To invent, you need a good imagination and a pile of junk. – Thomas Edison
Things you will need and use
Of course you will need bottles! Carbonated soda bottles are what you will need most. Collect as many as you can because different brands may have slightly different bottles. Some bottle necks may be too small for the launch pipe that must fit inside. 1 liter and 2 liter sizes are most used, but even 3 liter bottles can be flown or cut up for parts. Avoid ones that have dents or creases as they may burst sooner under high pressure but they still might have salvageable parts to cut from them. I have heard that ginger ale and seltzer water are bottled under higher pressure so those bottles may be stronger but I have not tested them. You may also cut sections that won’t need to be pressurized from non-carbonated drink bottles.
The flange around the bottle neck is bigger in diameter on some older bottles that I have saved from many years ago. The bottoms of the old bottles were actually round instead of having 5 bumps like today, perfect for nose cones! The bottle’s bottom was glued inside a plastic cup so it could stand up. If you could pry off the glue without damaging the bottle you had a perfect start for a rocket. I have a dozen of these bottles with the cups still attached. The bottles’ sides have distorted with age so they probably shouldn’t be pressurized but they will be used for some nose cones.
Save a variety of round plastic containers, both cylindrical and tapered. Keep plastic jars, large drink cups from fast food places, food containers for yogurt, cottage cheese, or margarine, and small take-home containers from restaurants. Look for plastic and styrofoam cups that will fit over the types of bottles that you might use. A certain cup may be just the right size to make a fairing, a tapered wind resistant transition piece, between a bottle and a smaller nosecone or other part of your rocket. Heavy plastic lids from the containers may also be cut up to make other parts such as small fins. The cardboard tube containers from “Pringles” snack chips can even be useful if they can be kept dry.
Prescription bottles can be used to make and house small mechanisms when you experiment with deployment gadgets. The straight midsections of plastic jars that match the diameter of your rocket bottles can be made into ring fins.
PVC Pipe and other tubing
PVC pipe is available in many sizes for plumbing. Unfortunately for hobbyists, the size that PVC pipe is labeled is not the actual inside or outside diameter of the pipe! The labeled size is meant for compatibility with older metal plumbing pipe sizes and fittings that existed before PVC was invented. Size charts are available that supposedly give the actual inside / outside diameters of standard PVC but if a dimension is really critical to what you are trying to piece together, it’s best to take a sample piece along to the store to make sure that it will fit.
TIP: There is also some other small diameter plastic plumbing pipe that is labeled ZURN(R) PEX. Size 1/2 inch PEX is 5/8 inch O.D. , rated 160 P.S.I. for cold water and is a tight forced fit inside the 1/2 inch PVC that fits bottle necks. Use it to join or reinforce 1/2 inch PVC where you want to place a smaller O-ring or garden hose washer. Hose washers have a 5/8 inch I.D. so they fit perfectly around the PEX tubing. PEX does not seem to be as rigid as PVC so long pieces are not straight. PEX also carries a warning not to install or store in direct sunlight.
Electrical conduit comes in metal as well as plastic versions. While not rated for pressure, small pieces may be just what you need to mate different size pieces of pressurized pipes together.
Pieces of metal tubing from tent poles and backyard shade canopies may come in sizes in between standard size pipes and could be very helpful. Those odd looking fold-up chairs are made of some kind of tubing. Watch for things like that put out on trash day!
Save the sprayer mechanisms from discarded spray bottles. Clean them first by spraying warm sudsy water through them. You may be able to use the small tubing as you develop more advanced gadgets. You can also salvage small metal springs and o-rings from some of them.
Water Noodles! Floating toys for the swimming pool. These are seasonal items so grab them while you can. They are lightweight hollow tubes made of high density foam in bright colors. They are easily cut to length to make nose cone tips for impact protection. A soda bottle neck can be forced inside the tube and the bottle’s flange will hold it on. Instant “nerf” rocket. Thinner rings can be cut for cushioning between pieces of bottles that are force fit together. A short piece can be glued or double-stick taped to the bottom of small bottles to add a little nose weight for simple rockets. Since they are hollow you can plug the end with a scrap of foam rubber and even add a little more weight inside if necessary.
Thin plastic table cloths come in many bright, easy to see and find colors. They can be found at party supply stores and “dollar” stores. The rectangular style is 108 x 54 inches in size which lets you make eight parachutes of 27 inch diameter for a dollar! This plastic has a cloth like texture and does not seem to have a static cling problem like some trash bags and drop clothes do. It is heavier and has no trouble springing open after being folded. Like any other material, don’t keep your parachutes folded and they will work better and last longer.