Help: white gold ring prongs break

[pkfin]

Hi,

I am a novice maker, but decided to take on an ambitious project of making an engagement ring for my girlfriend. 4-prong solitaire setting that would hold a 1 carat stone.

I started with making the ring shank out of silver. I tried to make the prongs as well, but it turned out to be too challenging at this point with not so much experience. Simply put, I was not happy, the few versions I did were not close to the quality I want to give to her.

So, I decided to model the prong part in 3D, print it in wax and cast in metal (used Shapeways for this). Then I soldered the parts together and finished the ring. I know professionals would never do that, but unfortunately I don’t have years of time to practice at the moment. Wish I had

Anyhow, I did the first versions of the ring from silver, and then tested them out by setting the stone. I actually had a model of the stone 3d printed in plastic, so that I could test stone setting safely. Silver versions worked fine, and I was able to gently bend the prongs over the “stone” nicely.

However, when I had the same design prongs printed in white gold, the prongs broke a bit below the tip when I was bending the tip over the stone. Well, I thought maybe the prongs were too thin and redesigned the prongs for the next version. Again, I had it printed out in white gold, and exactly the same occurred again, even though I had strenghtened them quite substantially. A few of these failures caused my proposal to be pushed back, and I had to pull the plug on my plans.

I am starting to think that the cast white gold from is too brittle for ring prongs, and I am having trouble deciding what to do next.

As experts, what do you recommend? Change alloy or something else? Or is my only option to just go down the long path and keep on practising prong-making from solid stuff until I get it how I want?

[bvwjewelers]

Could you put up some photos?

[ErichCDesigns1]

Shooting from the hip, I’m going to say that the alloy was too brittle. White gold alloys are typically done with nickel (though I’ll only use palladium). The nickel makes the alloy hard and brittle making it just a frustrating mess to work with. Early on, I remember doing a white gold ring (cast) for a friend and it broke in half just trying to size it. I’d try switching to a palladium-based white gold alloy or platinum. . . Something that’s not so brittle, but this isn’t exactly my area of expertise

Good luck!

Erich C Shoemaker

[pkfin]

Hi,

and thanks for the replies already!

Erich, the 14k white gold alloy I used had 58% Gold, 24% Copper, 9% Zinc, and 9% Nickel. I would have an option of course to go with platinum (95% Platinum, 5% Ruthenium) but the soldering of course will be a bit trickier. I googled the issue of platinum prongs vs white gold prongs and ended up on sites that said platinum to be harder and more brittle, which to me was a surprise. I thought that platinum would be more malleable and flexible, but I guess that depends on what white gold alloy you compare it with…

Here’s a few photos as well. The lightest ring is the silver one with the successful plastic stone setting. The white gold one without a “stone” is the first white gold version. Only two prongs broke when setting the stone, but then I experimented with the flexibility of the other two just to find out they were brittle as well. The other white gold one (with a “stone”) is the second (and so far last) version with strenghtened prongs. But that broke a prong as well when setting the stone. The prongs were so much stronger on that one that I actually had to use a jewellers saw to cut the base of one of the prongs to get the real stone out without doing any damage.

Thanks for the help! Much appreciated.

[Richard_Hart3]

Solution for brittle white gold, David Fell refiners
has a alloy, Winter White that is malleable and
you can forge it and no cracking.
Cast or fabricated…
Made a lot of these rings with it.
[image1.jpeg]

[WADEDESIGNS1]

If you really want to make the head you should fabricate it not cast it. Seems to me you are re-inventing the wheel. There are many supply houses that will sell you a die struck 4 prong head like that for around $15 in 14k white gold. There are many custom designers on here like me and I bet most of us would order that part. I just looked one up in Stuller and my cost is $14.58.
No platinum is not more brittle than white gold. Platinum prongs do bend easier but wear away slower. I don’t like to use platinum for a prong setting. But I love it for a bezel or a bead and bright cut.

[shanaithal]

Erich,
Most nickel white gold alloys when slowly cooled tend to become harder. For example, a nickel white gold ring could have become hard if the flask was allowed to air cool after casting. In such a situation the cast ring can be softened by coating with boric+alcohol mixture and reheating to a dull red and quickly quenching in water or pickle solution. The prongs become more forgiving allowing you to manipulate them better during stone setting.
So what I’m saying is that nickel white gold alloys can be made softer by suitable heat treatment.
I do agree with your statement that palladium white gold alloys are relatively softer than nickel white golds. And most palladium white golds do not harden when they are air cooled from a high temperature.

Shan

[mpandfamily]

You might consider sending your models out for casting. Or ask a local shop if you can come in and cast with their help. There are so many variables involved in casting that your poor results may be hard to identify without an experienced person looking over your shoulder. That said, a weird thing about casting is there is not one single road to success. Some people get consistently excellent results using pretty unorthodox methods. In your case, you just need one good casting and a casting house will give you that. You still made the ring, just jobbed out one step.

As far as platinum goes. It’s an unusual metal with contradictory properties. It is not brittle when properly cast or fabricated. Platinum is naturally white while white gold has a bit of a yellow cast and so is almost always rhodium plated, that’s a positive for platinum. It does dent and bend more than white gold, which is a negative, but it wears away much more slowly, a positive. In fact it often doesn’t really wear away but sort of shmears, which is unusual. White gold wears away, but not as fast as silver. So the contradiction with platinum is that it’s somewhat soft but wears away slowly. Casting it is more difficult than white gold. It requires gates of hell temperatures and different investment and crucibles, and usually a hydrogen oxygen torch. Again platinum has contradictory properties, when casting you have to get it up to 3400F, that is incredibly hot and over 1000F hotter than 14K white, yet once you remove the torch it freezes up almost instantaneously (compared to how long gold stays molten). It’s a interesting metal. Challenging yet wonderful to work with.
Mark

[ErichCDesigns1]

Thanks for that bit of info! It’s been so long since I’ve worked with standard 14KW & 14KY alloys, I’ve nearly forgotten “how” to work with them at this point. That’s kind of depressing now that I think about it. . .

[pkfin]

Hi all,

and thanks a million for the contributions! You know this stuff, no doubt about it

Wadedesigns is right, I am trying to reinvent the wheel. I the beginning of this project, I actually ordered ready made prong heads from Cookson Gold (UK-based), but I just was not pleased with the designs at all and sort of disappointed when they arrived. So, I decided to do it on my own. However, now that I googled Stuller I found out that they have way more designs than can be used as such or altered. Thanks a lot for that tip!

I guess die-struck is what I should aim for, right? Metal mold is cast, so it might present same issues I have had so far. How about the prong heads that don’t say they are die-struck or metal mold? How are they fabricated?

I already found a few options, for example, this one is quite close to what I had designed:
https://www.stuller.com/products/24060/2296119/?groupId=85815&recommendationSource=SiteSearch

Any other good US based webstores with wide variety of prong heads you could recoomend to check out? I live in Finland so the only requirement is that they ship here

The casting is unfortunately not a good option. Even though I live in Finlands capital, there’s not really casting houses that cast one-off items for customers, I have been trying to find one, but no luck so far.

Also, one more question about soldering: I have a feeling that the 14k white gold I have been using seems to catch a slight dark grey hue during soldering. I was able to see it clearly when I compared the Shapeways casted prong part (which was shiny and nice) to the shank I had already soldered once to join it to a ring. When I soldered the prong and the shank together, the shiny prong also seemed to catch the same grey hue.

I clean the parts thoroughly before soldering and applied a generous coating of borax as well. The borax, however, seemed to sort of burn off during soldering, but shouldn’t that be normal? Any ideas why the alloy darkens a bit? Is it something to do with my torch or the heat of the flame? Do I torch the piece too long/too short time? Anything I can do better? Or I bet a lot, but the most obvious things… Or should I just settle with having it rhodium-plated after the whole ring is finished?

Thanks a million again for your help!

//Panu

[vladimirfrater]

Hi Panu,
im Ted, in the UK, and have followed your problems/topic,
as you know, metal work in this trade is done either fabricated, cast or wrought, . I only make my work by the wrought path, so the metallurgy of my metals is paramount.
There is only one metal in my w/shop thats cast and brittle! and thats in the heavy machine tool frames I use.!!
So to discuss wrought, as in die struck mounts, .
There all made from ductile sheet metal, blanked with simple punch and die tooling into the snowflake or star pattern, then progressively upset in cone steel dies. That includes the prongs.
Makers like Cookson gold who I buy from and Stuller, all make them this way, as

1. Its the cheapest,
2. the most reliable
3. the same steel dies can be used for the different sizes.
4. in what ever metal they think the customer wants.
5. the fastest.
   You too could do this quite simply,
   saw out the shape, make up some steel cone positive shapes with access to a lathe and just hammer the shapes into the concave cone die to form the cone shaped mount. Mild steel will be quite good enough. no need to harden, nice tho! Your first tooling?
   thats all the manufacturers do.
   Most of my work is done with press tooling, dies, including minting 3D coins and plaqus with production runs up to 2500 off…
   When buying mounts for the very first time, always buy 2, why? you can experiment to get the feel of the prongs, to the destruction point, so you will know just how far you cannot go! before it breaks!.
   As wade designs has written, your seriously out of pocket in time and expenditure on this project.
   Jut buy in the settings and get on with earning you daily living.
   finally, dont rhodium plate, It looks good to start with then is poor after time.
   Up date us how you solve this one.
   Ted.

[andy_c]

Yes!!! I pour and forge ingots from 14k Winter White often. Rarely if ever a problem. I do Quench nickel whites in alcohol once it’s cooled to black heat.

Please excuse any typos-- curse my clumsy digits…

[mpandfamily]

The quenching conversation is interesting. I was taught to never quench nickel white gold because that can cause it to become brittle. Also to not let a cast flask of nickel white cool much beyond a red hot button, which seems contradictory. The flask advice had something to do with the insulating properties of the investment, that you wait until the button is no longer red in a dark room but quench while still hot. Old timers trained me 40 years ago. I never have any brittleness issues. But alloys have changed.
Mark

[andy_c]

That’s why I quench in denatured. Soft and gentle.

Please excuse any typos-- curse my clumsy digits…

[mpandfamily]

They guy who I apprenticed to was a master goldsmith who had apprenticed in Pforzhiem Germany. So he had a very formal German education in the art of jewelry making and it was a pretty large scale facility . I remember him also saying that they quenched large sheets of gold in alcohol. My concern was igniting the alcohol, he said they had a lid they’d drop on it right away just in case. I’ve never done it. It’s sorta spooky.

[pkfin]

Thanks again for the contributions!

I have now set my mind into finding a die-struck readymade mount and then just tweak it to my liking (if needed) and solder it onto the ring shank. Good thing is that I already have the shanks, I just need to take out the broken mounts and replace them with a new one.

There’s a few issues with finding the mount, though. Do you have any experience from European webshops that have a good selection of mounts? I haven’t found anything even remotely close to Stuller. Cookson does not have nice mounts. Stuller, unfortunately only sells to established businesses, and that’s of course an issue for me…

I will promise to keep you updated on the progress with this project

[andy_c]

By quenching at “black heat” (no red glow) the Chan Eid igniting the alcohol is very low. At the temp of around 600-800 I think that the stresses of higher heat quenching are mitigated and the benefits are maximized.

Please excuse any typos-- curse my clumsy digits…

[arkaysilversmiths]

Which part number are you looking at? I was looking at 411:91:S for a one carat (6.5 mm) round stone for comparison. My cost was not as good as yours if they are the same.

[WADEDESIGNS1]

My cost on that one is $21

[pkfin]

Hi all,

finally got the ring finished. Ordered a die-struck readymade mount from Rio Grande and then tweaked it to my liking, and soldered onto the ring shank. Worked out nicely.

I was quite confident that the prongs won’t break this time, but ended up taking the ring to a professional goldsmith for stone setting. I wanted to de-risk it, since if I would have broken the prongs once again, I would have had to cancel proposal plans on our upcoming trip to Mexico. I would not have had time to re-do everything.

Goldsmith set the stone and said it went really well. I took a few photos from the before and after stone setting, and have to say I am really satisfied with the outcome

Thanks again for the tips! Now there’s only popping the question left…! !
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