The Skinny on Wire Gauges

The sizing of wire gauges is anti-intuitive - much like the sizes of beads. A bigger number means a smaller, thinner wire.

Wire is made by starting with a fairly fat rod of metal, and drawing it through a hole that is just slightly smaller than the rod itself. The end is tapered to get it into the hole, and then the wire is "drawn" or pulled through the hole, which stretches the wire out and makes it thinner, and longer. Each time the wire is "drawn" - a smaller hole is used, and the wire gets progressively thinner and longer with each pass. This is how a short fat rod of metal can be transformed into a long skinny piece of wire. The process may be complicated by the metal becoming brittle as it is manipulated and stretched, so that it needs to be softened by heating and cooling (annealed) during the process. And so, the number of times a wire was "drawn" - processed - related to the number that indicated it's size. Hence, a wire that had been drawn many times had a higher number, and a smaller size.

Ok - now that you have your head around that little factoid, many manufacturers of wire are switching to listing their wire in millimeters. When it comes to measuring wire of an unknown diameter, I have to admit that slapping a digital caliper on the wire to get the diameter is way easier than a traditional wire gauge. (I bought my digital calipers from Lee Valley Tools - a site I highly recommend if you are interested in tools, gardening, woodworking, and not-actually-getting-any-work-done. They have great catalogues too!)

Here is a conversion chart for relating wire gauge numbers to millimetres (mm). Remember, sometimes there isn't a perfect match.

Gauge	Millimeters	Inches Decimal
30	0.255	0.0100
28	0.321	0.0126
26	0.405	0.0159
24	0.511	0.0201
22	0.642	0.0253
20	0.812	0.0320
18	1.024	0.0403

Hauser & Miller have an excellent chart for converting precious metal wire weights to lengths, which can be useful - if you have directions for a project that say "take 1 ounce of sterling 18 gauge wire . . . " and all you know is how long your wire is.

But - what does it all mean? What gauge, or size, do you use and when?

Here are some rules of thumb. Remember that Fine Silver Wire and the Artistic (brand) Wire (which has a copper core) are softer (easier to bend) than Sterling Silver Wire.

14 gauge wire is a honking thick piece of wire. It can be excellent for making custom head pins for large lampwork focal beads. It is hard to bend - you will need good tools, and easy to mark while bending. The longer the piece is, the easier you will find it is to bend, so if you can slide your bead onto a long piece to do, say, a wrapped loop, and then cut it, it will be much easier.

18 gauge wire is quite strong, but still bendable. It requires tools for precision bends. You could use it as a base for a bangle bracelet.

20 and 22 gauge are nice, useful, middle of the road sizes. You can wire up beads, it is strong enough to hold it's shape, good useful size to have on hand at all times.

24 and 26 are more like the supporting players - great for wiring if you don't need a lot of strength and don't want a lot of weight. Good for earrings.

28 and 30 are very fine - use these for intricate projects that don't need a lot of strength - wiring beads onto a screen finding, for instance.

Think of wire like getting your kids to help with a move. The lower numbers are strong, but harder to get them to work. In their twenties, you start to see how they can be useful. Once they hit 30 - they are too refined to do much heavy lifting. ;-)

(Thanks to Wikipedia for the image of the standard wire gauge.)