The May edition of From the Bench provides you a whole host of resources about platinum. We decided to take it a step further by consulting Stuller experts Randy Welch and Shane Guidry. Together, they answer the most frequently asked questions we get about platinum.
1. What are safety concerns in working with platinum?
b. Because acetylene has a high carbon content that causes contamination in platinum, its use is not recommended. Use a hydroflux torch, natural, or propane fuel.
c. Use tools solely for platinum
d. Use ceramic solder pads. Charcoal (carbon) will contaminate platinum. Use ceramic tweezers, tungsten picks, tungsten burnisher, agate burnisher
e. Use separate bench pins
f. Steel tweezers will contaminate platinum and will leave black spots.
2. Is it necessary to burnish platinum after sanding?
We recommend burnishing after tumbling and prior to prep and polish processing by using Chicago pneumatic air hammer or agate burnishers. We burnish in the areas on the inside bottom sprue location and inside the ring, lap surface and outer surface at 11:00 am and 1:00 pm location of the shank area.
3. What’s the best way to clean heavy oxidation on platinum and metal of choice?
Ruthenium and Iridium Platinum have minimal oxidation in the fusing/soldering process therefore it will be removed in the polishing process. For Platinum Cobalt – used by many manufacturers for casted pieces because platinum cobalt is dense with less porosity and is longer lasting. The surfaces are smoother than platinum iridium and ruthenium immediately after casting. Gives a better success rate than other platinum alloys. Cobalt is ferromagnetic so keep it away from magnetic bench shavings. Because PtCo (5%) is ferromagnetic, a magnet can be used to determine if a jewelry item is made from PtCo (5%). Clean slight oxidation with a pencil eraser. For heavier oxidation dip it in a boric / alcohol (denatured) solution, heat to 1200°F or slight red color, dip it in pickle, and then neutralize with baking soda.
4. I’m just getting into platinum work. Which tools will I need, at a minimum, to start?
a. Ceramic solder padsb. Ceramic tweezers
c. Tungsten picks
d. Tungsten burnishers
e. Agate burnishers
f. Protective eye wear
g. Polishing compounds
h. Tapered ring buff
i. Muslin buff
j. Lap wheel
k. 360-400-500 abrasive paper
l. Solder
5. Are there certain stones I should absolutely remove from platinum before welding?
All stones should be removed when welding or soldering with platinum solder on a platinum ring. A few tips and tricks: You may use 14kw gold solder cadmium free, to re-tip prongs around certain colored stones and diamonds. Simply flatten surface of prong that you want to re-tip using a small file. Add 14 kw solder, flatten surface again leaving a little solder, clean well then heat area to attach platinum wire representing prong tip, clip excess then prep and polish prong.