I recently found a way of modifying 2 firecracker rockets into a single 2 stage rocket.
The idea worked out very well but as I don’t have a DVR, couldn’t post a video.
Step 1: Parts:
1 large rocket
1 small rocket
A piece of card with width of about 2 – 2.5 inches
PS: Refer to last step if you don’t have rockets of 2 different sizes
Step 2: Prepare the Large Rocket:
Remove the top conical section from the large rocket. There will be a small cylinder under it. This is the part that explodes into flashes once the rocket goes high into the sky. Remove this cylinder as well. Now you should be able to see the gunpowder. (This is your first stage fuel)
Now take the card. Stick it onto the large rocket such that a loop is left to accommodate the balancing stick of the small rocket. This loop should be on the opposite side of balancing stick of the large rocket. Thus the balancing sticks of the rockets should be on opposite sides of the central cylinders. (Refer to pics for clarity)
Step 3: Inserting the Small Rocket:
Insert the stick of the small rocket through the previously made loop on the other rocket. Now the fuse of the small rocket should touch the exposed gunpowder of the large rocket.
Make finer adjustments such as increasing the length of the fuse if needed. Make sure the fuse touches the powder well.
Step 4: Working:
Now you’re ready to launch!
Ignite the large rocket, it will shoot up. Once all the first stage fuel is used up, the second rocket will get ignited (the first will fall down). The second will rise further and then the cracker will explode!!
Step 5: Further Note:
If you don’t find 2 rockets of different sizes:
Take cardboard roll of a larger diameter than that of the rocket you have. Fill it up with gunpowder and attach a fuse and a balancing stick. Use this as the larger rocket and proceed with earlier procedure.
This part being dangerous, keep safety procedures at hand and take care.