Tuesday, November 11, 2008

Flexwire

string theory, part 4



Silk thread and wire links, the rosary-stringing methods of choice for most of history, are no longer the only choices. Within the last decade or two, there's been a revolution in the bead-stringing world. Various forms of plastic-coated wire are now the "string" of choice for many uses.

The first coated-wire product to hit the market (or at least the first one I became aware of) was "Tiger Tail," which is a miniature braided stainless-steel cable covered with nylon. Originally it came only in the natural silvery color of the wire, but you can now buy gold-colored versions too. In more recent years, Acculon and other companies have produced a number of variations, including different thicknesses and even more colors.

Unlike common crafting wire, which is generally made of soft copper or brass, these are mostly based on stainless steel wire, which is much stiffer and very springy. This is especially true of the early versions, which are braids of 3 or 7 strands of wire. More recently, manufacturers have produced 21- and 49-strand versions as well (three braids of 7 and 7 braids of 7, respectively). When more strands are used to produce the same size braid, the individual strands have to be thinner, and thinner strands of wire tend to be more flexible and less springy. This means that the 21- and 49-strand versions are considerably more flexible and "drapey" than the 3- and 7-strand types.

Flexwire (as I'll call this type of product in general) has some advantages over both wire-linked construction and fiber-based string, particularly if your main concern is sturdiness. Because the core of flexwire is metal, it can support very heavy beads, such as the denser types of stone beads. It's also very resistant to tensile stress -- it won't break easily when you tug on it, or if it catches on something. Tension breaks seem to be the main problem with most modern strings of beads, so this is a big advantage for makers of modern necklaces, bracelets and rosaries. The springiness of flexwire also means it's not very subject to breaking from metal fatigue, which occurs if a small area of wire is bent sharply back and forth several times and becomes brittle.

eclecticrosary
(This rather interesting modern rosary strung on flexwire is something I saw a couple of years ago on eBay. I have it labeled as "eclectic"!)

However, using flexwire also requires some differences in technique. Since it's hard to bend flexwire sharply, it's difficult to tie knots with it; the knots tend to resist tightening because of the wire's stiffness, and later to slip out because of the smooth nylon coating. This means that in order to secure the ends of the wire, instead of a knot you have to add a "crimp bead." These are small tubes of metal of just the right degree of hardness. The end of the wire is passed through the loop of a clasp, medal, or other ending and doubled back on itself. The crimp bead is slipped over both of the parallel wires and then squeezed with pliers to grip both wires tightly. This supplies the friction necessary to keep the wires from springing apart and the beads slipping off. (If a crimp bead is squeezed too firmly, it can cut through the nylon coating, weakening the wire.)

I'm much indebted here to Rosary Workshop and to the members of the Rosary_Makers mailing list, many of whom use flexwire to make modern rosaries. Several of them graciously answered my many questions about flexwire and any potential problems with it, and gave me permission to quote them.

Laura Eckert of Still Stone and Moss, for instance, did some testing of her own, and reports: "I held both ends of a piece with pliers and yanked as hard as I could. (I'm pretty strong.) After many mighty yanks, the wire finally broke -- right at the edge of the pliers. Could have been the sharp edge of the pliers that cut the wire. (For necklaces, I use a clasp that WILL break, so nobody gets strangled.)

"I tested crimp connections the same way. No crimps ever lost their grip. Even the crummiest crimps held -- this could be due to SoftFlex's nylon coating. Crimps closed with gentle pressure held as well as crimps closed with a death-grip. (I use crimping pliers -- the kind that first dent & then wrap the crimp.)

"I bent a piece of SoftFlex firmly at a U-turn angle with pliers, and the wire did "remember" that bend. Under ordinary conditions, it doesn't kink. For two-plus years, I've kept a rosary strung on 49-strand SoftFlex jumbled in the bottom of my purse -- when I pull it out, it falls into position without any weird bends. Rosaries left draped over the top of a 1/4" board for several months developed a slight bend, but returned to normal when suspended for an hour or so.

"No problems with abrasion to report after 4-plus years of use with a variety of beads, including stone & metal. No signs of wear even at the crimp points on a bracelet worn daily for several years."


Posts in this series:


String or Nothing
The thread thread
String Theory
Threads of silk and gold
Wired
Flexwire
Of flexwire and time machines

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