Making a Custom Platinum Diamond Engagement Ring




So, I am a professional jeweller.

I also sell some items on

If you are realy bored, you can visit my flickr page

A client wanted a traditional design for his engagement ring.

This instructable shows you how his ring was created using the lost wax casting system.

To begin with I cut a section of jewellers wax, ( a special wax that has great properties for cutting, sawing and carving) into the basic ring shape. I created a hole the same size required for the finished ring.

Step 1: Seating the Diamond.

The 5mm princess cut diamond is set into its postition in the ring.

I decided how high the diamond was to sit, then using small engraving tools, I cut a square hole for the diamond to sit in.

You can also make out lots of faint white lines on the wax ring blank. These will determine which partsof the wax are to be cut away to form the shape of the ring.

Step 2: The Basic Shaping.

I have now cut away the major excess parts of the wax, and the ring begins to take shape.

Step 3: The Setting Is Begun

I have now carved out the setting for the diamond.

Once this was complete, I scribed the central part of the ring shank, so that I could determine how wide the ring was to be.

Step 4: The Ring Shank Is Cut Back.

I have now used the scribed lines to cut the ring shank back to the required thickness.

The wax is now beginning to look more like an engagement ring.

Step 5: The Prongs Revealed.

The client wanted a four claw prong setting for the diamond.

Here you can see that I have cut back the wax in the mid section of the setting to reveal the four corner prongs.

Step 6: Making It Visually Lighter.

The ring shank and setting were too "heavy" VISUALLY. So I created some airholes, to make the ring more delicate.

Step 7: Making a Mould

I could have taken this ring directly into the "lost wax casting " process, but I decided to make a mould first.

Sometimes in the casting process, their may be a casting failure, where the item doesn't cast perfectly. By making a mould, I can create duplicates of this ring.

If the first wax produced, fails to make a good platinum cast, I can simply go to this stage and create another wax model using the mould.

During the "lost wax casting " process, the wax is lost in the process when it melts in the kiln. By making a mould I wouldn't have to re-carve the model should a failure occur.

Step 8: Pouring the Mould.

I use a simple two part RVT silicone moulding compound when I create my moulds.

You can see that I have half poured the liquid rubber into the mould box. I stopped to take the picture, and the mould box was filled to completely cover the ring model.

Step 9: The Finished Mould

Here is the finihsed mould 24 hours later.

Encased inside is the wax model.

I use a sharp blade to cut the mould open, to remove the wax model.

The cavity left in the mould is a perfect copy of the master wax model.

To produce more wax models, liquid wax is injected into this mould. Within 30 seconds, it cools and the mould is opened to reveal a wax duplicate.

If I wanted to produce hundreds of this design, I would simply use this mould again and again. tat however is for the "high street". I make unique items for each client, so I won't re-use this mould again.

Step 10: A Ring Is Finished.

The wax model is then sent off to the platinum caster.

Whilst I cast my own gold and silver items, platinum casting requires some very specialist equipment. So the wax is used in the "lost wax casting process" and the platinum ring is returned.

I then clean up the cast piece, I file, sand and polish it and set the diamond.

Here is the finished item.

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    177 Discussions


    2 years ago

    Amazing, Thank you!


    6 years ago on Step 7

    Thank you so much for posting this - I made my first very detailed wax ring and couldnt imagine all that work being burned away. I searched all over the internet and could not find anything about anyone saving their wax model . . .only how to make copies of a master - until now : )
    I dont understand why everyone doesnt do that - what if the casting doesnt work?
    Very nice job!


    11 years ago on Step 7

    This may seem like an obvious dumb question, but it is before you pour the mold, that you remove the diamond correct? I don't see that in the instructions and this seems to be the most logical place for that to occur.

    2 replies

    Reply 11 years ago on Introduction

    You are right. If the diamond were to be left in place, then the mould would capture this cavity, which means any waxes produced from the mould would then replicate the diamond in place. So the diamond has to be removed when the mould is made.


    Reply 7 years ago on Step 7

    Hey Chris, My question is, if you have the prongs built over the diamond as pictured, how do you remove it? Do you cut it free and leave "V" tabs extending up to later be folded over the diamond or are you leaving more of a prong that you will cut with a graver prior to setting and folding it over the diamond?

    I'm including some photos with hopes that you might offer me any suggestions on the best way to set a round diamond into this configuration or point me to a resource vaguely like what I'm doing… I know, I'm a newbie… but this is a great learning experience!

    I'm asking because I'm building a similar four prong semi square configuration to hold a round diamond. I have the measurements for the diamond so I'm building it just smaller than the diamond in order that someone (not me) can cut in the diamond and somehow fold over the prongs that have been cast into the ring. I do not want to use wax wire, I really want to "build" the prongs into the mold


    8 years ago on Introduction

    i have tried some crude lost wax process casting with aluminium alloy.. but this just ROCKS!!! mine doesn't even come half way close to this finish..

    **- HEY!! u didn't give a riser for the cast!! how does it work then? how u avoid blow holes or cast defects????

    1 reply

    Reply 8 years ago on Introduction

    The finish you see in the final image is not what you end up with when you break the ring out of the mold after casting. It is then the jeweller's job to grind and polish the ring to make it look nice. The stone is then set.

    The process for casting precious metals is quite different compared to casting metals like iron, brass and aluminium. For one, you are often working with a much, much larger quantity, requiring risers to be employed.


    8 years ago on Step 10

    The step I would love more info on is carving the hole for the stone. I've tried doing this and found it near impossible to carve a hole just the right size and which held the stone well underneath. Do you melt the wax and press the stone in?


    8 years ago on Step 10

    why do you have to make another wax ring? wouldn't you just give the platnium guy the original? cause then you wouldn't have to make a mold?


    Reply 9 years ago on Introduction

    look up carving wax. the more hard the wax is, the more brittle it will be. for really detailed work, you want the hardest wax.


    9 years ago on Introduction

    thats a great instructable. i used to work in a ring manufacturing plant. i was the "detail department." we made high school, collage championship and some superbowl rings. i was quality control at the end of the line before the wax rings went to tree-up (where they put all the rings on sprues, it looks like a tree and they invest and cast about 20-30 rings at once). sometimes i'd have to add wax to the shanks of the rings and re-carve letters or whatever got messed up. really cool job, as i love to work with the tiniest (sp?) most detailed things. got laid prices today :/


    9 years ago on Step 9

    Wait, I have a question. So, this big block of rubber has your carefully carved piece of wax inside it, and you start slicing it in half with a knife? This sounds scary. Aside from experience and care, is there a technique or something to keep you from scratching or cutting the outside of your piece?

    4 replies

    Reply 9 years ago on Introduction

    I don't know about preserving the original, but considering it is a mold, as long as you cut precisely you could simply re-mold a new one out of wax, this time with the mold already sliced in two for easy access to the ring.


    Reply 9 years ago on Introduction

     there are ways to make to mold with the slice already in it, by pouring half, then pouring the other half..... but in this case, because of the air holes, i dont see how you could cut the mold in half without having to cut the ring in half...... i guess thats why im not a jeweler!


    Reply 9 years ago on Introduction

     see the big block of rubber is a mold, so you don't really need the carved wax. 


    9 years ago on Introduction

    Hi. Really interesting regarding the wax model. 
    My jeweler has made a wax model for the platinum ring that will be made. It is wide, at approx. 14.5mm at the top which tapers gradually to 8mm at the bottom (shank.) The finished ring will weigh approx. 26dwt.
    He rounded the inside edge of the wax.  Will this enable the ring to spin around on my finger compared to if he left the inside edge squared?
    I have other rings with squared (not rounded) inside edges which do not spin on my finger, which is how I like it, and was wondering if a rounded edge would have the opposite effect.
    Thank you for any guidance.