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Friday, December 19, 2008

The Physics of Quilting

I used to be a math whiz in school. Not top of the class, just second. Ninety-eights, regularly. Used to yak with the teacher after class, discussing the 3-D images of these tangents and sin waves, etc. Used to have a blast with math. Used to love twisting all those strangely-shaped objects with even stranger names around in my head. If it could be calculated, I could do it, and have a ball at the same time.

Boy, has that ship sailed...

I love quilting. Both my hand and machine stitching are getting real good, something I'm quite proud of. But no matter how a project begins or progresses, there is an end.

The binding.

When I used to do flat, straight-on bindings with lapped corners, it wasn't a problem. But everybody knows you're not a REAL quilter till you do mitered corners on bias binding.

So, a few quilts ago, I cheerfully washed my binding fabric, dried and ironed it, looked at the instructions on my "Fons 'n Porter's Binding Basics" card, and cut my square of fabric. Then I cut it along the bias, flipped one piece a quarter-turn and over and sewed the seam that makes the two triangles hang like those little flags they string along car lots. I speedily drew my very straight lines along the long edge of the parallelogram that forms after you open up the shape. Then I read what you do to match these lines into a tube...

And came "bump" up against my new deficiencies in geometry and physics.

Which sides do I sew together?

I read and re-read the instructions. I tried several combinations of edges, each one more unlikely than the next. I sewed two of the edges together, looked at it. It didn't look anything like the picture. I ripped out the seam, ironed again, re-positioned and sewed, found that I had sewed the same two sides as last time...

In desperation I went to Hubby. Mr. Math. Mr. Computer. Mr Know-It-All. Mr. How Things Work.

Swallowing my pride, I asked him to read the instructions, look at the fabric, and see if it made any sense to him.

It made perfect sense to him. He was a bit uppity about his superior intellect in this matter, but he did get the thing sewn into a tube for me, and the lines were going round that tube in a lovely, even spiral. We cut something like 500 inches out of what looked to me like a fat quarter... I guess the square we started with was a little bigger than that, but the sheer length of the bias strip was daunting.

I suspected at the time that cutting a continuous bias strip in this manner actually CREATES matter. That you end up with more fabric than you started with. It feels like witchcraft. Magic. (And black magic, at that.)

Tonight I tried again, for a new project. Ironed, trimmed very carefully. Measured and measured. This time, though, Hubby was present in the room with me from the beginning. I wasn't taking any chances that boggarts or fairies were going to bugger me up this time! Oh no, with Mr. How Things Work in the room with me, I was sure no magical forces could come anywhere near me. It would be straight geometry, pardon the pun. It would be grindingly logical.

With only five or six arguments over how to cut off the selvages, how to get the fabric straight, how to mark straight lines, etc., we proceeded to the step where you have to offset the drawn lines by one, get the lines to line up with each other, and sew two edges together. Half way through pinning, we were deeply embroiled in another argument ("This looks NOTHING like the picture!", and "You must have drawn the lines along the wrong axis", followed by "You were HERE, in the room with me when I drew the lines! YOU must have put the wrong sides together!") etc. It appeared, after all, that the fairies had crept in unnoticed.

So I removed the pins, opened it out, and we compared what I'd done with the drawing and yes, I had drawn the lines along the correct axis. I watched as Hubby carefully pointed at the edges which needed to be put together. The same ones I'd been doing all along.

I pin-matched the lines one-quarter of an inch away from the edges of the fabric and proceeded to complete this part of the process. "And you're SURE," I demanded of him, "that I'm to sew THIS seam?"

Absolutely. I did it, carefully, with the quarter-inch foot on, just to make sure I didn't waver.

It did indeed form a tube, with lines spiraling from bottom to top, or top to bottom, depending on what you viewed as the starting point. And I carefully began to trim along these lines. Hubby stayed till I crossed the all-important seam, breathed a "Whew!" as it became apparent the process was working, that I was indeed cutting a spiral along a tube and we had in fact sewn the correct edges together. Hubby left, satisfied. But not before I noticed he'd been holding his breath along with me...

I continued to cut, and cut, and cut... I've got a couple of miles of bias strip now, whereas I started out with only a 42-inch square of fabric, and am once again convinced that magic has happened and fabric has been created out of thin air.

I, who used to float mental images of tetrahedrons in my mind for fun and entertainment, I cannot "see" how this works. I've been party to it several times, and it floors me every time. If Hubby had not been in the room with me, I would not have succeeded. I'd have ended up cutting straight strips along the length of the fabric and putting on a straight binding edge that overlapped at the corners.

I am mystified by this "tube". I cannot wrap my mind or my imagination around this system of getting an endless strip of fabric out of a square. I tell you this - it was an engineer who figured out how to do this. He, or She, might not hold the TITLE of engineer at any prestigious firm or university, but it is nevertheless a feat of engineering as surely as any bridge or tower.

Either that, or incredibly good magic.

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