To begin, in a mixing cup, combine oxalic acid and sodium bicarbonate, maintaining a weight ratio of one to two. If the acid-based powder mix becomes crystalline, grind it into a fine powder using a mortar and pestle. To fill the capsules using a semi-automatic capsule filling machine, place the cap sheet on a clean, dry surface.
Align the encapsulation sheet over the cap sheet. Separate the capsule tops and bottoms unless using pre-separated capsules. Pour the capsule tops into the encapsulation sheet and shake the sheet gently in a circular motion to fill the holes with the tops.
Collect the leftover capsule tops in a clean cup. Detach the encapsulation sheet from the completely filled cap sheet and keep the cap sheet aside. Identify and flip the capsule tops that are upside down.
Next, place the body or bottom sheet on a clean, dry, flat surface. Fix the encapsulation sheet to the bottom sheet and secure the alignment with the black pegs. Pour the cap bottoms onto the encapsulation sheet and shake as described previously to fill all the holes.
Then pour off the excess capsule bottoms from the sheet. Remove the encapsulation sheet from the filled bottom sheet. Flip any capsule bottoms found upside down.
Now, disperse the acid base powder mixture onto the filled bottom sheet. Using a plastic spreader, fill the capsule bottoms with the powder. After positioning the filled cap sheet on a flat surface, mount the middle sheet on its top.
Invert the cap sheet affixed to the middle sheet on the filled bottom sheet, ensuring a proper mutual alignment. Press gently, but equally on all sides of the cap sheet to join and fit the tops and bottoms of the capsules. Then remove the cap sheet and the middle sheet from the bottom sheet, leaving the capsule tops and bottoms joined.
Check each capsule to ensure its top and bottom are fitted tightly. If not, manually press and tighten the top and bottom together. Finally, transfer the filled capsules to an airtight sealable container.
