Argentium Silver

The following contains guidance on best practises when working with Argentium Silver.

Argentium Silver displays a paler colour glow than traditional silver at red hot temperatures
It does not develop firestain
It will crack if moved or quench too quickly
It is advisable to anneal or solder in a shaded area to prevent overheating
Make sure it is adequately supported during annealing
Wait until the red glow had gone before quenching or it will crack
For furnace annealing: 600 – 650 Celsius for 25 to 40 minutes depending on thickness.
Do not heat it in a furnace using inert gasses that damage the tarnish resistant protective germanium oxide surface layer

Do not use hydrofluoric acid with Argentium Silver
Recommended pickling solutions are sodium bisulphate, weak Sparex, phosphoric acid or sulphuric acid

Argentium Silver can be worked when soft and then hardened using a simple heat treatment
To heat treat, make sure the piece is annealed and cooled to room temperature, then heat for 120 minutes at 300 Celsius in a furnace or oven.

Argentium can be soldered, fused and welded
There is a range of Argentium Solders available
Do not use Easy flo flux or Handy flux as these can stain the surface of Argentium Silver
For soldering, it is only necessary to flux the join, and not the entire piece
When fusing it is recommended to apply a diluted flux to the join

Argentium 935 and 960 Pro have been developed specifically for casting
Flask Temperature – 650 – 675 Celsius
Melting Temperature – 990 – 1010 Celsius
Melt under inert gas (Nitrogen or Argon)
Use separate crucibles to avoid contamination
Do not use silicon carbide crucibles. Clay graphite or pure graphite are recommended
Casting into a cold flask can cause cracking
The casted flask should be kept under inert gas for 1 minute before removing, alternatively, a flux can be added (boric acid)
The casted flask should be left in the casting machine for 3 minutes before moving
After removing the flask, let it stand for 20 minutes before quenching it, or it will cause cracking.
For stone in place casting, increase the stand time to 90 minutes, and remove investment manually

For tumbling use plastic or ceramic media
Argentium Silver is suitable for sanding with traditional abrasives such as sandpaper and abrasive wheels
For high sheen use walnut shells in a tumbler or polishing mops with traditional polishing compounds
For best results use separate polishing mops and media as this prevents cross contamination of other metals to the surface of Argentium which can affect the tarnish resistance

Argentium should be cleaned in an ultrasonic bath with pH 7 – 9 at 50 Celsius for 2 minutes and rinsed with water
Do not use deionised water as this can damage the protective germanium oxide layer
Make sure there is no oily layer on the surface of the ultrasonic solution as this can coat the surface of the piece on removal. If this occurs, it will discolour in air and give a false impression of a tarnish reaction.

A protective layer of germanium oxide will naturally form on the surface of Argentium Silver
It is possible to speed up this process with a simple heat treatment
Heat treat in an oven in air atmosphere at 100 Celsius for 3 hours. Ensure that pieces are thoroughly clean before heat treating

CPM Literature: