It was about time to give my HotWork cart a real test. I have gathered most of the materials I need to start heating and casting silver and other metals. I need a little practice before I jump right into doing casting so this weekend I set up my propane torch and decided to "condition" my small melting crucible.

Metal cannot be, well lets me say should not be melted in a raw surface crucible. What needs to happen first is that a borax (flux) surface be formed by high temperature heating of borax and boric acid in the crucible. It forms a type of glaze on the surface.

I did some experimenting as I have not done this by myself. At first it looked like I was making popcorn as the borax just puffed up and blew out of the crucible from the bast of the torch. I discovered it is better tho heat the crucible first then add the borax and boric acid. I had a fair amount melted in the crucible and moved the molten puddle around to cover the sides. The excess I pored out onto the old aluminum ashtray. (I made the ashtray in Jr. High School metal shop, 55 years ago.)

Note the pretty blue button. This was after I melted the silver for the first time so I don't know what caused the color. I am thinking I overheated the silver and may have put some of the copper into solution. Now is the time to experiment to see what happens, not when casting a one time part.

I needed to see how effective the propane/air torch would be at melting silver. Like I said, it is better to find out now than in the middle of a real casting project. I had some old silver from cut off sprues from previous castings. I placed them in the crucible cup and fired up the Turbo Torch. The sliver melted very quickly, in fact faster than I was used to using the natural gas/oxygen torch I used in my lessons.

The turbo torch appears to be entirely satisfactory in melting silver. I will be testing with brass and bronze but how quickly it does the job with silver, I anticipate no problems except overheating. Now I know to watch for that.

The other picture is the button of silver I made in this experiment. Again I am sure I overheated the silver and probably lost some copper from the sterling. It is recommended to use not more that 50% old metal in a new casting melt due to the loss of copper. I be watching my heat a lot closer.

I had too many hands full to take pictures during the testing as it is very hot and and hazardous work playing with liquid silver.

You can see the silver after pickling (I'll explain that later sometime) and surface cleaning weights in at 29.4 grams. Pure silver is $21.12 per Troy ounce (31.1033 grams) as I write this and I can buy 5 oz. of Sterling .925 casting grain at $23.48 per oz. ($117.40). There are some shipping costs to add on too.

That little puddle of silver is worth about $22.00 and it was only used to make the sprues and "button" where the silver was poured into the mold. It will be reused but there is always some loss.