Problems with Wire Weight

4 05 2013

Again and again I run into the same problem: I can’t get the right weight of wire from supply stores. Silver and gold-filled wire are fairly expensive, so I try to buy just the amount I’ll need, plus a little more for scraps and damaged rings. At the supply store, I order what I will need, and I almost never get what I ask for.

The three jewelry supply stores where I get my wire are Santa Fe Jewelry Supply, Thunderbird Jewelry Supply, and Rio Grande Jewelry Supply–all reputable stores with good products and good service, and I shop at them regularly. But none of them get it right.

Here’s an example. I was going to make a gold-filled box chain bracelet, and I ordered 1.5 ounces of 20 gauge 14/20 gold-filled wire. The person who cut the wire gave me 1.4 ounces instead of the 1.5 ounces I wanted. That might not seem like a major difference, but 1.4 ounces is more than 2 feet shorter than 1.5 ounces! I was worried that I wouldn’t have enough wire to finish the bracelet. I modified the bracelet slightly and made it work, with maybe 5 rings to spare.

Why is it so hard to cut the right length to produce the right weight? It’s a simple math problem. The jewelry store people know (or should know) exactly how many feet are in an ounce of wire. For example…

  • 20 gauge, half-hard 14/20 gold fill: 21.68 feet per troy ounce
  • 18 gauge, half-hard  14/20 gold fill: 14 feet per troy ounce
  • 20 gauge, half-hard sterling silver: 19 feet per troy ounce
  • 18 gauge, half-hard sterling silver: 12 feet per troy ounce

When I ask for a certain weight, the person cutting the wire only needs to use this simple formula:

ounces x feet per ounce = the correct length to cut

Simple, right? When I asked for 1.5 ounces of the 20 gauge, half-hard 14/20 gold-filled wire, the person should have cut 32.5 feet of wire (1.5 ounces x 21.68 = 32.5 feet, or 32 feet, 6 inches). Instead, I got 1.4 ounces, which is 30.35 feet (or 30 feet, 4 inches).

I think the person cutting the wire is approximating the math in his head and simply guessing at the length to cut. This may be a little faster than punching numbers into a calculator, but it is not acceptable. I’m ordering by weight and paying by weight, so I want the weight I request. As in the example above, getting the wrong weight can be a problem. I’ll either get less than I need or more than I want to buy.

My Solution

My solution is simple. Because the wire cutter person is measuring out a length of wire, I’ll order by length. I’ll do the math for them. Instead of asking, for example, for 1.5 ounces, I’ll ask for 32.5 feet.

In fact, since my smart phone has a calculator, I can do it in the store. Most likely, though, I’ll do it at home. Before going to the jewelry supply store, I already know how much wire I want to purchase.

Now, my digital scale doesn’t measure troy ounces, which is how silver, gold-fill, and gold are sold. It can, however, measure standard ounces. But, even then, I can do the math.

1 ounce = 0.91 troy ounces

For example, if a bracelet weights 1.2 standard ounces, I need 1.1 troy ounces (1.2 ounces x 0.91 = 1.1 troy ounces).

Here’s the process I’ll need to use to get what I want when ordering wire, with an example.

  1. Determine what wire type and gauge to use (20 gauge sterling silver)
  2. Determine the bracelet weight in ounces (1.85 ounces)
  3. Determine the weight in troy ounces (1.85 ounces x 0.91 = 1.7 troy ounces)
  4. Determine the length of wire needed (1.7 troy ounces x 19 feet = 32.3 feet, or 32 feet, 4 inches)
  5. Add 5% for scrap and error (32.3 x 1.05 = 33.9 feet, or 34 feet)
  6. Order the amount that results (34 feet)

Now, let’s hope the wire cutting person is better with a yard stick than with mental math.

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One response

2 06 2016
theo

I suggest you make your own wire from scrap materials that you refine, melt, forge, roll, and draw yourself instead of buying pre-made wire. then you can technically call your items handmade instead of what they are: hand-assembled from 100% machine made parts. then you might understand some of the problems with “math” and how it doesn’t work in a three-dimensional model for rolling straight wire into complex shapes like jump tings. of course, you could be like 99.9999% of maillers who exclusively make world-class junk and lie about their quality; it seems you might be a step above these charlatan posers.

i agree that these three big companies are not all that great when it comes to competency, customer service, or math. still, FFS, an ounce is an ounce and there is no debating that unless you are TLR who illegally use regular ounces when selling their precious metals. you’ll never get what you ordered there, lol, but the arrogance and ignorance of the owner is something to treasure!

given the lack of competency of most maillers, their endless excuses for making junk products, and a vacancy of common sense among the industry, i would think that companies with similar philosophies are a natural fit.

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