## Saturday, December 10, 2016

### New scaffold with gold

I've just finished a scaffold piece with accent tubes of 14 kt gold.  Structurally it's similar to the one with blue and green accents below, with 2 exceptions.  Both are based on chains of tetrahedrons.  The sides are tetrahelices, but at the bottom I've massed larger groups of tetrahedrons.  They're based on the idea that 5 tets that share a single center edge, like a hub, will form a circle.  You can see such a group of 5 at the center bottom in each piece.  Trouble is it doesn't actually work.  For it to work exactly the angle between sides of a tet would have to be 72 degrees (I don't have a font that will write math symbols) so that 5 of them would add up to 360.  But it's actually around 70.5 degrees.  It would work if the hub tube were a little longer than the others.  But when you start extending
the structure as I've done at the bottom of the piece you can't do that because a tube that is a hub in one group is a spoke or rim in other groups.  So things don't quite work, and it gets worse the further you go. One of the reasons I've added small seed beads at the ends of each tube on the bottom piece is to add more "wiggle room".
But a while ago my favorite blog, (thebeadedmolecules.blogspot.com) showed a picture of the 8 possible convex deltahedrons ( ie convex shapes made exclusively from equilateral triangles) and one of them was essentially my 5 tet circle but without a hub tube at the center.  That got me thinking, and in the new piece I left out some of the hubs where I could.  Just leaving out 5 tubes made it fit together much better.
The other change I made was where the necklace curves around your neck at the back.  You can take a tetrahelix and go off in a new direction that's about a 30 or 40 degree change (I've never measured it).  I did 2 such jogs in the bottom piece to get to the clasp.  It's fine, but I wasn't entirely happy with the sharpish corners that stick out.  So in the new piece I made the tetrahelix curve by simply shortening the inside tubes, and it makes a smoother finish.
I'm really enjoying working with gold tubes.  I think the contrast with the dark silver accentuates the geometry nicely.  What I have to be careful about, though, is that the high cost of the gold tubing has a tendency to make me more conservative about what I make.Starting out, most of my gold pieces, like this one, are variations on designs that I already know I like.  But if it works, I'm sure I'll get braver.