Thanks so much for your interest in scratch building a Compressed Air Rocket launcher. We’ve put a lot of research and development into the CAR v2.0, v2.1 and new v2.2 kits as we’ve found the right parts in the right combinations to get the best performance. Because of this, we really recommend going with the kit which in the long run is much cheaper than sourcing the individual parts, as we are working directly with a volume manufacturer. However, we know makers are going to make, and experiment, which we want to encourage, so here are some suggestions for parts. The performance of the parts below has not been verified.
But in the spirit of DIY here goes…
Bill of Materials
(1) McMaster 6646K250 $30.26 Quick-Exhaust Air Valve without Flow Control Right Angle, 1/2 NPT Female x 1/2 NPT Female
(1) McMaster 44605K134 $3.31 Low-Pressure Black Malleable Iron Threaded Fitting 1/2 Pipe, 90 Degree Elbow, Female x Male
(1) McMaster 44615K544 $4.27 Standard-Wall Black Steel Threaded Pipe Nipple 1/2 Pipe Size x 12″ Length
(1) McMaster 4513K830 $2.05 High-Pressure Forged Black Steel Thread Pipe Fitting 1/2 Pipe Size, Cap
(2) McMaster 7753K164 $7.91 Standard-Wall Steel Thread-on-One-End Pipe Nipple 1/2 Pipe Size x 12″ Length
(1) McMaster 7753K163 $9.30 Standard-Wall Steel Thread-on-One-End Pipe Nipple 3/8 Pipe Size x 12″ Length
(1) McMaster 4513K347 $1.62 High-Pressure Forged Black Steel Thread Pipe Fitting 3/4 x 1/2 Pipe Size, Hex Bushing
(1) McMaster 44605K345 $2.88 Low-Pressure Black Malleable Iron Threaded Fitting 3/4 Male x 3/8 Female, Hex Reducing Bushing
(1) McMaster 44605K245 $1.14 Steel Hex Bushing, 1/2 Male x 1/4 Female
(2) McMaster 5111K820 $2.24 Push-to-Connect Tube Fitting for Air & Water Straight Adapter for 1/4″ Tube OD X 1/4 NPT Male
(1) McMaster 68095K226 $16.88 Low-Pressure Forged Steel Flange Threaded, 1/2 Pipe Size x 3-1/2″ OD
(25′) McMaster 5108K43 $15.00 Abrasion-Resistant Clear Polyurethane Tubing 1/8″ ID, 1/4″ OD, 1/16″ Wall Thickness – Use a 10′ length of this tube.
(1 pack of 10) McMaster 3006T78 $4.38 Bottom-Load Clamping Hanger Zinc-Plated, with Bolt & Nut, for 11/16″-13/16″ OD, 50 lb Work Load Limit – 4 required for the build, steal screws and nuts from 2 more.
(1) McMaster 8063K37 $3.94 Brass Air Fill Valve Straight, 1/4 NPT, 1-5/16″ Overall Length
(1) McMaster 4622K33 $24.32 Sliding-Sleeve Brass Air Valve 1/4 NPT Female x Female Connection – replaces previous E-Stop button valve
McMaster Total $139.65
(1) 18″ x 18″ piece of plywood for a base
(4) screws or bolts to mount flange to base
(as required) Teflon Tape
The DIY build is essentially the same as the kit instructions with the exception of the stand. The parts laid out look something like this (note the red mushroom valve has been replaced by a slide valve – better durability, better performance & easier plumbing):
The special stand for the DIY build looks like this:
The launch tube is clamped to a 6″ piece of pipe which is then clamped (with 1/2″ conduit hangers) to the 1/2″ floor flange. The floor flange is then screwed down with wood screws to a piece of wood of your choice. The smaller diameter launch tube is used for launching the ARG kit, or smaller diameter paper & tape rockets.
PDF drawing with Bill of Material: BYOCARv2.0