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Making the engagement ring


As long as I was making Shirin a fairytale storybook, I thought it made sense to make the ring as well. For those that are interested, below are the major steps I took to go

From raw material

to a finished, hand made diamond ring

Starting with a hunk of platinum, a diamond and a setting, you can actually create a professional grade ring in 1-2 days. You should note that, for the machining technique I used, access to professional equipment and a professional consultant was critical. If I didn’t have that access I would have used the lost wax casting technique instead.


Designing the ring

The question that all men ask is, “how do I get her a ring that she will love?” It’s a tricky one because, for some of us, the element of surprise is important. How do you surprise someone with a ring that you also know that she will love? My solution was to have a distant friend of hers send out a Survey Monkey survey asking for help on a new online jewelry business she was starting. Of course, the survey only went to Shirin ;) 


This gave us the stone cut, the band style, etc. that we needed. So off to the design races! Or so I thought… it turns out that I missed one fundamental question. I’ll tell you more about that later.

Mining the diamond

You might be surprised at how difficult it is to mine your own diamond, in part because many of the best places to mine diamonds are in war zones. In the end, the Kimberly region of Australia offered the best day rates on the necessary heavy equipment. In a bit under 2 weeks I was able extract ~1,500 tons of raw material, which was enough to produce 2-3 high quality diamonds for me to choose from. Just kidding. I bought a polished diamond from

Method of building

Given the simplicity of the ring style that she wanted, I chose to machine the ring via traditional metal working tools versus using the lost wax casting technique that is used by all the retailers. In theory, machining will result in a stronger ring with less wear and tear over time. In practice I really have no idea if this will actually have an impact. I suppose I could have evaluated a bunch of rings made 60 years ago but…

Making the ring

Step 1 - Create a metal strip with the desired length

I started with a hunk of platinum and extruded it through a hand-cranked extruder. The extruder has several sizes and I simply cascaded down in sizes until I reached the desired diameter. It took 10-15 passes to get it to the right diameter

From this:

To this:

Then anneal it:

After any step that reshapes the metal, it's important to anneal it.  With platinum it’s important to anneal it on something clean so that it doesn’t pick up other metals during the annealing process.


Once the metal is the desired diameter, I cut it to size:

It should end up as a cylinder with flat ends because, at the next step, it is going to be bent around into an oval and you want the two ends to meet up as cleanly as possible.


Step 2 - Bend it into an oval shape

The next machine is a glorified pseudo male/female type machine. On the one side is effectively a hollow half cylinder (the female). On the other side is a full cylinder (the male).

By manually pressing the two together, the full cylinder will sit inside of the hollow half cylinder and anything in between will be bent to make the shape. I put the platinum bar between the two and cranked it. That rounded out a small portion of the platinum rod. After repeating this process 7-10 times, I was able to create an oval shape out of the platinum with the bar ends nearly touching each other:

Step 3 - braze the oval together

The next step was to braze the oval together to form, for the first time, a solid ring.  Make sure the oxy-acetylene torch is ready to go, place the solder over the gap, and get fired up. Unlike traditional soldering techniques e.g. circuit boards, you need to heat up the platinum material first until glowing red. Only then due you place the heat on the solder, which liquefies and flows into the platinum, creating a solid joint:

Step 4 - Create a circle from an oval

This stage is the first time that you get to see a true circular ring.  First step is to hammer in down on a mandrel until you have a pretty good circle. Flip the ring every few hits so that it isn’t wider on one end versus the other. After that, I used this machine here, which can either stretch or compact a ring, to make sure the ring was circular and was the right size 

The cavities are all different sizes and, after finding the appropriate cavity size that fit the ring as it was, I used the manual press to compact the ring until it got too small for that cavity. I then moved it to the next cavity. After each press, I flipped the ring so that it would stay symmetrical. It took 5-10 presses to get the size I wanted (ring size of ~4 1/2)


Step 5 – Sanding

Throughout the process, there’s an awful lot of sanding. The first time that I did any significant sanding was after creating the circle. There was some sanding of the sides and the interior (using something like a fixed dremel).

It was useful to get the basic sanding completed before adding the setting because I could get more aggressive without worrying about hitting the setting.


Step 6 - Cut and prepare for the setting:

Shirin’s ring size, I thought, was around a 5 so you might be surprised that I created a 4 ½ size ring in the previous section. The reason is that the next step was to cut an opening in the ring to place the setting. This expands the size of the ring by, roughly, the width of the setting at the base. You’ll see that I made two cuts, perpendicular with each other and at a 45 degree angle to the side of the ring:

Step 6 - Insert the setting

The setting, which I bought pre-made, had to be popped in to the ring securely. It’s a pretty important step to get right so Adam did this. For background, even though we’re going to braze the setting with solder, it’s useful to have tension on the setting. So we made sure the opening that I cut out was just a bit smaller than the base of the setting, plied the two sides apart and inserted the setting.

Here's the setting that I purchased:

And here it is after being popped into the ring:

Step 7 – braze the setting to the ring

From there, it was time to braze the setting. This requires an oxy-acetylene torch that gets up to temperatures above 3000 degrees. It’s hot! And bright. Like, wearing sunglasses indoor bright.  It is critical to get this stage right because this is the weakest part of the ring. The process is straightforward, if a little nerve wracking:


Heat the platinum until glowing red:

Then hit the braze with the torch, without knocking it off and certainly without heating it up so much that the platinum melts at all.   All in all, it’s 20-40 seconds of heating followed by ~2 seconds of brazing. If you leave it on too long, it’s quite easy to ruin the piece. 


Step 8 - Sand and polish

After the setting was complete, I moved to the f finish work. Basically, sanding the inside and outside of the ring. For some of it, I was able to take advantage of a dremel type rotary tool:

And some of it required manual work e.g. a fine tip sanding pencil for the edges where the solder went.  And then there was some standard sandpaper. I ended up going down to ~1500 grit

Step 9 - Setting the diamond

Setting diamonds is actually a sub specialty, kind of like how you have primary care physicians and specialists.  Given how much a diamond costs and how long it needs to stay put, it’s pretty important that it stays in for the next 50 years.  So Adam directed me to a setter in downtown San Francisco who was nice enough to let me take some photos while we was setting the diamond:

The oops

Remember earlier on when I was so proudt about the Survey Monkey survey giving me all the info I needed to make Shirin a ring that she would love? Well, it turns out that I missed one pretty vital question: does Shirin even want a diamond ring? Her strong preference was for a sapphire. And while she was nervous about expressing her opinion after I put in this effort to make her the ring, I’m very happy that she did.


We ended up returning the diamond and we are buying her and replacing it with a sapphire ring.  We’re going to repurpose the engagement ring into the wedding band.

Step 10 - Propose

Here is the finished ring:


If you are here already, you probably know how I proposed but, if not, I custom built her a fairy tale storybook and hid the ring at the end of it

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