Using a G-TEC Torch Booster you can get excellent results casting
platinum and gold with high pressure natural gas.
In 2011 I demonstrated this at the Stuller Bench Jeweler Workshop
and they made a video that is posted on their benchjeweler.com
website here: http://www.ganoksin.com/gnkurl/ep7zr5 (click play to get
the video started).
In the video I melt a bronze nugget - when I do this demonstration I
always ask if someone has a piece of jewelry they would be willing to
donate but everyone declines, although once a man handed me a gold
tooth so we melted it!
You can see how the flame looks and that the metal melts quickly.
Now platinum needs to reach 3,300F to melt but natural gas reaches
that temperature easily.
A few years ago we did a 3 minute testimonial video with Bob
Pampillonia of Pampillonia Designs in the Dallas area - he switched
to natural gas after using propane and you can see that video on
YouTube here: http://www.ganoksin.com/gnkurl/ep7zr6
G-TEC Natural Gas Systems