Arc welding with stones in place


I have a natural alexandrite set in an 18k engagement ring I’m making for my partner (yay!) and I’m almost finished. Unfortunately, as I was doing some final adjustments to prong position, one of them snapped off.

I have a sunstone arc welder that I’ve used for some repairs as I’ve been building the piece, but I’m TERRIFIED of damaging the stone if I try to add metal to the base of the missing prong. Is this a job for a laser welder? Or a non negotiable stone removal kind of situation? Any advice at all would be deeply appreciated.

For some context I’m an entirely self-taught hobbyist. No formal training beyond YouTube videos and occasional tips from other folks I’ve met along the way, with a completely different job that allows me to pick up the tools I need to do this kind of work casually. I’ve been at it about 14 years and I consider myself pretty experienced but obviously there are HUGE gaps in my training and comfort. The arc welder is a recent purchase and one argument for it was the potential for repairs that don’t require removing stones, but this particular stone is one i really don’t want to damage.

Time to admit defeat and contact a professional? I’m really proud of having built this piece entirely myself without training so it’s a hard pill to swallow…


Great question. I just wanted to welcome you and I look forward to the wisdom of the sages that will follow…

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…was the ring a cast piece…?…if so, cast prongs can be less strong than fabricated prongs…something to note for future reference…

…the prong snapping off may have been due to some unforeseen metal structure weakness resulting from the cast…and not an error on your part…

with that said, it is a beautiful ring and you should be very proud of it!

if you are not yet comfortable doing this type of repair with your new welder, reaching out to a jeweler with experience in this type of repair would be my suggestion.

then, you can practice this type of repair and become proficient with your welder without the worry of further damaging your beautiful piece!…




I wouldn’t call it a defeat at all! This is an amazing accomplishment for someone who is self-taught! Huge congratulations. You should be very proud of yourself. Also it sounds like you’re getting engaged right? Huge congratulations on that too!!

But yes, it’s time to ask for professional help. I’ve do a lot of welding both precision tig welder (with Orion and PUK) and laser welding (with a LaserStar welder). A laser welder is a better choice for this kind of repair. It’s not that you can’t do it with your Orion welder, but a laser welder will be safer and easier.

Take it to a professional jewelry store that specializes in jewelry repairs and has a laser welder.

Now in all honesty, whoever does this repair will have to analyze this issue in person. They may decide that the best path is to pull the alexandrite. Then assuming that your side stones are diamonds, they may decide the best way to repair it is to grind out the damaged prong a little and solder in a new prong instead of welding one. Based on the images, if I was doing this repair, that’s what I might do. But the final decision would happen after see the ring in person.

Whatever path the repair jeweler takes, it’s a fairly common repair. With any luck, they might let you watch, so you’ll know how to do it if it happens again.

Congratulations on all fronts!!



Not cast, fabricated. I constructed the basket from self drawn wire. The goal was a “grain to finished” piece where I make everything from scratch. I was pretty ambitious here, but it has been such a fun project!

As I was working on the body of the piece I think I bent the prong wires a few times. Mid way through the diamond setting I bent a prong once too many times and it snapped. I was able to arc weld it back with the diamonds in place and didn’t damage them. But it snapped again as I prepared the setting for the alexandrite. I arc welded a few beads onto the snapped prong and got it bent over the stone and shaped up before I decided I didn’t like it being uneven and tried to adjust… snapped a third time. This time the alexandrite is present. Oof.

It sounds like the consensus is to go to a professional here. Anyone have a recommendation for a receptive jeweler in NJ who might let me watch the repair?:grin:

For those interested I can post a few more pictures of the construction process. It’s been a blast!


Starting material:

Sheet rolled and design sketched:

Cut and formed:

Wire making, bar pour:

Wire making, all finished, ring base formed:

Ring base cut and shaped:

Basket formed and fitted (soldering is in my last post)

Stone settings drilled:

Side sapphire bezel forming and fitting:

Polished and prepped for diamond setting:

Diamond setting:

Sapphire setting:

And you’ve seen the rest! Been itching to tackle gold and this is my excuse. Up until about 6 months ago, I only had worked in silver and copper. Much lower stakes!


oh riiight! i remember these pics!

perhaps you didnt have enough penetration thru the weld…


I tried going around the diameter of the prong, but I’m new to the welder so I probably missed something or didn’t run hot enough for penetration.

It sounds from your earlier comment like alexandrite might actually be capable of being near the weld point-do you have experience there? I was playing earlier today with a synthetic one and I can get right up next to it with the electrode arcing and it didn’t seem like it damaged anything… I’m just very nervous about the real deal. It’s an investment!

Now that you’ve shared this with us, I actually think that you probably have the skills to repair this yourself. After all that you’ve done to make this ring repairing the broken prong should be comparatively easy. But I think this is going to be a soldering operation, not an arc welding operation.

I’ve heard lots of varied explanations, but welded metal is more brittle than soldered metal. Welded prongs are fine if you don’t ever have to bend them, but not great if bending is required. Also because your prong is completely broken off, you’re probably not going to get full weld penetration through the entire prong wire, so it will always be weak.

If you want to try to repair it yourself, I think your best bet is to carefully lift up one prong and to remove the alexandrite. Then drill or grind down a little on the broken prong like you did when you fabricated the ring. Coat your entire ring with a thin paste of boric acid and alcohol (be sure to burn off the alcohol before taking a torch to your ring) or boric acid and water (to protect the diamonds while soldering). Solder in a new wire to create a brand new prong. Before you set the stone look at the prong that you lifted up under magnification and look for any hints of stress fractures. If you see any hint of cracks or fractures on any of the prongs, solder those closed.

Carefully grind a new seat in the new prong. You may have to slightly lift the other two prongs to get the stone back into the setting. Then carefully set the alexandrite.

One thing that I often say is that you can bend a prong once and it probably won’t break. If you’re lucky you can bend it twice. On the third bend there’s a good chance it will break. On the fourth bend it will probably break. This means don’t bend the prongs up and down over and over to make everything be perfect. The prongs will almost certainly break and you’ll have to start all over again.

Again, if you don’t feel confident, take it to a jeweler who does repair. This is a pretty standard repair.

I tried to find some YouTube videos out there showing this, but I didn’t see any good ones.

Sorry! I don’t know anyone in NJ who does repair, but maybe someone else in the forum does.

Good luck and let us know how it turns out!



Hi Jeff,

Thank you for all the careful thought here! Also thank you for your kind comments and praise for my work earlier - means a lot to this hobbiest!

I think I could pull the stone, carefully. Bit nervous about cracking things with the stone underneath, but maybe time to invest in prong pulling pliers? But once I do so, I have all these diamonds around the prongs that I can’t protect. I have the smith micro torch so I can definitely deliver pretty tight heat, and I’ve even replaced a prong on another piece in a similar way (drill and insert and solder) but the diamonds are RIGHT THERE. Not to mention the sapphires. Is it still a feasible solder operation? I could also imagine a careful arc weld to seal it back in…but my luck there has been hilarious :joy:.

If I go for it I’ll definitely update folks here…

I’m no help but I just want to say how very impressed I am with your work, for being self taught. That ring is amazing and beautiful! I too am a hobbyist but I’ve taken quite a few classes and workshops. I wouldn’t attempt anything that advanced yet. I hope the repair comes out perfect, whatever you decide to do. Congrats on the ring and your engagement.

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Thank you! I’ve been dabbling in this since my father gave me a few old silver quarters and a plumber’s propane torch in high school! :joy::joy::joy:

After I got my degree (chemistry!) and started working I rented local studio time to try out all the tools I wanted and started building up my bench at home. It’s been a journey!


Hey JeffG, Daniel and All,
I am in awe of this kind of patience and skill! Nice ring, Daniel!

Just trying to learn here, so forgive me if I ask some questions of my betters…so the problem of the prong breaking off comes possibly because the prongs were welded on, rather than soldered in? Or the prong wire had some porosity in it? Or no way to know?

As far as your bend it once, bend it twice, don’t bend it three times rule, Jeff, would that apply even if you annealed the prong completely (which one might not want to do in this particular situation)?

My recollection about heat and diamonds and sapphire is that, in most cases, they will both take the heat of a soldering torch, but they have to be scrupulously clean or the facet surfaces could burn and need repolishing. Is that right, Jeff? And, in rare cases, there could be a pre-existing fracture or large gas bubble in a stone that would burst and cause major damage, but that should be visible on examination with a gemological microscope. Is this also right?

Thanks so much, Daniel, for showing the photos of your fabrication! Inspires me to try something new. And thanks to you, Jeff, for your very cogent explanation of prongs and soldering, etc.

My last comment on this…with such high end stuff, would some use Firescoff instead of just boric acid and water? Thanks! -royjohn


Only gonna attempt to answer your first question here, the latter two are ones I’d love to hear others pitch in on!

the prongs were soldered on as wire that I drew from bar stock. It’s unlikely the porosity was there to start given the fact that it survived the stress of the draw plate. But when one broke after the diamonds went in I chose to weld it back on rather than solder (was worried about those diamonds and sapphires!). It looks like this weld had some porosity (I think I can even see internal bubbles on the scope) after I repaired it. It lasted well enough to be bent over the stone initially but it lacked the ductility to be adjusted after doing so, and snapped.

Do you have experience soldering with diamond and sapphire in place? I’ve never tried it, but my training is spotty at best. I think I may also pick up some of that firescoff you mentioned here to play with… Even if it’s not the solution here, it sounds very intriguing.

When you use a pulse arc welder, the connection needs to be a perfect join. If it has thickness, it is best to think of a “V” to be filled, something like sizing a ring. Also, you need to know the penetration of your weld - can it penetrate the entire thickness of the prong… and not to forget that there is always sacrificial metal involved. If the outer surface looks smooth and the metal is thick, the sacrificial metal may well have come from inside the wire.
If it were my problem, I’d fool with a piece of wire that you used to make the prong and figure out how to set my machine to make a safe and secure weld. Setting the breadth and depth of the weld is critical as you have discovered.
When working with such a valuable stone, aim the electrode away from the stone to avoid hitting it with a charge. You can aim right, left and from the top, away to the outside. It will definitely take several shots.
Judy H


This was my initial thought for the solution. But I’m pretty nervous about that stone. It’s by far the most expensive part of the piece (alexandrite is CRAZY) and I’m leaning towards a full removal and replacement at this point. The risk of damage feels too high to stomach.

I definitely need more practice on the arc welder. It saved me a few times on this piece, but I think it’s easy to think of it like soldering and they’re very different beasts. The fact that it pulls metal towards the weld is super risky if you aren’t careful!

Diamonds, especially smaller ones are still okay to heat up to soldering temps, but pre-coating with boric acid is still necessary. I don’t know about Firescoff? I’ve hardly ever used that product.

One of the reasons that prongs break with repeated bending back and forth is because the process of cutting a seat is to similar scoring and bending. You not only create a seat, you also create a bend point. Annealing would help the prong not break, but not always.

With the alexandrite out of the setting then Daniel can solder a brand new prong wire similar to how the ring was originally fabricated.

I used to heat up sapphires in repair work, but I’ve been told that these days they can be irradiated and that heating up can destroy the color. So I don’t heat sapphires anymore. Just diamonds.

For lifting up prongs, this is one of my favorite tools.

Hope all this helps!



I’ll probably have to risk these sapphires. They’re not gonna be easy to remove and they were a royal pain to get set. I have more available if I destroy them, and more diamonds. Only one alexandrite though.

Ok, I think I’ll give the resolder a shot. I have firescoff on order and it seems like it’ll function similar to boric acid. And I have boric acid already. We’ll see how this goes. I’m tempted to just resolder all four prongs…

What’s the worst that can happen, right? I made it once, I can make it all again :grin:.

The real thing is getting out that center stone safely. I’m tempted to just saw cut the prongs and avoid any torque on the alexandrite. It means replacing all of them, but it may be worth avoiding the risk of putting too much force on the stone…

Also got to do this without a certain someone noticing all the extra time in the studio… :joy::joy::joy:

Hi DanielH,
I don’t have any experience soldering around diamonds and corundum, but, as some have said, production bench jewelers do it all the time, with proper precautions. I looked for info on Google and found a discussion on our own Ganoksin forum from ‘07 that explained a lot about this topic. The title of the thread is “Soldering with diamonds in place” and it begins with a query from Joan9632. If I were you, I’d read the whole thread, because it is fascinating and it would take too long to summarize here. A few details from the thread you will need to know…yes, using the boric acid protective coating on the diamonds is necessary, but if you put it on the sapphires it is going to etch their surface. So you might use kool jool or siliquar or even wet paper towel to protect the stones and go in fast and hard with the solder, but don’t take my word for it, read the thread and consult with someone who knows this stuff in practice. And if any of the stones have big fractures or are glass filled, you could come to grief, even tho’ this is not likely if you chose decent stones, which I’m guessing you did.

As far as whether Firescoff would work as a diamond protectant like boric acid does, IDK, but Rio Grande’s tech people could probably tell you. It is touted as a great barrier flux, supposedly better than boric acid, while also being a very good soldering flux. It’s expensive compared to boric acid, but then, if you are making high end gold stuff, the cost is small compared to what you are spending on gold, melee diamonds, sapphires and a natural alex with a very nice color change.

I’m going to suggest another thing which I don’t have firsthand experience with, but which I have read about. If no other approach works for you and you don’t want to seek out a master jeweler to do the soldering, you could consider replacing the prong via cold connection. You could drill a hole behind the prong where it has broken off, file a piece of wire to use as a replacement prong and rivet the wire in place from the back of the ring. You could also tap the hole in the ring and put a corresponding thread on your wire, screw the two together, cut off the back end of the prong and peen over the end like a rivet on the ring’s back side. Since gold is expensive, you could solder an appropriately sized and shaped piece of silver onto the top end of the prong with gold solder so that you would have something to grab to turn your prong to screw it in…then just saw off the silver and shape the prong as needed.

Now this cold connection protocol is just something out of my fevered brain, so others here on the forum would have to tell you whether this would work…I do have a set of miniature taps and dies for work in silver and gold and they are cheap to buy and I assume they are pretty easy to use.

Good luck whatever you do and I hope you will return to this forum to finish the story of your amazing ring! -royjohn


Thanks! Been reading that very thread and several others all evening! You summarized the takeaways pretty well I think. Sounds like sapphire should handle brief heat. I should avoid a sudden thermal shock with a quench, protect the stones with flux. I’ll try an easy solder and see how it goes.

I like the idea of asking Rio about the firescoff-might shoot them a note. Worth the cost for something that protects the sapphires without the risk of etching their surface. They’re listed as “heated” by the supplier so hard to say if they’ve been filled or treated beyond that, but I have extras if need be.

I’ll share updates when I give this a shot. Really appreciating the comments and suggestions on this thread!

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