PB Cohen Creations

I have a love/hate relationship with patinas. I like the dimension created when you use them, but I would prefer more control over the process. This will never happen — it's the nature of the chemical reactions involved. So I try to resign myself to the occasionally unexpected results, and do it over (and occasionally over) when I'm not satisfied.

The chemical I use the most is liver of sulfur, and until recently I've only used the lumps or rocks that you dissolve in water as needed. But the supply at the Art Center recently lost its vim and verve, and — oddly enough, in terms of timing — so did mine. I'm not sure what the shelf life of this stuff is, but it isn't forever. Since I needed to finish a piece for the photo shoot, I ended up getting a quart of the ready-made liquid solution, since that's all I could get in town that day. Theoretically, since it's already mixed, I'll be able to get a similar look for all my pieces in the future, instead of getting slightly random strengths inherent in using the lumps. I'm not sure what the shelf life of the liquid is, so I may just try using it more often.

Charles Lewton-Brain wrote a nice tutorial on using liver of sulfur on the Ganoksin web site. The best advice I can give you is to experiment, and not to expect things to work perfectly on the first try ever.

The Art Center recently got some Silver Black, so I'll give a few additional tips on using both of these patinas on silver.

Silver Black turns the silver black almost immediately, which can be very satisfying. Liver of sulfur, on the other hand, requires keeping either your solution or the piece warm, and dipping repeatedly. It's a slow process. You can also paint the Silver Black onto your piece with a paintbrush, which gives you some very nice control over exactly where the "black" goes. Not so with the liver of sulfur.

A black Sharpie magic marker works as a resist for both chemicals. However, the heat required for the liver of sulfur can render the Sharpie marker a little less resistant. Rubbing alcohol will remove the marker, but remember to rub with paper towel or a cotton swab or something — simple soaking won't take it off. Once the patina is on, any sort of buffing or light sanding or application of steel wool or whatever your tool of choice is works equally well on patinas from both chemicals to polish high points of the metal, leaving lower areas dark.

If the patina turns out completely wrong, you can gently heat a piece treated with liver of sulfur with your torch and the patina will disappear. Not so with the patina from Silver Black — if a torch works at all (and I'm not convinced it does) you have to heat the piece so much that you'll risk losing your solder joins.

Silver Black turns silver black — or at least mostly black. The patina isn't always even, and it's more a dark grey than black. Some people don't think it's as rich a grey/black as you can get with liver of sulfur, but I haven't compared results enough to have an opinion; as far as I can tell they produce similar results if you're going for black. When used carefully and slowly, liver of sulfur will turn silver a range of colors, including browns, blues and greens. None of these colors are as durable as grey/black, though, so you'll have to fuss quite a bit with lacquer or a similar sealant, and even that might not work over the long run.

Both chemicals are toxic and should be used with care, ventilation and probably gloves.

Does anyone else have opinions or tips?

I hired a guy the other day to take some good photos of some of my pieces to submit to galleries and art fairs. This is a remarkably bad photograph of the event (I didn't want to disturb him at work), but it shows that this professional photographer is doing a few things that all the articles on the internets about how to take photos of jewelry tell you not to do! Like using the flash on the camera (well, this is a strobe). Or lighting only from one side (can you see that?). Or — and this picture doesn't show it — not using a tripod.

Seriously, by the end of the session this guy was holding the camera in his hands! He explained there's a "zen" involved in photography: you hold still, you take a deep breath, you let it out and hold it, and in that moment you can press the button without the force of your heartbeat shaking the camera while you're taking the picture.

Yeah. Snipers do the same thing.

It was fascinating watching him work. I'm always simply trying to get a decent photo of small, shiny things — you know, something that depicts the piece clearly. He was obviously trying to take a pretty picture. Occasionally, this drove me crazy. But for the most part it was fun to see someone so engaged.

I've learned that arranging jewelry for photographs is very different from arranging jewelry for display. I've learned that I need to spend more time cleaning/polishing before a photo shoot. A lot more time. I've learned that there are f-stops above 8 ("above?") (and that a quick look at my camera suggests it isn't capable of those — bummer).

It'll be a little while before the photos are ready. Can't wait to see them.

Like anyone who performs repetitive tasks regularly, jewelers have to be mindful of ergonomics. This is particularly true for people who hammer things regularly, like blacksmiths or traditional silversmiths. There was a day when I was working on my Bell Project that I did some damage to my left thumb, because I was holding the metal incorrectly, and taking too much of the force of the hammer on my hand. I quickly readjusted my methods, and luckily didn't do any permanent damage. My friend Stacy, who uses a hammer quite a bit, recently had surgery on one of her thumbs because of a stress-related injury. You can never be too careful about safety.

Hammering isn't the only potentially dangerous activity that jewelers participate in — any repetitive activity can cause problems if you do it for extended periods of time, if you perform it incorrectly (or without being mindful of your body), or if you don't take enough breaks. A good rule is, "If it hurts, find a way to do it so it won't hurt."

Jean left a comment on my post about sawblades, pointing out Brian Meek's "Frankensaw." He takes commercial, oven-bake clay, wraps it around the handle of his saw, grips it to mold the clay to the shape of his hand, and bakes it. You can click on this photo for a larger version, but be sure to go to Brian's site for more pictures and a how-to. As Brian says, the handle creates a "saw that you don't have to clutch to use," which would greatly reduce hand fatigue. He also describes the process in the article "Custom Saw Grip" from the August 2008 issue of Jewelry Artist.

I keep meaning to try this, but never remember to pick up clay when I'm out. Partly, I think, because it usually isn't my sawing hand that feels tired after a long session at the bench, it's my other hand — the one I use to hold the metal flat against the bench pin. So now I'm contemplating getting a different kind of bench pin. Contenti has two kinds of bench pins that include devices that will hold the metal for you: the Smartvise and the Clamping Bench Pin.

(Note that other jewelry supply companies have these, or similar products. I link to Contenti because it's easy to link to their photos.)

Too bad neither of these styles would help keep me from dropping 1/4" diameter circles on the floor.

While I make a lot of rings, I must admit that I have a hard time making a ring that is a specific size. In my defense, let me point out that there are only 2 1/2 millimeters' difference between, for example, size 6 (51.5 mm) and size 7 (54.0 mm). Rio Grande (jewelry supplier extraordinaire) provides a brief list of whole ring sizes (US and Canadian scale) and the corresponding length you need to cut the ring blank, near the bottom of this page.

[NOTE: It looks like Rio Grande has changed their web site, and I can't find that information anymore. However, Contenti has a nice PDF file here, and it looks like they've done all that math for you! Thanks, Contenti!]

When measuring the blank (that is, the strip of material that wraps around the finger), you also have to compensate for the thickness of the material. As Rio Grande's tip sheet says, "forcing the outside ends of the blank together for soldering will compress the inside circumference and make the ring" smaller. The company suggests adding 3.14 times the thickness of the blank to the length of the ring blank to compensate for this. In my defense, let me point out that, for example, 20 gauge metal is 0.812 millimeters thick, so if you're making a ring out of 20 gauge flat stock then you should add 2.54968 millimeters to the length of your blank. Right.

And it gets more complicated. A wider band fits differently on your finger than a thin band. Rio suggests you "add an additional 0.5 mm if the ring band is wider than 4mm" to compensate for this. Um, 0.5 mm? Really? I defy anyone to accurately add half a millimeter — by hand — to ANYTHING.

Add to that the facts that fingers change size in cold or hot weather (we're pretty sure that's how Julia lost the first ring), and I went and created a wrap-around design that made my life even harder, and you've got a recipe for disaster. And that's what happened. Here's the first step, a 3/8 inch strip of sterling silver:

It's a bad photo to begin with, and I got tired of fussing with Photoshop, so bear with me. Click on the photo to make it big enough to see — and upon closer viewing of the next photos, it looks like this picture is of what turned out to be the underside of the flat strip.

This strip is far too long for the ring: there are two faint marks on the right side, one of which (the angle) I've almost managed to enhance with a very thin black line. This became the pointy end of the finished blank, which overlaps the rest of the blank. The faint vertical line (not enhanced) designates the actual intended length of the blank. I soldered this pierced strip of silver on top of another plain strip of silver, formed the new strip into something resembling a circle, and soldered it together. After whacking it to get it round, and doing a bit of preliminary finishing, it looks like this:

I like it so far, but unfortunately, it's about two sizes smaller than I'd planned.

While I would never claim I can accurately add half a millimeter to the length of a ring blank, two sizes means I missed closer to 5 millimeters — and that I should be able to handle reasonably well.

So I'm trying it again, a little thinner than the 3/8" of the first. I haven't yet decided if I'll try the overlap again, but if I do I probably won't overlap a pierced triangle. In any case, I'm going to be a lot more careful about the math!

I don't know the history behind jewelry saw blade size "names." In the US at least, the available sizes, from smallest to largest, are: 8/0, 7/0, 6/0, 5/0, 4/0, 3/0, 2/0, 1/0, 1, 2, 3, 4, 5, 6, 7, 8. How did anyone come up with that? I don't see anything significant about "1" or "1/0" in any of the standard measurements — blade thickness or depth, teeth per inch, etc. Maybe it makes more sense in metric measurements? A quick search on Google didn't come up with anything. I might have to break out the books....

Jeweler's saw blades come in 16 different sizes, with different sizes recommended for different thicknesses of metal. Thinner blades are for cutting thinner metal, and thicker blades are for thicker metal. Supply kits at the Art Center, where I've taken several classes over the years, come with size 2/0 blades, which corresponds to the thickness of the metal supplied to the students: 20 gauge on the B&S scale (Brown & Sharpe). 20 gauge metal is 0.032 inches, or 0.812 millimeters thick. This is a reasonable gauge of sheet metal to give students: a little thick for earrings, a little thin for bracelets, but usable for just about anything.

The 2/0 size blade, which is 0.0100 inches thick, is designed to cut 20 or 22 gauge metal, and this is important for beginning students. 0.0100 inches is only about a quarter of a millimeter thick, it's very easy to break these things. At the Art Center, beginning students are given at least 24 blades; some students break many more than that during a semester. So anything to make sawing easier (like supplying blades that are designed to cut the supplied metal) is a good thing.

Some students hate to saw — in fact, some practiced metalsmiths I know hate to saw. But I was always good at it. Take a look at one of the first pieces I ever finished:

This is made out of brass (which is harder to saw than copper or silver), and is about 3 1/2 inches by 2 1/4 inches. Try to ignore the overall "design" of it! But take a look at those details (click on the photos to pop up a bigger version) — this is one of the first dozen or so cuts I ever made:

And this is the next one:

I don't mean to brag about my sawing abilities. I use a file to refine most of my cuts just like anybody — but I rarely break a blade, and I'm less annoyed by sawing than many people seem to be (maybe those are related). But my skill, such as it is, explains why I have so many 2/0 saw blades hanging around, and how I know you can use this size blade to cut just about any gauge of sheet metal — not easily, maybe, but it's possible. It might also explain why it's only been recently that I've bothered to try out different sizes of blades.

Click on this photo for a bigger version. From the left are saw blades 8/0 (the smallest available at 0.0063 inches thick), 2/0, and 5 (0.0160 inches thick). The scrap of silver is 20 gauge, with cuts made from the same blades, in the same order. The ruler at the top of the image shows 1/16 inch increments.

You can see that — if you're able to make saw blades your friends — you can use these different cuts, or kerfs, as design elements. More on that later.

NOTES: B&S gauge is equivalent to AWG or American Wire Gauge, but not the same as SWG, or (British) Standard Wire Gauge. Reade Advanced Materials (looks like a chemical supplier) has a Wire Gauge Conversion Chart.

The Contenti company (a jewelry supplier) has a Saw Blade & Drill Sizes guide available in PDF. The biggest jewelry saw blade available is an 8, which is 0.0197 inches thick.