NOT ALL SODA BOTTLES ARE CREATED EQUAL AND A SAFE PRESSURE FOR ONE BOTTLE MAY BE THE RUPTURING PRESSURE FOR ANOTHER. EXERCISE CAUTION AND WEAR EYE PROTECTION WHILE FILLING THE BOTTLES. DO YOUR OWN RESEARCH FOR SAFE BOTTLE PRESSURES.
You will need a soda bottle, a bike pump, the stem from a bike inner tube, scissors, drill bits, a drill, and blue RTV silicone.
Step 1: Cut the Stem.
Step 2: Drill the Stem Hole
Step 3: Roughing It Up.
Step 4: Make the Fit
Leaving a little space at the base of the stem for silicone application.
Step 5: Seal It Up
Once applied pull the stem and twist it to evenly distribute the silicone and make it snug.
Now apply a liberal amount of silicone to the top of the cap and work it into the hole with your finger while simultaneously smoothing its surface.
Step 6: Let It Cure
Step 7: Finshed
Once again there is a certain level of danger in this project. Especially to the eyes. Please wear eye protection at all times and most of the danger is gone.
Some of my favorite activities for this pressure chamber are releasing the pressure all at once by unscrewing the cap. The confined air rushes out and produces a chilling effect to the hand.
If you place marshmallows inside and bring the pressure up the will shrink slightly. If you allow the marshmallows to return to their normal form and then release all the pressure at once they will expand greatly and have a fluffier texture compared to the normal marshmallows.