Corning is the process by which meal powder, or finely divided black powder, is compressed into cakes, crushed, and then screened by particle size into different size categories. This process alters the burn rate of black powder, giving it more flexibility for different applications.
In general corned BP (slightly wetted, pressed with a hydraulic press, let dry, crushed and screened) is nothing faster than hand-granulated or "riced" BP. Some people have shown that the opposite can be true.
However, corning offers some distinct advantages compared to riced gunpowder, the most important of these are:
- Measuring by volume is possible: You can load your devices using special spoons as there is no need to weigh it each time, etc.
- the grains are much more durable and there is less dust
- more weight in a given volume: this is essential e.g. for breaking can shells and riced gunpowder may require boosters to give a hard break
In case you have a hydraulic press, I would go through the trouble. It´s not really that much work and the outcomes are really handy. If you don´t, you can also make good pyro, as corned BP is not essential in most cases.
Take your meal powder and wet the composition with roughly 5 to 10 percent of it's weight with water. Mix thoroughly and place into a die and compress with a hydraulic press until you form a solid cake. The idea is to give the black powder a density of 1.7 g/cc. It can be dried before or after the following step. Next you need to take the cake and break it up in a mortar and pestle or similar. This can be a dangerous operation and should be done in small amounts. You should use a full face shield, hair cover and heavy gloves. You can then screen by particle size into different sized categories for your intended purpose.Note that Black powder can be corned dry. The water does increase burn rate slightly but is not needed to produce hard grains.