LUTHANG is a very simple toy to make. It is basically a plunger operated pneumatic gun constructed by using a small diameter bamboo section about 12-16 inches or so which serves as the luthang barrel or cylinder. The plunger/pusher is just a solid wooden stick or another bamboo with a handle.

The outside diameter of the plunger/pusher stick should be very close in size to the inside diameter of the luthang barrel and should be able to slide freely in and out when inserted. The part of the plunger assembly should have an insertable section that is about half an inch shorter than the total length of the luthang barrel. The unexposed section of the plunger stick is fitted to a handle of any appropriate size you want.

The projectile is just a wetted piece of paper formed into a small ball that can be inserted somewhat tightly fitting into the barrel by using the plunger. To prepare the luthang for firing, an initial wetted paper projectile have to be first pushed into the barrel all the way to the end. That’s the reason why the insertable part of the plunger have to be about half an inch shorter because you do not want that “projectile” to be pushed out of the barrel during loading of this initial plug/projectile.

The next step is to insert a second wetted paper projectile into the barrel but only about 2 inches or so from the breech end (the end that will be closest to the shooter). Pointing the barrel at an intended target and giving the plunger a forceful sudden push all the way to the hilt of the handle would create a sudden air pressure rise inside the barrel space trapped by the two inserted wetted paper projectiles.

The resulting high air pressure will make the forward projectile pop out of the barrel at a very high speed just like in an air rifle with a similar sounding loud POP. The previous rear projectile that was inserted by the plunger will now stay at the forward part of the barrel ready to be fired as soon as another wetted paper projectile is insert at the breech end just like the way you have previously done.
If bamboo is not availble in your area, you can use any small size PVC pipe or whatever that is available to serve as a barrel. Even an aluminum tube with a smooth bore will work fine. Just use your imagination with whatever material is available to serve as alternative construction materials for the barrel and plunger. For an alternative projectile you can also use unripe fruits (like a papaya fruit meat or a chunk of raw potato meat) that can be inserted with a moderately tight air sealing fit inside your chosen barrel.