Picture of Lost Wax Casting
This is a brief outline of my lost wax casting technique. There are several ways to cast, this is just the way I do it as a one woman show!

You can view a lot of my finished work at

To see more tips, techniques and musings check out my blog -

I use all sorts of random tools for my wax working. Most importantly, my fingers, and a tiny needle in the end of a pencil! I also made a little denatured alcohol lamp out of a baby food jar. The wax I use most of the time is a soft brown wax. Its my favorite.
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Step 1: Wax work 1

Picture of Wax work 1
The beginning of one of my flowers

Step 2: Wax work 2

Picture of Wax work 2
Another flower ring, almost finished

Step 3: Wax work 3

Picture of Wax work 3
This flower is all sprued! Spruing allows the wax to melt out of the mold and for the metal to get to your piece! not having enough sprues or having them in the proper location can cause your piece to not turn out.

Step 4: Weighing them out

Picture of Weighing them out
After all sprues have been attached its now time to weigh them. This if very important and is often forgotten. The weight of the wax is used to determine how much metal you will need for the casting. Because each metal has a unique specific gravity - you will need to know what number to multiply your wax weight by. For sterling, you can do it two ways - you can multiply by 10.4 and then add a half ozt (troy ounce) or you can simply multiply by 15. I usually do both to be on the safe side and figure something in the middle. For very small or very large, using the 10.4 plus half ozt is usually best.

Step 5: Attach to Sprue Base

Picture of Attach to Sprue Base
After the waxes are weighed, its time to attach them to the sprue base or button.
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Sure Hacksalot made it!3 months ago

Thanks for providing this Instructable! It was one of the key
documentations I used for my engagement ring, and I really appreciated
being able to reference this document.


Whats the vacuum machine called by the way?

I've been thinking about doing this for a while now and was hoping to get some gear together.

Great tutorial btw :)

It is actually fairly easy to make your own vacuum chamber and kiln - take a look at the way I did my engagement ring (

rabiddream5 months ago

Out of all the tutorials I have been looking at on the lost wax casting process, yours has been the clearest and most helpful of the process from wax to finish. Thanks much!

E86HotWheels7 months ago

Safety eyewear is important. From the torch pics, it's clear no safety eye wear is being worn. Visorgogs are inexpensive and provide splash and impact protection. They can be found on amazon. Your eyes cannot be replaced. Accidents are called accidents for a reason. If we knew they would happen, then we wouldn't have them.

The tutorial is well done otherwise. Safety is important.

TheStudio72 years ago
Wonderful. I am definitely going to try this. Thank you for sharing.
deth2all2 years ago
I made a lil video of me making a few things , Great instructable by the way, Very detailed .
madmanmoe642 years ago
From what I can tell the investment mould is destroyed each time to get your piece out.
If I wanted to cast multiple copies of an item can I use silicone rubber moulds to cast multiple wax masters?
I've tried pouring carving wax (not decent jewellers wax though) into a mould and it was far too thick.
bcyrjewelry (author)  madmanmoe642 years ago
Hi there! So sorry for just responding - You can definitely make a silicone mold for making multiple wax copies. I prefer to make each wax individually (to make them all slightly unique) so I like the one time use. There are a lot of different mold types/materials. I don't make many so I'm not a great source of information on that topic... Most people use some sort of wax injector for their molds. I have a friend that uses a syringe and pipes it in to the mold that way. There are different types of wax for using in a mold though - with better flow most likely than just a basic carving wax.
Gilligan922 years ago
This is a great guide to lost wax casting and I really enjoyed it. I do have one question though. How do you determine how much metal (in my case white gold) you need by the weight of the wax? What is the equation I need to use? Thank you for the great instructable and your time.
bcyrjewelry (author)  Gilligan922 years ago
Hi there!
Each metal has a conversion factor - the "specific gravity".
I use this chart on the H&S site since there is where I buy my metal.
Standard nickel white gold in 14k is 12.7. Which is different than 18k or palladium white gold.

There is also a phone app I have that does conversions called iMakeJewelry.

Multiplying the wax weight by the specific gravity will give you the metal needed for the piece. Then you need to add extra for a button. My buttons for gold tend to be a lot smaller than sterling - especially with vacuum casting - generally around 4 - 6dwt depending on the size of the piece.

Hope that helps!! Let me know if you have any other questions!
blindpig5 years ago
Have you considered "steam casting" as an inexpensive alternative to vacuum casting? It is a more primitive method but requires less expensive equipment. Might be considered for experimental lost wax casting trials. Would allow trying the process without buying equipment first. Adding equipment later always an option.
If you have a sec - would appreciate any news / tips re process and gathering tools to do steam casting. send to bridlacy at - w my thanks!!
Guess I don't know how to get my info to ya......Any suggestions?
Brian tried to send some stuff to your e-mail address and am getting "non-deliverable" messages, is everything OK?
bcyrjewelry (author)  blindpig2 years ago
hm... I'm not sure if it's the one through my website - I get emails to that address all the time and I guess have no way of knowing if someone get bounced back when others make it through?
Ozzynny3 years ago
Hello and thanks for this share. I haven't had much experience with casting, but am. About to try and cast some rings using the soft brown wax that you love so much :) Before this I had used the hard carvingwax a few times. Can you tell me how thin is too thin? The theme we are working with it to "give volume to a ring" so there has been folding, hammerng and milling. I have a few quite thin areas because i wanted to avoid a50gram ring :)

Thanks for any advice you can offer!
bcyrjewelry (author)  Ozzynny3 years ago
Hi there! I'm so sorry for just seeing this - you've probably cast already?

It really depends on the metal that you're using as well as what areas might be thin, so it is a little hard to just give a simple answer. I personally wouldn't go below 18g (1mm) for sterling, although some areas could be thinner. My rings are usually between 1.5 - 2mm. If there are some thicker areas and some thinner areas, you can make sure to sprue appropriately to make sure the metal casts all the way. so if you have a thicker band and some small thinner details on top, that would cast fine as opposed to a thin band and even thinner details.

One more echo of ‘great instructable’ plus – any forums / equipment sites to find used tools to do lost wax? Any replies appreciated at bridlacy at
bcyrjewelry (author)  brianlacy2 years ago
i don't actually... I'm sorry! Maybe try checking the forums on Someone there may know of used tool forums...
I'm interested in how you vacuum the metal in. Is there a hole in the bottom of you plaster mold and you put that hole over the vacuum peice?
bcyrjewelry (author)  snowluck23453 years ago
Hi there!
No, there is no hole in the mold. Some people use a wax web around the inside of the flask - so when the wax burns out there is a web of holes that allows the vacuum to pull better. i think that may be useful for larger flasks... i use pretty small flasks and the wax webs just weren't worth it for me. The vacuum just creates suction and slight porousness of the investment is enough. I'm always kind of amazed that it works!

If the investment didn't set up properly or there was not enough investment between the negative space of whatever you're casting and the top, the vacuum can pull a chunk off the mold. It is important to leave about 1/8" at the top of the flask, allows for better pull.

hope that helps?
I think it makes sense now. The vacuum pulls the metal into all the pores of the investment, by pulling the air out.
I have not cast anything since grammar school when I made 1 sided lead quarters and passed them to the NUN who was my teacher, (she was highly impressed, cause I recieved neither punishment or wupp'n). I have heard of centrifuge machines , but cacuum?

I are beez confuzzled, you make the mold using wax positive and some kind of plaster (investment?). I understand you suck the air out of the plaster while it is wet, then bake out the "wax" , but how does one get a vacuum to stay that way when you pour in molten silver? or does one do it real fast and then bell jar it and suck air? The mold being so hot the metal does not solidify while you pour, ALLOWING the bell jar to be used with vacuum, after the monolithis pour, (no dribs and drabs)?

sorry if I am too dense for this. I want to cast a few simple shapes out of silver soon and this looks cool. May I also ask does "investment" material have less of a "shrinkage", Or none perhaps when compared to plaster of paris?

I think I need a primer on this !
bcyrjewelry (author)  spark master3 years ago
hey there!
The vacuum for the casting part does not actually use the bell jar. The vacuum has a toggle switch that changes where the vacuum pump pulls from - for investing it is through the bell jar and for casting it is through the table. If you look at the image #15 - right above my hand you can see the hole in the rubber mat and table. The vacuum creates suction through the investment and pulls the metal in to the fine details once the pump is turned on (it is actually turned in before the metal is poured b/c yes, the metal cools extremely quickly)

There is a tiny bit of shrinkage, though not very much.
I will definitely recheck it all out, since I would think th evacuum would suck liquid metal into the vacuum bore and chamber below (the pump). no?

Is the vacuum system good for casting liquid resin and epoxy goops as well? I know all the non understanding on my part is due to total lack of knowlege.But I would like to make a few item and any info I read first will help in the end.

bcyrjewelry (author)  spark master3 years ago
i totally missed this! I'm not sure about casting other things... I think it would really depend on the mold maybe?
Awesome instructable, but what sort of investment do you use, and if you didn't have a kiln but stuck it in an oven on high, (around 5 hundred or on the self clean thing) for a while would it work to cure the investment, or would it depend on the investment. also could you use paraffin wax
bcyrjewelry (author)  finbar galdeep4 years ago
hey there! I use an investment called 'satin cast' by kerr - it is specifically for jewelry casting and gives amazing detail (down to a finger print!) it also is designed to take the extreme temperatures of the kiln.

I would definitely not use a regular oven for a couple reasons - one is that I usually burn out up to 1300 degrees. For the investment I use, the kiln needs to get much hotter than 500 - sometimes it only goes up to 1150 if I'm casting stones in place.
There might be types of investment that are formulated to cure properly at lower temperatures? I've never looked in to it.

The other thing is that the wax fumes are pretty toxic and I wouldn't want the wax burning out in an oven that was in a house or would be used for food.

You can use any kind of wax and even burn out natural materials and some plastics. (again, that can be pretty toxic too) I have friends who experiment with all kinds of things - some work and some don't.

hope that helps!?
if your using wax not plastics! you can also pre burnout your waxes with steam to remove maybe 95% of the wax! less wax means less toxic fumes.
Chris: Owner Mad Scientist's Laboratories & Cavender & Kin Jewelers

OOps! also if you want to reproduce almost anything plastic in metal IE: tin or plastic soldiers, you can sprue them up and gate them for better flow but you will need a high temp burnout!
Bugsley4 years ago
This is fascinating, excellent Instructale. Lots of great details.
Ichmawida4 years ago
i really want to try this! haha
It seems that those Tables are kinda expensive? Do you really need one like this or can you use an vacuum former used for plastic or a bell jar? also where did you get yours?
thanks :)
mnpazan4 years ago
Very informative! Thanks!

How do you create a seal between the vacuum table/machine and the flask during casting? Looks like maybe a special gasket of some kind, is that right? It looks like there are rings burnt in the surface from previous castings, implying that it might be something that wears out with repeated use and gets replaced. If so, can the gasket be purchased separate from the device?

I have a vacuum setup for resin casting, and it would be super simple to DIY a benchtop unit like that for use with the same pump, if I could figure out or source a seal that could take that kind of heat.
jisaku4 years ago
Is there any way to do this without a kiln?
bcyrjewelry (author)  jisaku4 years ago
i'm not sure about doing lost wax casting w/o a kiln - the investment needs to 'cure' and the wax needs to melt out. there are definitely ways of casting that don't require a kiln. There is cuttlefish casting and sand casting (which i've only done large scale, but i imagine the principle is the same - I have a few friends that do it a lot) With cuttlefish casting, you prepare the cuttlefish and actually pour the metal in to it - it's a one time shot, but no kiln! there may be a tutorial about it on here?
The magazine "Backwoodsman" had an article on cuttle fish bone casting a few years ago. If you google the mag they might have an article index.
ok, thank you
heathbar644 years ago
Very informative. One thing I didn't understand was about the vacuum. I could see when you were vacuuming out the bubbles under the glass dome ok, but how did you use the vacuum during the actual pour of the metal?  Also, what type of material is it that is used for the investment?
yoyology4 years ago
This is making me nostalgic.  I loved casting in my jewelry class at college.  Made a miniature rifle for a friend using brass tubes cast in place in an aluminum stock.  My favorite piece, though, was a sterling ring covered in little mushrooms.  I used a hot iron to melt drops of wax that I dropped into cold water.  The hardened droplets looked like mushroom caps.  Then I rolled tiny stems, attached them to the caps, and "planted" them in a ring form on the mandrel.

We used a vibrating table and centrifugal caster.  I ended up with a few bubbles in between the stems, but they looked like puffballs.  :-)
mlcorson4 years ago
I've only done lost wax a couple of times. In class on a centrifugal machine and once at home with my vacuum. Which one do you think is better? More flexible or more forgiving? I have a dismantled centrifugal machine, but I never liked the idea of spinning molten metal around my workshop.
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