This instructable shows you how to make what I call the XRV (explosive release valve), which can be attached to a bicycle pump. This in turn allows you to turn an ordinary blowgun or pea-shooter into something a bit more serious.
The video does a lot of explaining, but for more detail including how it works, see the next steps.
Step 1: Materials and Tools
1. Flexible bike pump hose - comes with most bicycle pumps)
2. Brass or aluminium tubing (about 1-2mm) - available from hobby stores
3. O-Rings (tiny) - available from hardware stores
4. Small spring - also from hardware stores
5. Tiny screw that fits into the end of the 1-2mm tubing
6. Tiny nut or washer that fits onto the brass tubing (see video)
1. Hand drill & very small drill bit
2. Fine file
4. Precision screwdriver
5. Pliers or multi-grips (pictured)
6. Hand clamp
Step 2: The valve housing
Step 3: The valve shaft
Step 4: Valve air flow
With a tiny drill bit, carefully drill two or three small holes into the shaft.
File any rough edges smooth so the tube glides through the housing without sticking at all.