Platinum & Palladium
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Palladium RU
Alloy Composition 95% PD (RU/AG ALLOY) Colour White Melting Range 1450 – 1500°C Solders PD E,H, 1020, 18HW Specific Gravity 11.7 Annealing Colour Cherry Red
Best used for
• Bench Work
• Casting
• RollingHints, Tips & Uses
• White malleable light-weight metal that is easy to polish
• This metal will not cause skin irritation
• Do not rhodium plate this metal
• If casting metal do not hammer
• Casting temperature: 1600°C
• Flask temperature: 700-800°C
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Platinum CU
Alloy Composition 95% PT (CU) Colour White Melting Range 1740 – 1755°C Solders 1020, 1200 & 1400 Specific Gravity 20 Annealing Colour Cherry Red
Best used for
• Bench Work
• Casting
• RollingHints, Tips & Uses
• General all purpose alloy
• Medium to soft alloy
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Platinum RU
Alloy Composition 95% PT (RU) Colour White Melting Range 1780 – 1800°C Solders 1020, 1200, 1400 & 1600 Specific Gravity 20.7 Annealing Colour Cherry Red
Best used for
• Bench Work
• Casting
• RollingHints, Tips & Uses
• General all purpose alloy
• Universal alloy which can be cast, machined and used for bench
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Platinum COBALT
Alloy Composition 95% PT (CO) Colour White Melting Range 1740 – 1755°C Solders 1400 & 1600 Specific Gravity 20.8 Annealing Colour Cherry Red
Best used for
• CastingHints, Tips & Uses
• High hardness and fine grain
• This alloy is magnetic and very hard
• Preferred for casting
• Used for fine wire & chain making
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Platinum AU
Alloy Composition 95% PT (AU) Colour White Melting Range 1740-1755°C Solders 1020 & 1200 Specific Gravity 21.3 Annealing Colour Cherry Red
Best used for
• Bench Work
• Casting
• RollingHints, Tips & Uses
• General all purpose alloy
• Medium to soft alloy
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Polishing Platinum
• When polishing platinum, it is important to remove all scratches before the polishing process
• When filing, file gently with a diagonal movement. Then repeat with a diagonal movement perpendicular to the first one.
• Remove file marks with abrasive paper such as 400, 600 and finer paper
• Be sure to use the files and abrasive paper on platinum to avoid contamination
• Reduce the surface to at least a 600 grid finish on the bench
• Burnish the ring with a polished Tungsten burnisher
• Use platinum polishing compound only for luster
• Use 2000, 4000 and 8000 grid polishing compounds
• When polishing platinum that is joined to gold, be sure the platinum is polished completely before polishing the gold
• Check with tool suppliers for brand recommendations
Things to consider• File gently with a diagonal movement. Then repeat with a diagonal movement perpendicular to the first one, creating a criss-cross pattern
• Because gold polishes faster than platinum, it is easy to over-polish the gold portion by trying to polish the platinum and thus ruin the piece.
• Hard felt whells and stitched buffs work well on platinum
• Burnishing is essential
• The polishing process will highlight, rather than remove scratches. They must be removed at the bench
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Burnishing Platinum
Why Burnish?
Burnishing will work-harden the surface, compress it, close small cavities and make polishing easier. When done properly it reduces rejects from the final polish and saves time. Benefits of burnishing Platinum:
Burnishing adds extra hardness to the casting, preventing a score of problems such as bending, taking on the shape of the finger, and scratching more easilyReference guide to burnishing:
All platinum casting should be burnishedHow to burnish:
Using a highly polished tungsten burnisher, rub across the surface of the piece of jewelery. Note, burnishing can also be accomplished using a motor toolTips for better burnishing:
• Use a small amount of oil to lubricate the burnisher. This prevents scratching and makes a smoother surface possible
• Any scratch on the burnisher will be transferred to the piece. The more polished the burnisher, the better the surface of the piece will be burnished
• Use considerable pressure and force. This action will move the surface, compress it and close small porosity holes. The rubbing action hardens the surface, making the final polish much easier.
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Contamination
When contaminated platinum is being stressed through rolling, drawing or hammering, it will crack and become unusable
Possible causes of contamination during soldering or welding:
• Using carbon soldering surface (charcoal)
• Abrasive rolled into the Pt surface during fabrication
• Filings from other precious or non-precious metals.
• Using flux or Fire coat on Pt during high temperature operation
• Using steel tweezers near the soldering flame
• Oil, grease or soap used during drawing, rolling or general workingTips to avoid contamination:
• Use only oxidizing flames, avoid redusing flames during soldering or welding
• Avoid trapping contaminants in the Pt during cold working
• Dedicate files, sanding sticks and bench pins to platinum
• Do not weld or solder with acetylene / oxygen flames
• Use only Natural gas / Oxygen, Propane / Oxygen of Hydrogen / Oxygen
• When using a water torch, disable the flux featureTips on what not to do:
• Don’t use Acetylene Gas. Only Natural Gas, Hydrogen or Propane will work with Platinum
• Don’t weld without eye protection. UV radiation WILL damage your eyes
• Don’t weld when stones are nearby. The welding process will damage most stones
• Don’t use your soldering pick or steel tweezers near the flame, as they may contaminate the platinum
• Don’t weld on a charcoal block. Platinum and Carbon do not get along.
- Working with Palladium
- A guide to Platinum Alloys