I have mounds, tubs, and drawers full of silver scraps in all shapes and forms. Dust, filings, spirals, corners, wire, failed projects..... I want to reuse my scrap and make fresh stock from it.
I just got this nifty graphite ingot mold. Each compartment will hold 5 ounces (or was it 10?) of silver. So after a few trial runs and many more needed, I produced one somewhat useable ingot. I think I need more practice. And oxygen for my torch.
Here's what I learned:
1. Make sure the mold is ripping hot before you pour. As soon as the molten silver hits cold graphite , it shrieks and promptly cools. Ok, it doesn't shriek, but imagine what you would do if you jumped into the north Atlantic Ocean in February. See? Shriek. If not poured into a hot mold, the ingot in question will not be lovely and solid, but a disastrous mess of folds, pits, and air bubbles. I should have known this. I've poured into iron molds many a time and I always, always, always get the mold smoking hot right before I pour (and it is really smoking 'cause the oil on the irons surface begins to burn away.... and the oil is there to keep the molten metal from sticking to the mold).
2. Make darn sure that there are not any foreign objects in your scrap before you melt. When I say foreign, I mostly mean steel or iron. Check out the image above. I circled what appears to be a chain popping out of the surface. I actually saw the chain floating around in the molten silver and honestly tried to fish it out with a pick. I'll have to melt this down and try again.
3. Be set up (that is, have enough scrap on hand) to pour more than once. Nothing gets a mold nice and hot than a fresh pour. Use this to your advantage.
4. Weigh out your metal as to have enough to pour a decent sized ingot. I did not do this. The image above shows a so-so pour. If I had more metal rolling around in the crucible, the ingot would have filled nicely to the sides of the mold.
5. Lastly, make sure that your studio is properly exhausted or get a big fan going and open a window. And be warned, your smoke detector will go off. And warn your family that the detector just may go off. Warn them especially if they are all in bed because it's an ugly scene otherwise.
Happy pouring!