Etching Metal Part 1: The Resist

This three part post on etching is in conjunction with my upcoming demo for the Metal Clay Artisan Guild in Connecticut.

I have been working in metal for almost two decades and it all began with etching.  During a printmaking class in high school I learned to etch zinc plates with Nitric Acid for intaglio printing and fell more in love with the surface qualities I could create in the metal than the final prints.  I have used these basic techniques for years in my own work and in my classroom.  From printmaking, to sculpture to jewelry, the technique is relatively the same, it just varies in size- also, today I have found safer materials to work with than nitric acid and asphaltum.  The information in these next two posts is what I use to successfully etch copper, nickel and brass metals.

1.  Prep Your Designs & Your Metal

Start by figuring out what you will eventually use the piece for.  Will it be the actual piece of jewelry? Maybe it will be a stamp for polymer work? Maybe it will be a plate for embossing paper?  Or maybe it could even be a texture plate for metal clay?  In any case, you want to determine your size and draw or print the original artwork or copyright-free image you are using the exact size and shape you will eventually etch.  The cleaner and sharper your image is, the better it will work in the end.

Prep your metal by first cutting it to a size slightly larger than the design you want to etch, it also must be flat.  Next, clean it with a super fine steel wool pad to remove any oils that might disrupt the resist or the etch.  After this point, be careful not to touch it with your fingers, only hold it by the edge.  Immediately before you apply any of the below resists, wipe the piece down with rubbing alcohol.

2.  Create Your Resist

You will need to create a "resist" on the surface of the metal to protect the part of your design you would like to keep raised.  The etching process removes the metal that is left exposed.  You can etch sharp clean lines or large backgrounds can be removed.  This needs to be decided during your design.   There are many ways to create a resist on the metal, here are three simple and safe materials to use as resists.

PnP Resist (Press-n-Peel blue acetate film)

If you have a very precise image or are trying to transfer a photograph, one of the best ways to get your image on the copper is using PnP paper.  You can photocopy your image to the matte side of the PnP paper using a copy machine with a carbon based toner.  In my experience, printer ink does not generally create a successful resist.  You will then iron it on to the metal with the matte side facing down to create a resist, as you iron and the image becomes more and more visible through the acetate, the resist is transferring.  When the metal has cooled, pull up a corner of the PnP to check your design, if you need to you can lay it back down and keep ironing.  If there are small areas that need to be touched up, you can fill them in with black permanent marker or nail polish.  You will need to protect the back of your design with contact paper or electrical tape and then seal the edges with nail polish to prevent them from being etched.

There is a great article on PnP you can find on the Ganoskin Project site that you can follow a link to here.

Tips for PnP Resist:

-Run the copy machine until you can get the darkest (and cleanest) copy possible on white paper before copying on the matte side of the acetate.

-Be prepared to test your iron on scrap metal.  Since every iron is different, you will need to have some extra PnP and scrap metal to do test strips.  My iron at home requires the highest setting for almost 10 mins to get the small size transfers in this post, the iron in my classroom requires a lower setting and less time.  Begin on your highest setting and move the iron in circles until the image becomes clearly visible or the acetate buckles.  If it buckles, turn the iron down.  Hold the acetate with tweezers down in one corner and peel up with another pair of tweezers from another corner to check transfer.  Continue ironing as needed.  I generally time my test strips in 3 minute increments.

Tape Resist 

Using either masking tape or clear plastic packing tape, make a "tape sandwich" with your metal in the middle.  Make sure to seal all the way around the edge, this will stay in place during the etch to protect the back and sides.  Rub the tape down to remove any air bubbles. Then either draw or tape your design on top of the tape, leaving a border of tape to protect the edge.  You will then use an exacto knife to cut out your design.  In this case, I am cutting the design and removing it in order to etch the lines of the designs.  The tape will be left on the background area to protect it.

Permanent Marker Resist 

Choose a high quality permanent marker and draw your design directly on the clean metal.  Make sure it is a rich, solid black with no transparent areas.  Make sure there is a border to protect your edge and seal your back with either electrical tape or nail polish.

Aquatint Texture Resist

The same technique used to etch printmaking intaglio plates to create a stippling effect is great to create a texture background to hold a patina.  You can either use it to create a simple texture piece or in the background of any of the above resist methods.  Simply spray a mist of spray paint LIGHTLY across the back of the piece of metal in a quick sweeping motion.  This should leave "dots" randomly across the surface.  Experiment with the density of the spray and the effect you get from the etching, this is another time you will need to do test strips to get your desired effect.  Here, I drew an image with permanent marker and "swept" it with spray paint to create the dots in the background which will be our texture later on.  You can see how light it is, the darker it gets, the more you are blocking out the etch.  Don't forget to protect your edges and your back.

If you want to learn more about etching methods in printmaking, check out the great site artist Julie Niskanen has on intaglio process by clicking here.

3.  Etching the Metal

Once you have prepped and applied your resist to the metal, visit my next blog post (here) to learn how to complete the etching process.

Same Technique, Different Sizes...

All of these pieces were done using the etched copper method in this blog post.  These were all specifically done using a masking tape resist, as described above.  From the 6' long hanging sculpture (right) to the 14" x 18" framed etching (left) to the chunky cuff bracelet (above), the same method has endless possibilities.

  

Repoussé Effects in Metal Clay

Repoussé is a traditional metalworking technique where a raised or relief surface is created on the front of the metal by hammering a design from the back of the metal.  It is a french term whose origins mean to push from behind.  It is often used along with another traditional technique called "chasing" where the design is then sharpened or refined from the front by sinking in the metal on that side.  The effect of repoussé and chasing creates what is often referred to as embossing.  You are dealing with the elastic qualities of a malleable metal, so there is no actual loss of metal. 

This is a relatively simple technique to replicate in metal clay while the material is in its clay state.  It is a great way to incorporate original designs and textures, even for the beginner artist.  You will need something to create your impression with, the pieces in this post were done using scratch foam, so that is the process I will focus on here.   Scratch foam is a popular and economic material used in basic printmaking.  If you think it is an elementary school material, check out the sophisticated prints by artist Annette Mitchell who is able to get woodcut-like imagery from recycled meat trays.  If you can not find it at a local craft store, you can always use cleaned foam trays from the supermarket.  Just cut yourself a square to work with.

Begin by working out a simple design.  I did a series of pieces based on swirling cloud patterns, they all began with the same frame, but I played with the interior a little differently on each piece.  I like working out designs like this on tracing paper so that I can quickly replicate elements I am happy with.  I then tape the tracing paper to a piece of scratch foam and lightly go over it with a ball point pen, just enough to get a slight indent in the surface.  I then use an embossing tool to go over the lines, but maintain medium to light pressure.  Each time the lines will become more pronounced, but I don't end up ripping or wrinkling the foam.  As the lines get deeper, I change the gauge of the embossing tool if I want thicker lines.  The key is patience until you get a feel for the right pressure on the foam.  If you are looking simply to create texture sheets to emboss with, you can use anything you can dent the surface with from a comb to a meat tenderizer.  Keep in mind the scratch foam has a more "smooth" side and a more "rough" side, you will need to look closely at the foam to discern this, I recommend carving into the smooth side.  In any case, the surface of the clay will pick up the surface of the foam, which is more subtle on one side than the other.  

Once the design is carved in the foam, I lube the foam so the clay will eventually release.  I set my rolling slats (or cards) on top of the foam on either side of the design a little thicker than I want the piece to account for the raised areas.  If the piece of foam is too small to support the width of the slats, I lay additional slats (or cards) next to the foam to keep them even.  I then roll my clay into the design the same way I would roll it onto any other texture plate.  I then gently pull it off and trim the excess.  Once dry, they are fired and finished the same as any other piece.  The bonus of the scratch foam is that it is relatively inexpensive and fairly forgiving.

A few tips about scratch foam... 

If you chose the wrong side and this impacts your design (which you will be able to see as soon as you pull it off) simply smooth  your metal clay piece with a damp sponge - as long as you are light with your pressure it will clean up the surface without removing the embossing.   Also, remember this is a printmaking process - you are essentially creating a "stamp" that you are embossing your piece with so your design must be the REVERSE of what you plan.  In a symmetrical design this does not matter, but in the design of a piece like I did here it can make a difference.  I planned it backwards because I have done this enough times to think about it that way.  If you are not quite there yet, this is another good reason to workout designs on tracing paper, because you can then lay them on the foam on either side.  If you draw your design exactly the way you want it, you should then lay the tracing paper face down on the foam.  It will reverse the design on the foam and come out the way you intend in the clay.  Since it's tracing paper, you can see through it and can still easily trace it.

FastFire BRONZclay Success!

After feeling a bit "burned" by base metal clays a few months ago, I went ahead and tried a new brand on the recommendation of jewelry artist Evelyn Pelati.  I went with FastFire BRONZclay by Metal Adventure and was happy with the results for a variety of reasons.  Here are a few...

To begin with the obvious, it fires fast.  It takes an hour to ramp and an hour to fire.  It is a one phase fire, so set the kiln and forget it.  I was looking for a base metal clay to use with multiple classes, so I do not always have the luxury of being able to run a multi-phase firing during my teaching schedule.  This allows me to not have to return to run a firing on my own time. 

There is the other obvious of the price, with bronze clays being around 30 cents a gram and silver clays being more than $2 a gram, it is the most economical, especially for introducing it to a large class.

The firing directions are clear and easy, particularly if this is your first attempt at base metal clays.  The descriptions of what you will find out of the kiln and what that means for your firing temperatures are also clear.  I was able to figure out my firing schedule after just two test fires, though I have had to make adjustments based on running a whole class worth of pieces at a time.

I have also been able to successfully fire in a ceramic firing vessel.  Since I am flip-flopping between silver and bronze, depending on the class, I am running multiple firings a day.  When you fire in a steel pan there is a black flake sort of fire scale that needs to be vacuumed from the kiln after your firings.  With a ceramic vessel, there is no evidence of the base metal firing.

Last, the workability of the clay has been great.  It has a silky flexibility that makes it great for draping and forgiving for students just learning to work with it.  When it dries, it is easy to reconstitute and continue working.

These were a couple of quick test pieces where the clay was rolled into scratch foam designs and run through the firing.  The bronze has a warm gold hue and nice weight once fully sintered.  

Carving in Metal Clay

This week's challenge was to translate a carved design into the top of a ring.  I was inspired by this bright pink 8mm CZ and couldn't resist the temptation to nestle it safely into a lily pad.  The perfect pink floral accent to the top of this piece.  I balled up my clay and squished it into a flat pancake the same height as the CZ.  I poked a hole with a straw and sank the CZ in until the top of the clay surrounded it.  I then cut out my initial shape of the lily pad and let it dry.  Once bone dry, the clay is very easy to carve, especially at this thickness.  I find that small diamond files are the best carving tools in this dry material.  It has a similar feel to plaster carving.  I began with my general design and deeper lines and then carved the more detailed texture, each time lightly scratching or "drawing" in my design before begining to file.  The secret is no pressure.  The tools are sharp and just need to be trusted to do their job.  I added a coil to keep the eye moving around the piece and finished the ring with a liver of sulfur patina to bring out the richness of the texture.

  

On the Road...

Taking the studio on the road this week, I found myself surrounded by some great local artisans at Get Baked Bakery in Windsor Center.  It was a delicious celebration of Art and Spring!  Thanks to all the familiar faces who braved the beautiful weather to stop by and say hi :-)  Looking forward to showing with all these fine artists again!

Tool Tip: Stone Setting Trick

Setting tiny stones can be frustrating at times.  There are great shaped tweezers for picking up pearls or or other larger shaped pieces, but what about a small stone?  I recently saw that companies are now selling "Stone Pickers" to help with this, which is a great solution, but one you really can do for yourself without the extra charge.  Any pointed tool, from a pin tool to a dental tool, with a small ball of wax or even poster putty on the end creates the sticky finger you need to place the stone.  If you are having trouble with it rolling off the tip when you have it in place, a pin tool in the other hand can give it a gentle push into place.

Tool Tip: Taming the Tumbler Shot

Back in December, I posted about using a tumbler to polish up your finished pieces in an article titled:  Tumble & Shine (that post can be read here.)  As the pieces rotate in the tumbler they are surrounded by steel shot and cleaner, this means there is always the chance of that shot getting lodged in open areas, whether it is an enclosed bail or openings in a hollow form.  I'll admit that I'm the first to throw caution to the wind and opt for taking the risk of running an item through the tumbler to see what happens.  I have a series of hollow organic forms that have a lace-like outer-surfaces that always trap the shot.  In these cases I usually end up trying to pick it out with small tools or simply sitting at my bench and shaking and shaking (and sometimes cursing) and then shaking some more until I get them all out.  After seeing my pieces, another jewelry artist asked if I was tumbling them and suggested I try putting pipe cleaners through the openings to block the shot.  Above, you can see they look a little silly, but were well worth the suggestion.  They tumbled for about 3 hours and the pipe cleaners held up fine.  I was suspicious that the one on the right that was full of openings and now surrounded by pipe cleaners might not get much benefit from the tumbler, but I was wrong.  I did intentionally leave the pipe cleaners wide open to allow the shot in and it worked, tumbled up nice and bright.  In the piece on the left the pipe cleaner is run through the bail, twisted to stay in place and then the end was bent in to prevent it from scratching other pieces being tumbled.  In the piece on the right, the ends of the pipe cleaners are forced into the openings and bent into positions to hold themselves in place, I was expecting some to have fallen out by the end of the tumbling, but they were fine.  This was a great tip that should save me a lot of time in the future!