The cap shells are made using a tool die cap maker out of aluminum can metal. The ignition powder is made from toy cap gun powder cap strips. Use a punch to remove 3 powder dots off the cap strip. Insert the papered dots into a percussion cap shell. The dots can be secured with a tiny bit of straight Duco cement or that cement slightly diluted with acetone - allow to dry. Done. All 24 of the caps created so far had instant ignition. How they will work with igniting black powder in a firearm chamber remains to be observed.
An alternative "wet" method is to cut 9 of the powder dots off a cap strip and soak in tepid tap water for about 15 to 30 seconds, remove the strip and lay down on a flat source, lift and peel off the red top strip in order to reveal the black powder dots, use the tip edge of a knife to scrape off and collect the 9 powder dots, put the accumulated powder into a cap shell, tamp down lightly with the blunt end of a BBQ skewer and allow to dry. Done. I created a dozen of this kind of cap build and every cap went off with big bang and flash, probably near as powerful as a CCI #11 cap.
In both above cap making types, the DIY aluminum can caps had a really good fit on either an Uberti or Pietta 1851 Navy .36 pistol. It should be noted that unlike using commercial percussion cap powder making chemicals, toy gun caps did not cause metal rusting. This is the main reason I avoided going that chemical route.
Wet method test firing ...