As D_Hall says, PVC is a bit sketchy*, and (as with all pipes), pressure rating goes down as diameter goes up. Schedule 80 is better than 40, but it doesn't mean twice the pressure, you get maybe a third as much again. With a longer barrel, you're going to be exposing the pipe to more pressure, and ...

I'm not sure that the speed of sound is an overly useful measure. As I understand it, and I've probably totally misunderstood, even in a "conventional" firearm, the combustion is subsonic even though the actual projectile velocity can be at least supersonic; and that it's pressure and the time the p...

Believe me, you really don't want me to join.

Yeah, but they are pretty (read "very") expensive, especially in the sizes you're looking at. Expensive enough that it's maybe worth talking to a local machine shop.

How about piloting a QEV with a smaller solenoid? That should provide a useful boost in performance without having to build your own valve.

nice gun and great work How, in the name of all that's holy, could you possibly know that? The photos are dead, the videos are private, and apart from one post in 2019 the whole thing hasn't been touched since you were literally in diapers. SpudFarm themselves haven't posted since 2017. Your contin...

Oh, you got banned from a forum? Whatever could have caused that?

The website does not work because the entire xinventions site is dead. the page, including photos, is available through the wayback machine, but as they were selling plans, and the people who ran xinventions are not the people you are talking to here , you're unlikely to get the plans by asking here.

OK, I'm gonna hit you again, perhaps less gently. Quinn. What you are doing is not polite, and at best is creating cleanup work for the moderators. Generally speaking, forums have their own rules, the ones for this one are found here , but there's a more general set of rules that are assumed to be g...

OK, you're young, and you're enthusiastic. I'm old, and cynical, and jaded. Here's some advice. This is what's known as a "forum", and it's not even a particularly active one, even by 2024 standards. It's not instatwatbotik. There aren't 50 trillion twunts watching it for the latest news, poised rea...

It's almost as though we're being hit with someone testing AI forum bots.

Are you an AI? Because that really, really reads like an AI response to "how to make a pjeumatic speargun"

[edit] Beaten to it by JSR, as usual.

Back in the day, we had little diesel aero engines that ran on a mix of ether and castor oil. A good source for ether might be one of those easy-start cans.

Well that was a load of word salad conspiracy bollocks. I feel dumber from having merely skimmed it. Thanks a bunch.

[edit] This post was made in reply to some absolute crap that jrrdw just removed, and not in reply to what's now visible up above.