I was contacted by a guy who is reproducing a bronze aged artifact called the sun chariot.
The bronze age people believed the sun was pulled across the sky by a horse and chariot.
He has asked me to produce the bronze horse part from his wax sculpture and he intends to do the rest (chariot, wheels disc etc). I thought I would share the process in pictures in the hope that the process will be useful to others and of course for advice form others who have experience of lost wax. I am almost on the sprueing so would be keen to hear how others would tackle this.
Here is the horse put together after receiving the parts. The legs were off for easier packing
I scribed circles in the body that will reproduce the location of bronze rods used by the bronze aged caster to support the central core. I couldnt use this approach myself with the ceramic shell method Iam using as the preheating of the mould would probably melt the rods. I think the ancient peoply would have poured into cold clay moulds so no problem here
This is the detail on the head that has to be reproduced. The grooves are very fine, less than 0.5mm in most places.
I had to attach the bottom of the legs so it was important that the hooves where fairly square to line up with the axle that the horse will stand on.
The horse ready for mould making just the pegs to add to the feet that will attach it to the axle.
Decided to do two moulds, front and back. I did this so that I could have good access to the inside of the body so I could control the thickness of the wax better and thicken up bits afterwords thatI know will not allow the wax to settle on such as the pointed bits of the mould between the legs. I didnt take shots of every step but here are a few of the construction of the front mould. I decided to do it in 3 parts, on for each side and one between the legs
The silicone rubber took the detail very well.
Here are some pics of the rear mould stages done in the same way.
I am concerned about the ceramic shell being tough enough to hold the fine detail without breaking or eroding away either during the pre heat or during the pour. So I cast some waxes of the side of the head to test with different consistencies and applications to see which shell will be the most resilient. I am using molochite 200, molochite 16-30 and molochite 15-80
and primecote binder
Here is a quick cast of the horse just to see if the two halves would fit together and the finished moulds.
Things I have to consider now
Do the bronze casting in two halves and weld together.
Put in a solid core and join the waxes together and bronze cast as one. piece. Preferable but I might not be able to fit it in my small kiln.
Sprueing, whats the best way?
More pics to follow.