color beads for the 3 outside edges of the helix. 
   I've been thinking for a while about using different tubes to contrast with the oxidized copper.  To do that I have to cut my own tube beads, but that opens up lots of possibilities too, because I can vary the length to alter the structures.  I suspect that soon I'm going to wish I knew some trigonometry.  My only memory of trig is looking up 4 digit decimal numbers in tables in the back of the math book.  This was, of course, in the bygone days before calculators.  But now I find myself wanting to know things like what angle I'm creating between 2 faces, or  2 beads, and I think that's the realm of trig.  One of the nice things about doing this stuff with beads is that if the angle is close to what you need, you can make it work.
   In this piece I didn't play with angles and lengths.  Learning to saw the tubing was a first step and that was enough for starters. I bought gold filled tubing and cut tubes the same length as the long copper ones I've been using.  I like the effect.  Another possibility is stainless steel tubes ( which are actually hypodermic syringe tubes), or anodized and colored aluminum.  The stainless would, of course, be much harder to cut, and I like the idea of colored aluminum, but the tubes I've found so far are much fatter than the copper ones, so I'm not sure they'll look right if used in the same piece.  So much to learn (and such fun doing it!).