Torque

mxtabs which has a massive database was also shut down due to legal issues i believe, but recently they switched owners and it is scheduled to come back with summer so keep an eye on that if you're desperate.

If you are using a pre-cut one were out of a box it has threads just drill a hole, the size of the sharder valve, teflon the screws, and then screw it in. If your using one that you cut out of a bike tire, ect., just do pretty much the same thing. Drill a hole the size of the valve and slide it in from the back end of the end cap. Either way I find it easy to just use an end cap. I have used it on all my home mades and its worked fine.

You could also go to a shop and buy or get free valves for car tires, thats what i did. I went to a repair shop and the guy just gave me several for free, as they have them lying around usually. To install those kinds of valves you simple drill a hole and push them in to create a seal, no sealant/glue etc. is required at all.

I really feel bad about ressurecting this thread but I really want to learn more about this amazing piece of machinery. Have you gotten it firing yet? If so what are ranges? Again I feel bad about this, but I saw you were active recently.

I appreciate your interest in my homemades, but unfortunately i have not worked on it recently at all for various reasons. One of which is becoming disinterested in the overall design and the spring/plunger method of firing darts seemed to me boring. The way I designed this gun is also very finicky and complicated to work on, as everything must be lined up perfectly or else part A doesn't seal properly or part B jams and keeps part C from functioning properly etc.

If I do work on it and make any significant improvements then I'll definitely post in this thread to inform you all. The gun essentially does work, it cocks, loads a shell, "fires", ejects the shell and recharges the plunger spring while loading a new shell however it doesn't fire darts because i screwed up some of the tolerances on the breach parts so they leak the air instead of using it to push the dart out of the shell/barrel. As of right now if i decide to work on it i will have to fabricate a new spring retainer, plunger head, and breach. The plunger head broke because there is so much pressure behind the spring forcing it into the pin that retains it when cocked and the spring retainer broke simple because i made it too thin for the pressure it has to handle. Both of those parts wont be had to make its just the breach that would be difficult to fix.

What i want to know is how far apart the bullets are going to be. Like, from the most left bullet to the most right bullet? Other than that, i hope to see it working.

I'm not quite sure i know exactly what you're talking about. If you mean what is the spread as in how the pellets from a real shotgun spread apart at a distance, then the answer is that they don't. This isn't a shotgun in that kind of sense, it just fires 1 dart at a time. If you wanted you could split the dart into thirds, quarters, halves, etc and then load them into the shells and that would create a spread as others have done but unmodified its just like any other spring gun like a SNAP etc. Also even if it did spread, that number will vary with the range you are firing at. At close range the spread will be vary limited and at a farther range the spread will generally be greater.

What size pipe are you using for the airtank?

He's using 1 1/2" SCH 40 pipe going into a coupling and then a reducer bushing that converts from 1 1/2" to 1" pipe i believe. You can see the label on the air tank in the second picture of this thread.

Also Sponge_Nerfer, the piece of metal at the end of your blow gun can actually unscrew from the rest of it. (The small piece of threaded pipe with 2 holes in it right below the hook that you cut off) It might be worth taking this off as it could improve airflow as it increases the ID of the air outlet. If it does improve airflow then the pilot air will leave your union chamber faster, the burst discs will take less time to over pressurize and rupture, and there may be a slight increase in overall actuating time and performance from your valve. Or you could take it off just to make the handle more compact, I was just informing you that it was removable as i did not know that piece was removable on my blow gun and after i removed it, i found many uses for the threads that were exposed.

This is sort of off-topic, but Torque, can you give us a brief update on that "Boomstick" of yours?

I really stopped working on my boomstick homemade mainly because I was tired of spring/plunger designs and with school didn't have very much time. I basically became uninterested. I might be able to get up some pictures of my spring actuated ball valve and bazooka looking homemade sometime this weekend or next week though that way people can see real versions of what the valves look like incorporated into a nerf gun.

Sponge_Nerfer: I'm not sure that aluminum foil would be the best substance for a burst disc as it might tear when you're trying to put it into the union. You might be able to use layers of something like plastic wrap though, because that way you can adjust the pressure at which the valve fires. For instance if 1 layer of plastic wrap bursts at 10 psi and you needed a higher pressure, you could simply add more layers to get it to burst at your desired psi. Balloons also might be worth trying if they're stretched tight enough in the union. (only a section of material from the balloon, not the whole thing.) Both plastic wrap and balloons seem fairly air tight when used right, i have never tried aluminum foil though so it might be interesting to see if you can get it to work.

Burst discs are also used in hybrid spud guns but materials like the plastic from coke bottles are used which i have heard burst at around 150 psi. This of course is not made with pvc pipe but metal unions and threaded pipe from something like galvanized steal pipe. Also propane or another fuel is mixed with air inside the chamber and a spark plug or other spark gap between screws etc. is used to ignite the mixture. When the disc ruptures the desired projectile is forced out of the barrel. I have thought about making a similar device but using a disc that ruptures at a much lower pressure so it could be constructed from pvc pipe. I would then make multiple cannisters with a union/burst disc, spark plug, and pipe/end cap and use these as shells. The problem with this is they would really be too large to be used for normal stefans but might have a more practical use for a grenade launcher style gun or a grenade launcher attachment to another gun. It may not be the most practical thing ever but having a muzzle flash and a loud boom would definitely make a cool factor about it.