Just a note, unlike in the video, after the bronze is poured and cooled the de-shelling process should be done with a proper respirator and filter, otherwise one can become afflicted with a longterm lung ailment known as silicosis.
What a complex and lengthy process. You have to respect the skill required to master such a difficult art form. There are so many ways this can go wrong, and bronze is also an expensive raw material to work with. It must require significant investment to learn this trade
I have a centrifuge but I don"t know how to adjust the weights and do not know how many times to turn the centrifuge. does anyone have knowledge about this that they will share?
The main wax used is called microcrystalline wax, a byproduct of the petroleum industry. There are many kinds of this wax on the market. An old standard is called Victory Brown, but it has become a bit too soft to use on its own, so many artists and foundries add other waxes to it, 50/50, such as McCaughlin AB55.
The slurry for ceramic shell casting is called colloidal silica, which is a complex mixture, the exact recipes for which are generally held by the various companies making it.
This method is the way I have to go with pouring metal. Sand casting needs too much work. Plus this can be automated far more easily. I was looking into doing it with pur foam but that matter doesn't work the way as lost foam does. However, I keep thinking about how could I cast metal more easily. The way it should work: Have a plaster of paris mould, fill it with lost foam like matter in liquid form, wait for it to solidify, dig it into sand, and pour metal onto it. This would be heaven!!
@iToasterman Reasons for heating the resulting shell: 1) to eliminate the wax 2) to "fire" the shell & harden it into a ceramic like material, hence the name "ceramic shell." Shells are usually allowed to cool after this firing, then reheated for later pouring. 3) This re-heating is to allow the metal to flow better since the shell dissipates heat rather quickly causing metal to freeze before filling the mold, resulting in big gaps. (an edited version of a response from sculptor Tuck Langland)
If you'd like additional information, you can tour a foundry or explore books on the subject, such as From Clay to Bronze: A Studio Guide to Figurative Sculpture by Tuck Langland.
@TheMedievalMan and knowing led me to finish a clay sculpture, called a foundry and had my first bronze sculpture made. I was awstruck with the tour of the foundry in person. WOW I posted a video of the sculpture
thank you for this video 👍. I would like to try making patinas on copper alloys. do you know if we can buy them or if they unfortunately remain secret recipes that the founders will take to their graves 😅?
It's not a secret. Since silicon bronze is 95% copper, pure copper will react pretty much the same way. So, liver of sulfer is the main one, making it dark. Ferric Nitrate will warm up the brown into a more reddish shade. Acryllic paints, thinned way down with water and put on hot, can also be used. More info in the book: Just Sculpt Patinas For Silicon Bronze by Patrick V. Kipper. If in the NYC area, workshop on patina: shop.sculpt.com/240420-patina-hands-on.html
I'm a member on a few foundry sites but none have this type of wax. Can anyone shed light on this type of wax and perhaps a source for it? Also what is the slurry? I use plaster of paris.
plaster of paris is good specially in cased that you can use centrifuge or vacuum casting which means small projects. for bigger projects ceramic shell is better because molten metal can be casted in a red hot mold and it solves the missrun problem. another advantage of ceramic shell is that it is much more porous compared to a solid plaster cylinder. the ceramic slurry is a combination of colloidal silica and zircon powder but if you add some antifoam materials and/or wetting agents the result will be better.
