I have a friend I have known for fourty years and who has done me a number of favors in the past. He has approached me about possibly casting him a “simple” ball-like cane handle perhaps 2 to 3 inches in diameter and probably including some sort of short stem. He has a number of silver bars he’d like to use as feedstock. I have no knowledge of silver casting though I did a brief review and it appears that I could melt the metal in my electric kiln or in my fuel-fired furnace that I use for iron. I think borax is used as a covering flux during the melt. And it looks like petrobond could be used as well as sodium silicate-bound sand or green sand. He has been warned that sand casting will not produce the surface finish or detail expected in lost wax casting. At this stage I am just kicking the idea around. I imagine some of you have some experience with sand casting silver. I’d appreciate your thoughts on the pitfalls to be avoided, results expected, or any other cautions, suggestions, etc that you might have. Denis
I don't see why it can't be done, you going to cast it hollow to reduce weight?. It's be nice to alloy it with copper and some germanium to make a tarnish/firescale resistant sterling silver (Argentium) and increase the hardness over pure silver. Some really fine sand would help with surface finish and maybe some graphite brushed on the sand. I've done a basic silver jewellery course and the excellent thermal conductivity made silver soldering a pain as you needed to use different melting point solders as the work progressed to avoid detaching earlier soldered parts. Edit: You could use copper as a test metal to prove the process as it melts at a similar temp 1084 deg C vs 961 for pure silver and has similar conductivity, you'd just need some phosphorous copper shot to deoxidize just before pouring.
I did cast the cane handle with pretty good results. Plaster of Paris made a mold that looked great but performed poorly. Despite cooking it at 350 for a few hours to drive off free water, it still seemed to do a lot of bubbling and reproduced detail quite roughly. I next used 120 mesh sand bound with 5% sodium silicate. I also baked it at 350 for 3 hours. Detail replication was good and there was no off-gassing. Lost wax would surely have produced better detail resolution and a smoother finish. But, I simply don’t have time to acquire the needed materials, burnout furnace, etc and then go through the learning process. My friend is happy with the result. I melted the “ leftovers” into a 9.7 standard ounce ingot. His nick-name is “Cactus.” Denis
I will add that I turned, milled, drilled, and tapped the head and ferrule. I used very very (razor) sharp turning and milling cutters and found the silver relatively easy to machine. I did find the metal's softness meant that jawed-chucks tended to lose their grip. So, I only used the 3-jaw to establish a round shoulder on the ferrule that would fit a collet. From then on I used collets as chuck jaws tended to loosen---watch for grabs. Collets held securely without damaging cut surfaces. To mill and bore the head, I padded the vice jaws with soft wood. That prevented damage and allowed good clamping pressure for secure work holding. Common relatively fine files worked well and did not tend to "pin." I expected pinning, but nope. Of course, it sands and polishes wonderfully. Denis
I finally have some pictures. The fellow I cast this for had me and my wife over and he and his wife treated us to Beef Wellington with all the fixin's as a thank you. Whoa, so good. He sent me a few pics this morning. He did the finish work and decided this was the degree of polishing that he liked. It is on an ebony stick. I do not have photos ot the machining of the ferrule and the boring, drilling and 8mm tapping of the head. Most important to me is that he is happy. Kinda makes me want to learn lost wax though... Denis
