Resources

Argentium Silver

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

Annealing

  • 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


Quenching

  • Argentium Silver retains its heat for longer than traditional silver
  • Always wait until the red glow has gone before quenching to avoid cracking
  • Quench in water


Pickling

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


Hardening

  • 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.


Joining

  • 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


Casting

  • 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


Polishing

  • 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


Degreasing

  • 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.


Surface Passivation

  • 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


Long Term Care

  • Do not use dips as these will remove the germanium oxide surface layer
  • A simple wipe with a soft cloth will remove finger marks or dust
  • An occasional wipe with a silver polishing cloth will help maintain its shine

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