Originally published in the MJSA Journal, At The Bench, Quality Craftsmanship 8/07

Week after week, everyday items helped save the day on the old "MacGyver" TV show. This month MJSA Journal offers another in a series of articles on common household or found items that can also be put to uncommon use: working on jewelry.

Soldering a small faceted stone or cabochon to metal can be tricky. Overheating can discolor, crack, or even fry many gemstones if you aren't careful to protect their delicate crystal structures. Foam-based products will protect the stones from heat, but they are messy and time-consuming come cleanup time. Instead of frying your gemstone, try frying a potato. Although tasty when fried, a raw potato is a cool and biodegradable heat sink for your precious bling.

In this example, a red faceted 3mm quartz--which is very susceptible to color changes with the slightest changes of heat--has been mounted into sterling sliver tubing and friction-fit into a half-round band.

To create the heat sink for soldering, halve a cold potato (it should sit in the fridge for at least two hours prior to use.) Remove the tube setting and make a "potato plug" by pushing it into the potato and shearing it at the end.

Dig out a depression and nestle the ring in it.

Solder the setup from beneath. Some steam will emanate from the potato as you cook it. It's important to heat quickly; I used medium solder with a #5 oxygen/fuel tip.

As you can see, the setting is soldered beautifully...

...and the stone is still red. (You can use an ultrasonic to clean leftover potato out of the setting.