Silver Clays

PMC 3

PMC (Precious Metal Clay) and Art Clay Silver (ACS) are new materials on the art/craft scene. PMC and Art Clay Silver come in pure silver and 24K gold. NEW! PMC Pro, which has been released,  was announced at the 2010 PMC Conference.  PMC Pro is 90% Silver and 10% unknown (my guess is copper) – this makes the silver content less than sterling silver which is .925 silver.  To correctly mark jewelry made with PMC Pro you will have to use a .900 mark.  The Pro’s (hah) of PMC Pro is its strength.  The chart below shows a comparison of all the PMC clays, including Pro and sterling silver.  One note on this new clay – IT IS EXPENSIVE! About $113.00 (retail) for 50 grams (approx. 1 3/4 of an ounce) and a lot of that weight is moisture and binder – not silver.  As of 12/10, PMC+  is about $78.00 US for 45 grams ( about 1 3/5 of an ounce).  Less silver, more money?  Probably passing off the R&D costs to us consumers.  Thanks.  I’ll use sterling sheet instead – I can still get that for under $40.00 an ounce. As of 3/13/11 silver (in sheet and wire form) now runs me about 43.00 an ounce.  Wish the market would stop going up – pretty soon I’ll be working with gravel!

Each type of PMC has special properties, as summarized here.

Comparison of Precious Metal Clays
OriginalPMC® PMC+™ PMC3™ PMC Sterling™
PMC PRO™
Sterling
– cast –
Metal Fine silver Fine silver Fine silver 92.5% silver alloy 90% silver alloy- 92.5% silver alloy
Metal
Content
77% clay weight 90% clay weight 90% clay weight 90% clay weight 90% clay weight
Shrinkage (size) 25–30% 10–15% 10–15% 15–20% 15–20%
Suggested
Firing
1650ºF
120 min.
1650ºF
10 min. +
1650ºF
120 min.
1000ºF in air/30 min.
1500º F in carbon/30 min.
1400ºF in carbon/
60 min.
Elongation 15% 30% 35% 28% 30% 35%
Tensile Strength 60
N/mm2
 130
N/mm2
140
N/mm2
190
N/mm2
210
N/mm2
310
N/mm2
Bending Strength 30
N/mm2
 50
N/mm2
30
N/mm2
160
N/mm2
150
N/mm2
 240
N/mm2
Surface Hardness
( Vickers)
 n/a  30 HV 30 HV 50 HV 60 HV 60 HV
Density 7.9 g/cm3 9.5 g/cm3 9.9 g/cm3 9.3 g/cm3 9.7 g/cm3 10.4 g/cm3

 

Art Clay Slow DryThe differences between these brands of clay is subjective as well as chemical.  See Tim McCreight’s and Darnel Burks comparative testing of PMC 3 and Artclay 650 (notice the picture on the bottom left of the hand, carving a piece – that’s my hand and my piece!).

For more information on Art Clay see: Art Clay World.

Metal clays are mixtures of very small metal particles with an organic binder and water.  The clays are elastic and are similar in texture to modeling clay.  They can be molded, coiled, stamped and – in an air dry state – can be drilled, carved and engraved.  There are few limits on the uses of these clays.

Briefly, creating with metal clay is as follows:  the object is formed using the moist clay,  all the moisture is then removed by using either an electric heat source or allowed to air dry. Next, the object is fired in a kiln or exposed to another source of high heat, like a torch, at a range of temperatures  generally between 1200 degrees F to 1650 F. These temperatures vary depending on the type of clay being used. Bronze, copper and steel clays have different firing requirements.  See my page on Bronze and Copper Clays.

Firing causes the piece to shrink and the resulting shrinkage needs to be accounted for in the design.  Shrinkage rates vary from 8% to 30% depending on the type of clay.  Firing sinters*  the metal, burns away the binder and leaves behind  pure metal.

To learn more about PMC please visit the  PMC Guild .  For Art Clay Silver see their site here: Art Clay World USA .

Shopping for Clay

You can find PMC, Art Clay Silver at:  Cool Tools, Metal Clay Supply and Rio Grande, to name a few of my favorites.

Videos

PMC Videos/Art Clay Silver Videos: Discover Art Clay Silver! The Metal Clay Academy has many videos relating to metal clay.  Art Jewelry Magazine has many videos too!

Magazines and Publications

The PMC Guild publishes Fusion, which comes out quarterly (I believe) along with a copy of the PMC Annual which is published, hmm…Annually!  My work is in issues #1, #2, #3 and #4.  Yippee!

There’s a new kid in town (as of 2010): Metal Clay Artist Magazine.  This is a beautiful magazine full of great new ideas and images.

Art Jewelry Magazine regularly features articles on Metal Clay.  We love Art Jewelry!

* Sintering:  a material is heated below its melting point until the particles adhere to one another.