What a beautiful Design...you say

By Jurgen J. Maerz

 

What a beautiful design, you might say.  You look at the rendering.  The ring is a modern two tone design.  The top of the shank splits into two yellow prongs that are complimented by two white prongs coming from the other side.  They will hold a single stone.  The shank flairs and is divided into the two different metals.  The designer has put a lot of effort into this design and you immediately like the flow of the ring.  You sit back in your chair and study the design and are trying to figure the best way to make this.  The ring will be made of platinum and 18K.  You always liked this combination.  The great whiteness, strengths and shine of the platinum, together with the warmth and glow of 18 karat gold.  What a combination!  And, if you play your cards right, it will be a design that can be sold in fairly decent quantities at the stores you have been dealing with for years to come.

So you create the model.  It is exciting to see the pieces fit together.  The two parts that are to be cast in platinum and gold will be joined together to make this great ring and they fit.  The sleek lines of the shank, the way the prongs meet to hold a stone, the very design all combine to create the perfect piece.  You are pleased with yourself.  You select a spot for the sprue on each of the two halves and vulcanize the pieces into a rubber mold.  After cutting the mold and injecting the wax, you cast 3 of each of the waxes in platinum and 3 in gold.  

Finishing the platinum took a little more time than the gold, as you need to reduce the scratches in platinum through several steps.  Platinum’s hardness and toughness requires polishing compounds made especially for platinum.  But the shine and luster created is very rewarding.  You realize that completely finishing the platinum would help you later, as gold polishes faster and one tends to over- polish gold once it is joined to the platinum.

You solder the platinum and gold sections together.  You are satisfied with your soldering job and take a closer look at the seams.  Your heart skips a beat!  Your eyes won’t believe it, but there it was: Along the seam there are fine cracks in the platinum.  Oh no!  You scream inside, a closer look reveals cracking along the entire seam.  Stress!  You must relieve the stress.  The platinum expands at a different rate from the gold and because the solder is already in place, the piece is cracking and warping. 

You solder another set together and try to place it in a preheated kiln to relieve the stress.  After 30 minutes at 700 C it should be just as new.  You turn off the kiln and let the piece cool inside.  As you take it out, you look at it and smile.  It looks good!  You finish the piece and there they are again.  Cracks!  And the trouble is, they don’t show up until you are almost done finishing.  There is no way to burnish, no good way to fill.  You want to tear your hair out.  You sit back, look at the design and think.  What to do - WHAT-TO-DO???
Suddenly you jump out of your chair.  You just had the greatest idea since the invention of sliced bread.  Cast the gold onto the platinum….and why not?  Nothing is going to hurt the platinum. 

 

What a Beautiful Design continued