Etching and Medallions

I’ve been playing around with etching for a while. Modern etching is accomplished in two parts: an etchant and a resist. The etchant is what eats away at the metal you’re etching, and the resist is the thing that keeps parts of your subject from being etched. This means you’re always etching negative space, and you have to remember this when you work up your designs.

I started off doing saltwater etching with an adhesive vinyl resist.  Saltwater etching is a good place to start, because it involves no toxic chemicals, and low-voltage electricity. I used my vinyl cutter to make stickers, stuck those on axe heads. Then I used a battery charger, wires with alligator clips, saltwater and cotton balls to etch the cut-out area of the vinyl sticker into the metal. This is super fast and super easy, but the results aren’t always great and you can’t to fine designs with a vinyl resist. Still, it was a lot of fun and a good starting place, and the results were good as long as I kept them simple.

But I wanted to start making SCAdian award medallions. A household full of new folks (which I founded, but am not an official part of) that I’m close to is starting to get awards – a couple of Golden Alces so far, with a Master Bowman or two on the horizon – and I thought it’d be nice to be able to give them cool award medallions. Master Artemius, a stained glass and jeweler Laurel from the Barony of Delftwood, was a great help in showing me the ropes of acid etching with a photo resist. Here’s how it works:
1. Make your design in black and white. Use Photoshop, GIMP, MS Paint, whatever your graphics program of choice is. Personally I’m familiar with Paint Shop Pro, so I use that. You want a high-resolution vector graphic; if the resolution is too low your design will be pixellated, and the pixellation absolutely WILL be visible in your etching – that’s how precise it is. Remember that the black parts of your design will NOT be etched – that’s the resist. Another helpful hint is to work in a place for a hole to hang it by. Sometimes I put these on the outside of the medallion, and sometimes on the inside – depends on the design.

2. Print your design, using a laser printer, onto glossy photo paper. I’m using this stuff: https://smile.amazon.com/gp/product/B00AN5WTTM Cut it out leaving as little excess around the edges as you can.

3. Cut your metal to size. I usually make 2″ medallions, and I buy my metals in 2″ strips from www.onlinemetals.com. Specifically, I have been buying Nickel Silver 770 H02 and  Brass 260 in 0.05″ (16 gauge) and 0.125″ thicknesses. The 0.125″ thick stuff makes delightfully heavy and substantial medallions, but it’s a pain and very time consuming to saw. The 16 gauge stuff is a lot lighter, but I can rough it out with my Beverly shear, which is a huge time saver, and it’s much faster to saw, too. The 16 gauge medallions are lovely too, just not… substantial-feeling. Master Artemius says it only takes him ten minutes to saw out a 0.125″ medallion, so I suspect I need more aggressive saw blades for my jeweler’s saw. Or more practice. Or both.

4. Using a regular household iron, high heat, no steam, heat up your metal for thirty seconds, then, as precisely as you can manage without burning yourself, place your face-down printed photo paper resist onto it. The glossy paper will almost immediately stick to the hot metal, so you really only get one try. You can put the resist paper onto cold metal, but you run the risk it’ll slide around – because the next thing you do is iron the paper onto the metal with substantial pressure for five to seven minutes. Move the iron around continually. If you keep grabbing the paper try using a piece of parchment paper between the iron and the paper. Use the tip of the iron to press down every area of your resist.

5. After five to seven minutes of ironing, WITHOUT burning yourself, move the metal to some water. It’ll cool fast, and once it does, use some pressure from your fingers to rub and peel the paper off the metal. It will leave behind all the toner, giving you a perfect resist:

If you have small imperfections in your design, you can touch them up carefully with a Sharpie or some nail polish. If it’s absolutely bollocksed up, you can quickly remove the photo resist with some acetone and try again. It comes right off with a toothbrush and nail polish remover.

Finally, you’ll want to cover the back of the amulet too, to retain the smooth factory finish there. I use adhesive vinyl for that, and Sharpie on the edges if they’re very close to the edges of my design. I think electrical tape will work if you don’t have vinyl around.

6. Once you have a good resist down, it’s time to etch! I use ferric chloride acid: https://smile.amazon.com/gp/product/B005T8Y20W  This stuff will etch any copper alloy and any steel. Put your blank into a plastic, glass, or ceramic bowl (flat bottoms are most efficient), using toothpicks to keep it off the bottom. Put it in face-down so that the particulate matter falls down and doesn’t impede the etching. Be careful not to have the toothpicks over your resist – the areas that the metal is touching the toothpicks also won’t etch, so don’t obscure your design.

Pour in enough ferric chloride to cover the medallion, and set a timer for two hours. Very simple, blocky designs can go a bit more, designs like the Alce above need to go a bit less, otherwise the acid starts to eat away at the really fine details from the sides. After about 30 minutes, wearing gloves, remove the piece your etching and give it a quick rinse in water, just to loosen the first bits of particulate matter, then put it right back.

After two hours, take it out, thoroughly rinse it in water, and responsibly dispose of your acid. Use a toothbrush and some acetone to scrub off the photo resist, and uncover the back and clean that too.

7. Saw your medallion out, drill your hanger hole(s), clean up the edges with a rotary tool or belt sander or files, and polish the edges and back. I do all my polishing on a pedestal-mounted buffer, but you could do it with polishing wheels and rouge on a Dremel or on a drill held in a vice, or even with sandpapers of increasing grits up to about 2000. A final wet sand with 2000 grit will give you a mirror shine – it just takes a lot longer than my buffer does.

8. Enamel it. I’m using Ice Resin: https://smile.amazon.com/gp/product/B00HQP2YK6  It’s not cheap, but it works great. I tint it with a drop or two of acrylic paint. Less is always more with the paint, don’t use too much. I use Vallejo hobby acrylics that come in dropper bottles. Mix the paint in with the resin thoroughly, then CAREFULLY apply it to the medallion. I use a sharpened toothpick to do this. It’s painstaking work, and takes a long time and a steady hand. If your colors are widely separated, you can do them all at once, but if they’re close together, I highly recommend you do one color a day until it’s done.

9. When your enamel is all dry, you’re done except for adding a jump ring and a cord or chain.

Here is a small gallery of some of the medallions I’ve done so far:

No documentation, as this is not a medieval method or craft that I am aware of.