Tuesday, October 26, 2010

How to etch with Ferric Chloride

I use brass plates that I've etched with my own art work to imprint my silver metal clay. Here's a very quick tutorial on how I do it.

Create your art work

All my art work is done in either Adobe Photoshop or Illustrator (or both.) Above is the art for a custom piece that I did from the photograph on the left. It's been sized and is ready to print on to PNP blue transfer paper. The art work has to be black and white - no shades of gray.

Cut and prepare the brass sheet

Ferric chloride will etch brass and copper, I use brass because it's a bit cheaper. 20 gauge is plenty thick, and it's available at many hardware and hobby stores, and of course online. KC Engineering makes it in many sizes. After I cut it with my jeweler's saw, I clean it with Penny Brite copper cleaner and 220 grit sandpaper. Comet cleanser also works for this, just not quite as well. Clean metal is critical, water should sheet off the surface. If it beads up it's not clean enough yet. Dry the clean metal with a clean cloth or paper towel.

Print on to the transfer paper

I use press-n-peel blue transfer paper for my resist. It's available by the sheet at Whole Lotta Whimsy or by the package at Techniks. You have to use a toner based copier or laser printer to print your art, inkjet printers don't work. I have an inexpensive desktop laser printer that works great for this. I just make sure the toner cartridge is still printing very black. Since the paper is expensive, I just print what I need at the top of my document, that way I can trim the paper and keep running it through. You can also draw right on your brass to make the resist - I find oil based black markers hold up the best.

The tricky part

Now for the most troublesome part of the entire process, transferring the image from the pnp paper to the brass. This is done with an iron. Here in the US, all the irons have an auto shut off feature, unless you get an expensive "professional" model, which I finally did. The temperature of the iron is very important and you won't get a good transfer if it's too hot or not hot enough, and make sure the steam setting is off. I've found 275 farenheit works very well. I used to use a digital meat thermometer to monitor the temperature of my auto shut off iron. How long you need to apply heat varies on the size of the metal and the amount of large black areas in your art. This part will require some experimentation on your part to get good results, so stick with it even if it doesn't go well at first! The pnp instructions recommend 275 - 325 degrees, and 1.5 to 4 minutes. If the image doesn't transfer well, simply scrub it off with sandpaper and whatever cleaner you're using and try again.

You can carefully peel up a corner and check the transfer - if it's spotty give it some more time. Large areas of black can be difficult, but you can touch them up with an oil marker or a sharpie.

Success! All the black has transferred from the paper to my brass sheet. The black will resist the etchant, resulting in raised areas where ever the resist is. I've taped the back and sides, which will also resist the etchant.

The actual etching

I pour the Ferric Chloride about 3/4 to 1" deep in my glass dish. I run a long strip of tape over the back of the brass and suspend it in the liquid face down. You want it face down so the etched metal falls away. They don't have to be immersed, just fully in contact with the liquid. I use fresh solution every time and leave it in for 50 minutes to an hour. I do a lot of etching so I buy my Ferric Chloride by the gallon here, but you can get smaller bottles of it at Radio Shack - they call it PCB etchant. It's used for etching computer circuit boards, so if you're outside the US try looking for it at electronics supply stores.

You can check the progress, and yes, I should be wearing gloves. The longer you leave it in, the deeper the etch will be. I gently shake the dish to agitate the liquid every 10 minutes or so. This helps to get rid of air bubbles and makes for a smoother etch. You can try not agitating it to see the different results. After an hour the resist will start to break to down, especially fine lines, so I rarely leave it in longer than that. Once it's done I carefully remove the brass and rinse it, then I scrub the resist off with Penny Brite and my sandpaper.

The end result

Here's my newly etched sheet and the finished piece.

Thursday, October 7, 2010

What's old is new again

I've been trying to come up with a frog design for quite some time now, with no success. Then a few days ago I came across a necklace that I did waaaaaaay back in the early nineties that had a frog and a couple of snakes. I was working in wax and casting it myself back in those days. I liked the frog and one of the snakes so much that I decided to make them both. The larger piece on the left in both photos is the original casting. Silver cost around $3 an ounce then, it's currently $22 or so! The green dots are concrete.

Wednesday, October 6, 2010

New Tools!

Last year September was pretty slow for me, but not so this year! It was actually my best month so far this year, so I decided to get some tools that will help me during the holiday crunch. Above and below is my new magnetic tumbler. Even though I do a matte or brushed finish on all my work, I like to tumble it first and make it shiny, which leads to a nicer brushed finish (in my opinion anyway). I have a regular rotary tumbler with stainless steel shot, but it takes at least2 hours and is pretty noisy. This little beauty uses magnets to move stainless steel pins around the barrel. It takes about half an hour or so, and I should be able to do 20-30 pieces at a time. It was pretty expensive but I think it will be well worth it.

While I was shopping for the tumbler, I noticed flex shafts on sale and since this one has a quick release instead of a regular chuck I decided to get it too. I've been using a dremel, but with a foot petal this is so much nicer! I got both of these at Otto Frei, which is located in Oakland California. Their selection is on par with Rio Grande, and both these things were on sale so the prices were better too.