Metal granules are very common decorative elements in designing jewelry. You can solder them on any kind of metal jewelry like this piece of mine or fuse them on vitreous enamel. Granulation is an ancient technique that fuses granules on a metal base. On the flat jewelry designs, they will give a bit of dimension too. When you are heating a small piece of non-ferrous metal, it will melt and granulated to a sphere. I have this video that I show how I am making granules and ball up the end of silver wires.
You can use your metal scrap for making granules, but it would not probably give you granules with the same size if it is important for you. Unless of course you can make granules in various sizes and then sort them using screens of different sizes. The second method to get the equal size granules is to cut a wire in equal pieces and then make granules from those parts. You can simply mark the size you want using a ruler and a permanent marker. Also, you can make a coil around a mandrel or a pen and cut the jump rings. Those jump rings will have equal sizes.
2. Choose a block
I have used few different blocks to make granules (and I should continue testing!) and charcoal block works very well. Also making granules inside a crucible is a good idea to facilitate collecting them. But you cannot make several granules simultaneously in a crucible, because they might join together after melting and make larger balls!
To make spherical granules, you can make some holes on charcoal block and use them to melt the metal. However, to have granules with a flat side, use flat surface of block. You can use these flat sides to solder the granules later.
3. Heating the wires and making the granules
It might be a good idea to heat the block a little using your torch (it will reduce movement of metal pieces a little and I did not do that in the video!), then, aim the flame directly at the metal and it will get granulated very fast. After cooling down, pickle and clean them. I used sterling silver to make granules and they turn black after heating and require cleaning.
Balling up the end of wires
I usually ball up tip of wires to make earrings post. To ball up the end of wire, first flux the wire. I have used boric acid and borax and I think boric acid is a better flux for this option and it makes better sphere and also balls are not turning black. They are turning brown! Look at the picture below.
The ones at the right side are fluxed using boric acid and the ones at left side are fluxed using borax. I have cleaned both after balling up. After fluxing, hold the wire in direct flame to form the ball