If your intention is to create pieces for the purpose of selling, then I recommend avoiding heat treating gemstones by firing them with your metal clay. The reason for this is detailed in this article. In order to achieve a high quality jewelry creation, adding soldering to your skill-set is essential. Investing the hours of hand-forming of metal clay, the selection of the most beautiful gemstone deserves the highest quality result in my opinion.
Let's take a look at some stone setting techniques that avoid firing the gemstone. These methods offer the capacity to bezel set natural cabochon gemstones. Faceted gemstones can also be accommodated using these methods.
Embedding Bezel Wire
Yes, you can embed a bezel wire pre-firing. This entails:
Cut and form a piece of bezel wire to fit 1mm larger than your stone. A bezel larger than 1mm than the stone can lead to a real challenge to set the stone evenly or cause the stone to be loose.
Embed the bezel at least 2mm into the metal clay base.
Apply thick slip to the bezel wire connection.
Apply slip to around the inside and outside of the base of the bezel wire.
Refine and smooth the dried slip to any uneven surfaces.
Fire using your normal firing schedule.
Clean, Patina and polish your fired piece.
Insert your stone and using a bezel pusher tool, secure in place.
Risk of inconsistent results based on different shrinkage rates of clays.
Resulting bezel may deform and require having to adjust the stone sizing which requires lapidary skills.
May cause the metal clay base to form cracks during firing.
Optional: Use embeddable prong settings. these work pretty well and have minimal negative impact on firing, when using fine silver.
For these reasons, I don't feel the inconsistency is worth the high risk of losing the dedicated creative time in creating complex designs or hand-forming the piece. As fine silver is the better option for this method (details below), experimenting can be quite expensive. Then again, success can be very rewarding.
Two-Step Firing A Bezel Wire Bezel or Pre-Fabricated Prong
To avoid the potential of your bezel being deformed by the metal clay shrinkage, you can attach a bezel to your fired metal clay piece. This entails:
Determine the space for the gemstone in your original design.
Create and fire the piece until fully sintered.
Cut and form a piece of bezel wire of the same metal as your creation to fit your stone. Ideally, fine silver is your best choice of bezel wire. This will avoid potential issues caused by the oxidization of alloy metals during firing.
Attach the bezel to the base using a fairly thick slip. Apply slip also to the wire connection joint. Adding a snake around the outside at the base will add strength as a decorative element. Just make sure to calculate this in step 1.
Wrap a piece of wire (same or higher melting point than the metal of your piece) to hold the bezel in it's position.
Fire at the same firing schedule as the piece.
May require multiple firings if the slip contained air bubbles or did not cover the entire bezel wire base.
Bezel may move from its intended position if not fully secured.
May require additional metal-work to remove any excess slip that fired into metal on the inside of the bezel.
Although a good result can be accomplished using this method, I don't see additional benefits when compared to soldering. The potential excess time, the additional costs and the complications of correcting any issues arising during firing make this method a good option for those looking to set the occasional stone.
Replacing the step 3 of the above method with a bezel cup that fits the size of your stone.
Can be really challenging to find a pre-fabricated bezel cup to fit your stone.
Limited to available bezel cup shapes.
Although fine silver is the better option, sterling silver (or base metals) can be problematic due to the oxidization of the metal during the re-firing process. Any oxidization will compromise the connection, even if not visible.
Jewelers Grade Soldering Bezel Setting
By far my preferred method is soldering. When compared to the previous methods, soldering a stone setting has many advantages and benefits. These include:
No limitations on the stone size or shape.
Precise positioning and fit for the stone.
No shrinkage impact.
Versatility allowing for more creative settings.
Secure and lasting connection befitting valuable gemstones and creations.
Many are intimidated by the prospect of soldering. In reality, once mastered most wonder why they waited so long to add this essential skill.
For those with a preference for self-guided learning, our soldering tutorials not only provide in-depth step by step instructions, but also cover the pit-falls, corrective methods and tool options. For a complete guide of all the soldering options try: Sky Guide 6 & 7 package.