White Gold - Silver Alloys

Alloy #860

Purpose

  • Mix Alloy #860 with fine gold to obtain 10K or 14K White Gold for sheet, plate, and wire fabrication.
  • Can also be used for investment casting if desired.

Melting

  • #860 Alloy and fine gold should be melted together in a clean crucible. Put the alloy in the bottom of the crucible and the fine gold on top.
  • Initial melting temperature should be 1070° C / 1958° F.  Drop the temperature somewhat before pouring as listed below.
  • Boric acid flux should be used to keep the metal clean during the melting process. The molten metal should be mixed well with a stirring rod before pouring to assure a good mix.
  • A neutral or reducing cover gas is very helpful in melting white gold alloys.

Pouring Temperature 
for Ingots

  • 1OK   1040°C / 1904°F.
  • 14K   1010°C / 1850°F.

Pouring

  • Metal should be poured into a preheated, vertical graphite, or lightly lubricated iron mold.
  • A steady even pouring motion should be used, slowing down at the end of the pour to prevent shrinkage in the top of the ingot.
  • Use a round rod mold for wire, and a 2 piece L shaped mold for plate and sheet.

Quenching

  • Remove the ingot from the mold and allow to air cool - don't quench. Nickel white gold rolling alloys will be much softer if allowed to air cool after pouring and after annealing.
  • Soak ingot in a hot pickle solution to remove surface oxides.

Fabrication

  • The metal ingot should be cleaned of all adhering oxide or fluxes before rolling.
  • The ingot should be rolled or drawn to a 50% reduction in size before annealing.
  • Too small of a reduction can cause ingot to crack during anneal.
  • After annealing continue the reduction at 50% before annealing again. Clean the ingot after each anneal in hot pickle solution.
  • Keep the rolls, dies, and metal clean to prevent defects in the finished stock.

Annealing

  • Annealing temperature 732° C/1350° F for 20 minutes.
  • DO NOT QUENCH INGOT, allow ingot to air cool. 
  • A boric acid fire coat should be applied before annealing in an open atmosphere oven to protect the metal from heavy oxidation.
  • Clean the ingot in hot pickle solution to remove surface oxidation after annealing.
  • Avoid over-annealing wire, plate or sheet stock as this can cause excessive grain growth creating orange peel surface or poor strength in finished goods.

Re-Melting

  • Use a 30% scrap to 70% fresh mix on nickel white gold alloys.
  • White gold alloys have about 1/3 the re-usability of yellow gold alloys.

Investment Casting

  • Pre-alloy #860 and Fine Gold and pour into water to make shot.
  • White gold alloys have about 1/3 the re-usability of yellow gold alloys.

Pre-Alloying Temperature

  • 1060° C, 1940° F.

Casting Temperature

  • 10K     1040°C, 1904° F.
  • 14K     1000°C, 1832° F.

· Flask Temperature

  • Use somewhat hotter flask temperature.

Quench Time

  • 8 to 12 Minutes for invested flasks.

 

Alloy #940

Purpose

  • Mix Alloy #940 with fine gold to obtain 10K or 14K White Gold for casting.
  • #940 contains a silicon deoxidizer.

Melting

  • For 10K Alloyed Grain:  1030°-1040°C, 1886°-1904°F.
  • For 14K Alloyed Grain:  1000°-1010°C, 1832°-1850°F.
  • Melt Temperature for Alloying: 1050°-1060°C, 1922°-1940°F.
  • Pre-graining is recommended for all alloy and fine gold before casting to assure a uniform mixture.

Flask Temperature

  •  A slightly higher flask temperature is recommended for white gold.

Fluxing

  • Fluxing white gold is extremely important to pick-up oxides.
  • Boric Acid is the recommended flux. Do not use carbon fluxes or any fluxes designed for refining; i.e. soda ash, saltpeter, etc.
  • Avoid flux in bottom pour automatic casting units.

Quench Time

  • 10 - 12 minutes

Investment Removal 

  • Most standard investment removers will successfully remove the investment powder. Fluoric-based investment removers are the best for removing the silicon oxide invisible coating.

Re-Melting

  • 70% fresh - 30% scrap mix is recommended.
  • White gold alloy has about 1/3 the reusability of yellow gold alloys.

Notes

  • Melt temperature may vary with type of unit.
  • This alloy is designed for casting only.

 

Alloy #915

Purpose

  • Mix Alloy #915 with fine gold to obtain 10K-18K White Gold for casting.
  • #915 contains a silicon deoxidizer, and high nickel content.

Melting

  • For 10K Alloyed Grain:  1050°-1060°C, 1922°-1940°F.
  • For 14K/18K Alloyed Grain:  1030°-1040°C, 1886°-1904°F.
  • Melt Temperature for Alloying: 1060°-1070°C, 1940°-1958°F.
  • Pre-graining is recommended for all alloy and fine gold before casting to assure a uniform mixture.

Flask Temperature

  •  A slightly higher flask temperature is recommended for white gold.

Fluxing

  • Fluxing white gold is extremely important to pick-up oxides.
  • Boric Acid is the recommended flux. Do not use carbon fluxes or any fluxes designed for refining; i.e. soda ash, saltpeter, etc.
  • Avoid flux in bottom pour automatic casting units.

Quench Time

  • 8 - 12 minutes

Investment Removal 

  • Most standard investment removers will successfully remove the investment powder. Fluoric-based investment removers are the best for removing the silicon oxide invisible coating.

Re-Melting

  • 70% fresh - 30% scrap mix is recommended.
  • White gold alloy has about 1/3 the reusability of yellow gold alloys.

Notes

  • Melt temperature may vary with type of unit.
  • This alloy is designed for casting only.

 

Italian White Alloy 10-18K White All Purpose

Mix the Italian White alloy with fine gold to obtain 10-18K white gold for sheet, plate, and wire fabrication. 
This alloy is also intended for investment casting.

This is the premium white all-purpose alloy used in Italy that Lacy West imports for clients. Manufacturer's instructions are not available. Experienced goldsmiths do what they do best and obtain superior results with this alloy. All of our clients who have tried this alloy have continued to use it for 10-18K white gold.

 

S-88 Master Alloy

Purpose

  • S-88 is a master alloy for adding to fine silver to make Sterling Silver.
  • This alloy was developed for those who wish to alloy their own sterling.
  • S-88 will cast without fire scale.
  • The advantages over standard sterling are: reduced gas porosity (S-88 contains deoxidizers which resist oxygen absorption), reduced shrinkage porosity (better solidification characteristics reduce shrinkage), S-88 alloy may be reused indefinitely with a 50% fresh mix, and less finishing rejects from fire scale and porosity.

Melting

  • Traditional methods of melting regular sterling silver (i.e. as cool as possible) will cause a variety of problems. 
  • Most failures S-88 alloy are caused by too low of a melt temperature. 
  • Metal smiths familiar with silicon deoxidized gold casting alloys should have less trouble adjusting to the appearance of the silver.

Mixing

  • Use 92.5% fine silver & 7.5% S-88.
  • 92.7% fine silver & 7.3% S-88 is recommended. Example: 500 dwt, add 462.5 dwt of fine silver & 37.5 dwt S-88.

Melting and Casting 
Temperatures

  • Melting temperature for mixing sterling: 1040° C, 1904° F.
  • Temperature range for casting sterling: 990° - 1020°C, 1814° - 1868° F.

Fluxing

  • Boric Acid is the recommended flux. 
  • Do not use Carbon Containing Fluxes or Charcoal
  • Skim any surface oxides off the surface before stirring.

Quench Time

  • 15 - 20 minutes.

Hardness and  
Heat Treatment

  • This silver as cast will have a hardness similar to traditional sterling silver. It can be hardened further by heat treatment at 300° C / 575° F for one hour.

Investment Removal 

  • Most standard investment removers will successfully remove the investment powder. The best solutions are the sulfuric and hydrofluoric based products.

Re-Melting

  • 50% fresh mix is recommended.

Flask Temperature

  • Use your regular flask temperatures.

Notes

  • Fire scale is completely eliminated.
  • CYANIDE TREATMENT is Not recommended.

 

Alloy # 99 10-18K Yellow & White Gold Replenisher 

Purpose

  • #99 Alloy Replenisher is designed to de-oxidize used gold for casting.
  • Can be used for yellow and white gold.

Mixing

  • 10K scrap - Add 5 dwt #99, and 3.57 dwt of fine gold for each 100 dwt of 10K scrap being melted.
  • 14K scrap - Add 4 dwt #99, and 5.60 dwt of fine gold for each 100 dwt of 14K scrap being melted.
  • 18K scrap - Add 2 dwt #99, and 6.00 dwt of fine gold for each 100 dwt of 18K scrap being melted.
  • For white gold, the above ratios can be used, but use will be limited to 1 or 2 times due to the yellowing of the white color.
  • If #99 is to be used with scrap and fresh mixes in continuous reuse, use ½ of the amounts listed above. This will prevent excessive buildup of deoxidizers in the metal.

Melting

  • Place #99 in bottom of crucible when melting, with scrap on top.
  • When the mixture becomes fluid, stir with a carbon or quartz rod to clean surface of any oxides produced.
  • Fluxing may be necessary, depending on condition of old gold. Boric Acid is the recommended flux.
  • #99 will work best when old metal is clean from heavy surface oxides and investment powder.
  • If metal is contaminated with cuprous oxide (the red copper oxide), only limited positive results can be expected.

Notes

  • Use carbon rods only with gas fired furnace or torch melt.
  • Quartz rods should be used for all electric induction melting.