It depends on the length of your barrel as well. A longer barrel will negate some of the effect of having a small valve size as it gives more time for the pressure to build up behind the object being shot before it leaves the barrel.

I was sitting at home bored and after a quick trip to wal-mart and 12 dollars later I had an interesting new pneumatic cannon. I used 3/4" SCH 40 pipe with a ball valve for the chamber (small I know). I actually found a aluminum sprinkler that was pressure rated that extends out or is removable. Its ...

That sounds like sound advice so I am going to start small and build something more reasonable first and then work on a bigger one next semester, since it will be easier to compute the chamber size and barrel length needed once I know how much my glider will weigh.

That will easily surpass the melting temperature of coal by a good amount but it would probably be easier to just melt it in a disposable pan.

Thats cool I am not sure if you can get it hot enough to melt it easily It takes about 600 farenheit I believe and I am not sure how hot an actual stovetop will get a pan. However an actual fire should get hot enough to melt it.

Actually if you have some access to clay you could design a mold and find something to fill it with to create perfect sized projectiles easily. I would think that if you can get some lead would be easy because of a low melting point but also candle wax would be fun and both are reusable as long as ...

I understand its just the terminology I am used to using. I changed the wording so as not to make anyone angry.

Edit to clarify my plans for Pimpmann22. The current plans I have are 3 or 4 inch diameter chamber at 2 or 3 feet long depending on the prices with about a 5 or 6 foot barrel. I ...

The design in my head is a 3 inch, at wide end, oval with fold out wings so the actual glider wont be that big and I could probably get all the circuitry in a design less than 2inches wide. But thats my project for next semester this semester I want to stick with simpler designs. Sorry about calling ...

How hard is a piston valve to make I am pretty short on tools as I live in a studio near campus so all my tools were left at home. Mainly I have my pc repair kit with my soldering/electronics tools on me which most of is designed for finesse work not large scale. I might be able to get access to ...

I am currently planning on building a pneumatic projectile launching device. However, first, I have a few questions for some of the more experienced people. First, on the idea of interchangeable barrels, does having screw on barrels effect the power of ability of the gun. I plan on using a 3 or 4 ...