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The Lost Wax Casting Process | Centrifugal Casting

Hello Everybody -- Michelle here... I decided to create this informational page after receiving an order from a very well known Publishing Company for several hundred of one style number they needed for a certain book-release party...

I let them know that since it was such a large order of one item number, it would be about 6 weeks until we'd have them ready for shipment & she (the buyer) asked,
------------ drumroll please ------------
"No Problem, but Don't They Just Have to Dry?"

"Um, No... I Wish It Was That Simple, Though..." - I reply

Nope, the process isn't Very Fast or Glamorous, but Interesting! :)

Please Find Below a Description (with Pictures) of the Lost Wax Casting Process
Before ya ask... No, we don't make EVERYTHING on the site...
But for those Sterling Silver items that are :


All Items begin with a Master that has to be carved, sprued & then cast. Then a Mold is made of the item.

wax working toolsvulcanizer -- used when making molds from a mastersome of our molds
Yep, lots goes on before what I'll be going into below...
I'm not going to go into that here, but rather, I'll start with once the Mold has been made....

1 - Squirting the Waxes
All items are hand-squirted with the help of a wax injection machine, ONE-AT-A-TIME!
Yes, how very fun... and time-consuming....
Different injection pots & wax mixes are used for different items.

squirted wax - part #1738squirting waxes -- wax injection squirted wax
If the wax is not perfect, it is rejected as the finished piece will not be good... That's the rejects in the wax-catch bin.
Next comes...

2 - Mounting

Now that each wax has been squirted, it has to be mounted (again One-At-A-Time) onto a wax base using a hot wax pen.
Different-Sized Bases are used depending on the item.

mounting - ringed music note finished base #2842 - triskellion

In General, About 20 to 50 squirted waxes are mounted to each base... One base is dedicated to each item.
finished base - shooting star finished base - samples
After the mounting is done, each base is then Flasked (covered with a metal flask cover), weighed & taped to proceed to the next step....

3 - Investing
OK, Now Comes a Fun Part... Investing (or 'Making the Muffin Mix').
Investment powder & water are weighed out on scale & then added to a mixer & given a whirr....

investing - part 1 - mixing

After the water & investment has been thoroughly 'mixed', but working very quickly... it then has to be vacuumed to remove air from the mix & distribute the investment tightly around the waxes.
vacuuming the investment vacuuming the flasksinvested flasks
The investment is then poured into the flasked & taped flasks... & Vacuumed again!!!

The 'Muffins' are now done...

They are then scribed with the Silver, Gold or Copper Weights...
And left to dry for a couple of hours...

The flask bases are then removed & the flask covers are then scraped clean....

Then a Bunch of Clean-up Happens...

ELAPSED TIME... SEVERAL DAYS SO FAR... Investing, however, is done in 1 Day.

scribed flasks
Generally 21-flasks or three batches of 7 flasks are done at one Investment time.

4 - De-Waxing and Burn-Out
The evening before a casting day, De-Waxing & Burn-Out Occurs.

OK... This is why this method is called the 'Lost Wax Casting' Process.

After the flasks have dried for a few hours, the flasks are then placed in a De-Waxing Chamber.
The wax is heated up & 'drips' out the bottom of the flask through the channels created by the sprue...
The Wax is 'Lost' -- Get it???!!!



After the flasks come out of the de-waxing chamber, they go into a Kiln.

Overnight, the kiln goes through a heating process/program that raises the internal temperature to over 1300°F -- which burns out / vaporizes any remaing wax left in the flasks.
It then slowly cools & holds at around 900°F.

5 - Casting - Centrifugal Casting Process
Burn, Baby, Burn... Disco Inferno! -- It's a 70's Disco Song... I'm showing my age!
Anyway, here's the 'Intense' Part of the Process.

oxygen & acetylene tanks
To Reach the temperatures needed to melt the metals, an Oxygen & Acetylene torch is used.
Sterling Silver Melting Temperature - 1640°F | Copper Melting Temperature - 1981°F
14k Gold Melting Temperature - 1615°F

casting heating the metal
hot crucible hot flask
As the metals reach melting point in the crucible, the tensioned casting arm is released,
the cradle & arm spins at a high rate
& the metal flows into the crevices created by the sprue via Centrifugal Force.
This is why this casting method is also called 'Centrifugal Casting Process'.
In some circles, this is also called 'Spin Casting'.

The hot flasks are then 'quenched' in water.


6 - Cleaning & Finishing
There are Several Cleaning & Finishing Processes involved...
This part, like the 1st processes are the most labor-intensive & takes a few days.

NOTE: Items don't look lovely until the very end.

#2016 after casting - quenching water-jet cleaned

The 1st finishing process is cutting the Pieces of the Base -- the base is then termed a 'Button'.
cutting items away from the base

After each piece is cut, it then goes a few hours in the 2nd cleaning process to remove the remainder of the Investment material.
1st tumble
cast sterling silver -- still on sprues

Then the sprue is cut off of each piece & is individually sanded.

Then they all go into the tumblers again.

--Many more mechanical and hand-finishing processes happen over a few days.

(Please see How Earrings are Made Section for Some of Our Other Processes).

Items are dried, sorted, and sent out to YOU!!!

If you want to learn more, here's a book recommendation:

jewelry casting book recommendation
Sorry, but please Do Not Contact Us if you are wanting to learn how to cast or are having casting problems... Please see book recommendation (above) if you wish to know more...

Hoping you Find this Page Interesting!!
We'd LOVE to hear from you if you do!

Enjoy Your Visit & BB!
~ Michelle, Dianna and Joseph ~
The Family-Owned & Family-Operated Team of Silver Enchantments LLC.