Our club is recently reviving lost wax casting. Equipment has been upgraded and beginning classes are underway. I have several questions owing to our recent experience.
1 - A fair number of beginning projects are having issues with filling the cavity completely. The project was a single pre-cast wax ring in a single small casting flask - not multiples on a tree. Basic cylindrical rings casted well. Signet-style rings all had serious issues.
While there were no issues during fabrication using the pre-cast rings (we just added sprues), a key blame is being placed on the wax as being âoldâ.
While the variety of wax material (rings and sprues) are up to 10 - 20 years at most, all are pliable, melt well, and do not crack. (e.g., has not melted or has not crystalized). The fix is proposed as throw out all wax and buy a complete new supply. As the âoldâ wax has not been tested against new wax, Iâm anxious about this as the sole issue.
Can others point to issues with old wax that we should be aware of?
2 - I suspect a key issue is improper or inadequate spruing. (Weâre all beginners.) Can folks suggest an excellent book or two that give practical information on spruing for different scenarios?
Rather than use centrifugal casting, you might look at sand casting. Craig Dablerâs DIY Castings Group fb should get you started. Itâs far less scary and cheaper to do. He has totally changed how sand casting works. Nice not grainy results. You can cast from waxes and many other things. Just a thought.
Judy Hoch
I donât think the wax is the issue. Do you have adequate sprues? Have you made a paste of the investment to paint on and fill more intricate areas before filling the flask? Is the investment the right consistency? Was your silver fluxed and heated to the right temp for the casting process?
Did you properly weigh for the right amount of silver to fill the space? Did you have the right amount of rotations enough centrifugal force?
These questions are important before questioning the wax. And one more reminder, itâs cast, not casted.
I agree with Pbkaren. I think you needed to add sprues to signet rings and make sure you have the proper amount of metal. Also, sprue failure can be an issue. I use âPerfect Purpleâ to attach my wax sprues to both the piece and the main sprue. I tried just melting the sprue wires, but some of them would partially detach during investing and vacuuming. Itâs expensive, but worth it. I use wax that is really old and havenât had problems with it.