Sunday, June 16, 2013

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.

Sunday, June 2, 2013

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.