I read spudblaster's hybrid fueling 101 which is stickied in the hybrid cannon forum. He told us how to do it, so I'll reiterate it here. I don't bother with any of this math myself because HGDT was thunk about so I don't have to do any thunking about fueling and I can just focus on my design. Here'...

SpudBlaster15, I'm dying to know what you have in mind. Spill the beans! I don't have access to much space at the moment and it has been a long time since I touched any spudgun related building materials and tools, so I might just throw together a quick, easy QEV pneumatic to see if I can jumpstart...

It looks awesome. Only question I have is how does he vent if before the next shot?

I bought the Ceda S and just shot it across the living room. Hoooly crap! I knew what to expect in terms of FPS from reviews online, but I was still totally surprised at how fast it shoots. My kid's nerf blasters just sort of float the dart across the room, and this thing rockets them in a straight ...

LOL. Cool video! If you want to blow your own mind, build a metered propane cannon with a chamber fan. Probably get around 120 meters per second with pretty much perfect reliability.

Also, if you decide to make a combustion cannon, there is a particular fuel that you should avoid at all costs. Almost every time a combustion cannon explodes in someone's hands, it's because they used propain instead of propane.

That's looking great! I believe I see some beautiful looking materials. Is that Delrin, UHMW, aluminum, steel, and brass? Those are the things dreams are made of.

Nice work. I've always loved Tech's QDV style and it's good to see a nice cannon made with it. Any chance of internals pics? Maybe a video seeing it shoot? Is the chamber stainless steel? It looks nice.

Go to the thread below and scroll down a bit. Click the zip file for GGDT. It stands for Gas Gun Design Tool. The other one is HGDT (Hybrid Gun Design Tool). Hybrid's are pressurized propane and air cannons and are a different beast altogether. Anyway, get familiar with GGDT and entering inputs for ...

From the perspective of a skilled tradesman, I can see how one would prefer quality equipment. But from the perspective of a hobbyist like us, even 0.1mm precision would be fine for anything we do. 0.1mm is about .004", and a standard machined tolerance for most parts is +/- .005". You could just ma...

Keep in mind I'm the guy who just puts numbers on paper and then expects everything to somehow work out in the shop. If I tried to machine my last cannon myself, regardless of equipment used, there'd be enough aluminum scrap to form an extinction level-sized asteroid.

As long as the o-rings seal, the darn thing will work. The benefit of making parts yourself is you can just tweak them until they fit without caring much what the final dimensions are. If making drawings for someone else to make your parts, then of course you need to watch the tolerances and make s...

That's actually pretty good. It actually looks exactly like many sketches I've seen over the years in machine shops. A lot of places work off of sketches just like that. The information content is what matters, and as long as they know what to do, then the drawing is just fine.

I weigh just about 185lbs...hmm. Hey D_Hall, I'd like to apologize for my smart ass comment I made 10 years ago to you about how I thought "UHMW" should be called "UHMW" without the "PE" at the end. I had a job where people used that stuff and they called it UHMW, so I thought I was Mr. UHMW or some...

Watch out with that. I'm thinking your tube might have a weld seam since it's just a structural steel tube, right? Only seamless tubes should be used with high pressure and only then might the calculations provide some value. You often can't see the seam unless you look closely, and even then you mi...