Platinum Guru

Welding Platinum

In a platinum application, welding is different from brazing because platinum is joined together by heating the metal until it is fused together.  Therefore, as a guideline, you should weld when sizing a ring.  However, it is not possible to torch-weld different Pt alloys together as they have different melting points.

 

  ~Jurgen

Eye Protection

Proper eye protection is important when melting platinum, since the ultraviolet light emitted by the glowing melt can damage your eyes.  Use only lenses that are approved by the federal Occupational Safety and Health Administration and comply with American National Safety Institute standards.  A #10 welding goggle is the absolute minimum protection for the caster, and we generally recommend a #11 or #12 lens to be safe.  Do not, under any circumstances, use regular sunglasses or other dark lenses!  Any jewelry tool supplier or welding supply house can provide you with the proper eye protection, as well as gloves and a leather apron-two other important safety items.

  ~Jurgen

Welding Platinum,Jewelers Tools,Platinum Jewelry

Platinum Torch Fuels

Selecting the proper fuel to work on platinum is of utmost importance.  Do not use acetylene, since it has a very high carbon content and expels carbon in the flame, the platinum will absorb the carbon, leading to contamination and brittle castings.

Although propane, or LPG, is also a carbon-based fuel, it does not have the high carbon content that acetylene does, and therefore can be used for platinum.  Be aware, though, that even when mixed with oxygen, propane does not burn as hot as hydrogen and thus requires more time to melt the platinum when casting.  This longer melting time can lead to porosity caused by gas absorption or debris - a direct result of keeping the metal in the melting crucible too long. 

The most efficient way to melt platinum is with hydrogen combined with oxygen.  This fuel is carbon-free, and the high heat created by a proper hydrogen/oxygen mix melts platinum in seconds.  But even with hydrogen, a proper flame is crucial: If it’s too big, the flame will heat the surrounding crucible, adding to the melt time-and creating the same problems as those with propane.  Use as much oxygen as necessary to make a relatively small but oxidizing flame.

  ~Jurgen

 

Jewelers Tools,Platinum Soldering,Casting Platinum

Platinum Welding Goggles

Through a Glass Darkly: Protecting Your Vision – Without Limits

When soldering and welding platinum you MUST have proper eye protection.  The melting temperature of platinum alloys can reach as high as 1,780 degrees C and only #5 safety goggles will do.  However, goggles can sometimes limit your vision, which in itself can be a hazard.  What is a good solution?  Attach a protective lens to your light fixture.  Now you can view the work being done behind the lens with full vision, and maximum safety.

  ~Jurgen

Jewelers Tools,Welding Platinum,Platinum Jewelry

Joining Platinum to Gold

If platinum is being joined to karat gold, it is important to finish the platinum segment completely prior to assembly.  Failure to do this will result in the over-polishing of the karat gold component.  Platinum will not oxidize during brazing / welding.  Therefore, the platinum finish will not be altered by the process.

  ~Jurgen

Soldering Platinum,Making Platinum Jewelry,Bench Jeweler

Soldering VS. Welding Platinum

Soldering is usually required when you are working on a multi-metal piece, such as an 18K and platinum combination.  The metal with the lowest melting point dictates the method used. When installing minor components to Platinum, such as findings, soldering is preferred.  Whenever you are sizing a ring and need to use solder, use a 1700 seamless solder to do the task.  Lower temperature solders tend to show a seam.

Sizing a platinum ring is normally done with the welding method, as long as there are no stones nearby and the ring is made of platinum.

The exception here is Pt/Co, as cobalt oxidizes.  To size a Pt/Co ring, the 1700 seamless solder is recommended.

  ~Jurgen

Platinum Jewelry,Soldering Platinum,Bench Jeweler

Soldering Gold and Platinum Together

When soldering gold and platinum together make certain to anneal both parts thoroughly before soldering.  These metals expand at different rates when heated.  If not thoroughly annealed stress tears may develop as the metal cools.  In addition, allow the metal to cool slowly after soldering.  Do Not quench the hot metals, rapid cooling increases the stress in the metals.

~ Brad

Platinum Jewelry,Fabrication,Casting

Soldering Platinum to Gold

When soldering platinum to gold always use cadmium free gold solder.  For health reasons, this is the only solder you should be using anyway.  However, for platinum it is especially important.  Cadmium can migrate into the grain structure and cause brittleness.

Before joining platinum and gold together ALWAYS finish and polish the platinum piece.  Platinum requires a longer polishing time than gold.  If they are polished after joining the gold would wear away before a final polish could be applied to the platinum.  As platinum does not oxidize when heated, the polished finish will remain after soldering.

~ Brad

Platinum Jewelry,Fabrication,Casting

Soldering Gold & Platinum

When soldering gold and platinum together make certain to anneal both parts thoroughly before soldering.  These metals expand at different rates when heated.  If not thoroughly annealed stress tears may develop as the metal cools.  In addition, allow the metal to cool slowly after soldering.  Do Not quench the hot metals, rapid cooling increases the stress in the metals.

- Brad

Platinum Jewelry Fabrication,Soldering Gold & Platinum

950/50 Platinum /Cobalt Alloy

Platinum in its pure form is very soft and needs to be alloyed.  These Platinum alloys have different advantages and are used for specific purposes.  The flow properties of the 950/50 Platinum /Cobalt mixtures are best suited for casting.  With this alloy, very fine pieces of excellent quality can be cast, and considerable detail can be achieved.  Pt/Co has an annealed hardness (HV) of 130 and when cold-worked achieves a hardness (HV) of 270.  It polishes well and holds its luster for a long time.  When welded with a torch Pt/Co may oxidize slightly.  This can be removed by firecoating the object after the initial welding and re-heating it to about 1000° F. Pickle in a 10% solution of nitric acid.  The oxidation will not reappear during wear.  It is not possible to torch-weld different Pt alloys together as they have different melting points.  It is always safe to solder them together using 1500 or 1700 solder.  As a point of interest, Pt/Co is slightly magnetic.

Be sure to wear #5 or #6 welding goggles to protect your eyes.

Platinum /Cobalt alloy is slightly ferro-magnetic.  This Pt950 alloy has very good flow characteristics and is a superior platinum casting alloy.  With its good hardness, it takes on a great polish.  The best way to size a Platinum /Cobalt alloy ring is soldering with 1700 solder.  Roll the solder paper-thin, wedge it into a very well fitting seam and heat.  The seam should be very, very thin.  Now use a file to remove excess solder, and BURNISH the seam with a Tungsten burnisher.  This should remove all traces of the seam.  Now polish and clean the ring.

Jurgen

Platinum Alloys,Platinum Jewelry,Casting Platinum,Welding Platinum