Remove the thread of a PET bottle neck with a fine.
Allow a certain roughness (stop filing as soon as the threaded tap connector can just be engaged (screwed) on the bottle neck.
Etape 2Roll about 50 cm of teflon thread seal tape around the bottle neck.
Screw tightly the threaded tap connector on the bottle neck.
It should hold very well (not turn freely).
Cut out 3 cylinders from the central parts of the 3 remaining 1.5 litre PET bottles.
Flatten two of the cylinders with a board.
Cut off the neck of the top part of one of the cut bottles.
Form the "top" of the rocket by placing the "neckless" part on top of the rocket bottle bottom and placing in between the two parts a foam ball.
Fix the 2 parts together with insulating tape.
Cut the flattened cylinders according to the drawing to form 4 stabilizing fins.
Paste double-sided adhesive tape (carpet type) on the upper surface of each fin leaving a free strip of 1.5 cm at the bottom.
Bring the lower part of each fin on the top and press to paste the two sides together.
Cut the fins to their final size as indicated and staple the edges according to the drawing.
Cut the rear corner of the fins and fold both sides to form two 1.5 cm wide flaps.
Cut the remainging cylinder to form a 10 cm high cylinder.
Fix the fins around the cylinder with double-sided adhesive.
Clip the fins with a stapler as shown.
||It is very important that the fins are evenly placed around the cylinder.
Slide the cylinder with the fins on the lower part of the rocket.
With insulating tape, fix the cylinder and cover the staples.
Push the valve gently through the "female" Gardena connector using a long bolt and a hammer.
Push the the valve util its thread comes out the other side (but not completely!).
You can use the cap of the Gardena connector as a support when you hammer.
"Screw" the tap gasket around the valveth.
Screw the extension tube on the valve using pliers to tighten it well against the tap gasket.
Drill a 2.5 cm diameter hole with a metal hole saw at about 4 cm from the upper edge of the larger wood board.
Drill holes as indicated on the drawing with an M4 bit and attach (with bolts and nuts) the metal bars and the small piece of wood to the hinge.
Pass "through the hole in the wood board the "female" Gardena connector and screw its cap on the other side.
Tighten a plastic cable tie around it.
Etape 12Drill the wood slat using an M4 bit as indicated.
Pass the end of the cable tie through the hole "B" of the wood slat and tighten the other side using an electric connector.
Pass through the hole "A" an eye screw and screw it no the board. Leave enough free space to allow the wood slat to move up and down.
Attach a thin rope to the hole "C".