Search found 1872 matches

by D_Hall
Fri Mar 06, 2020 4:29 pm
Forum: Miniature Guns
Topic: Dual Camera System to enhance combustion weapons.
Replies: 13
Views: 3362

Re: Dual Camera System to enhance combustion weapons.

Yes, I found this topic a couple years late and it took me a bit to digest it.... ...But I don't think there's much to the "piling" phenom. It allows you to boost pressure, yes, but for a significantly smaller available volume in the combustion chamber. The result would be higher pressures, but decr...
by D_Hall
Thu Mar 05, 2020 10:55 pm
Forum: Miniature Guns
Topic: Dual Camera System to enhance combustion weapons.
Replies: 13
Views: 3362

Re: Dual Camera System to enhance combustion weapons.

[nevermind... hmmm... how does one delete a post with the new forum software?]
by D_Hall
Thu Feb 13, 2020 11:59 pm
Forum: Ammo & Parts
Topic: Low-friction/Specialty Ball Valves?
Replies: 11
Views: 1667

Re: Low-friction/Specialty Ball Valves?

You're not going to get much lower friction than teflon seals, but they can still be a bear to turn. Ball valves simply aren't designed for quick/easy motion.
by D_Hall
Mon Feb 10, 2020 1:40 am
Forum: Ammo & Parts
Topic: 3D printed golf ball dart tails (image attached)
Replies: 1
Views: 562

Re: 3D printed golf ball dart tails (image attached)

It will probably work, yes. But I think it's also a lot tougher than required. Put it this way... I've had decent luck with nothing more than a 2" deck screw. Drill a small hole into the ball. Screw the deck screw in. Done. Doesn't look nearly as cool, but it works.
by D_Hall
Sun Jan 26, 2020 1:09 pm
Forum: Ammo & Parts
Topic: They aren't cheap but...
Replies: 2
Views: 774

Re: They aren't cheap but...

You'd need to build a sabot for them. At that point, you might as well build your own projectile (for less money).
by D_Hall
Sun Jan 26, 2020 1:06 am
Forum: General How-To & Discussion
Topic: Describe the ultimate potato cannon
Replies: 10
Views: 2274

Re: Describe the ultimate potato cannon

I swear to all things holy and not, if I had the money lying around, I'd build it. I would actually be crazy enough to go through with building this thing. It would be absolutely hilarious. Let's just say that I didn't come up with the performance specs on a whim. I was asked by some folks if it wa...
by D_Hall
Sat Jan 25, 2020 2:00 pm
Forum: General How-To & Discussion
Topic: Describe the ultimate potato cannon
Replies: 10
Views: 2274

Re: Describe the ultimate potato cannon

I confess that I've not really thought about the details of the valving since I doubt I'd get the funding to build such, burst disks work well, and burst disks are a negligible cost in the Big Picture. The point being that whimsy aside, the gun would almost certainly use burst disks. With the valve ...
by D_Hall
Fri Jan 24, 2020 2:22 pm
Forum: General How-To & Discussion
Topic: Describe the ultimate potato cannon
Replies: 10
Views: 2274

Re: Describe the ultimate potato cannon

Bore: 24 inch. Barrel length: 60 feet. Break action. Barrel on a carriage system such that the breach can be opened/closed without raising/lowering the CG of the barrel. This means easy movement despite the size. Valved would, of course, be nice, but I've had good luck with burst disks. Propellant: ...
by D_Hall
Sat Dec 14, 2019 12:16 pm
Forum: Pneumatic Cannons
Topic: Syncing of multiple valves.
Replies: 10
Views: 1104

Re: Syncing of multiple valves.

How much pressure and what are the dimensions you are looking at for barrel and chamber? You mentioned 1" ID for the barrel. How long and what size is the chamber? Also, what ammo? Right now I'm still in the pondering stage. I'm thinking about stuff, but I've purchased nothing and may never actuall...
by D_Hall
Sat Dec 14, 2019 12:28 am
Forum: Pneumatic Cannons
Topic: Syncing of multiple valves.
Replies: 10
Views: 1104

Re: Syncing of multiple valves.

Anatine Duo wrote:You could build a test rig (lay a flat plate over both valve exhaust ports and check out how much rotation it gets lol)
Alternatively, just defeating one pilot (so THAT valve) never opens, measuring a few shots, and then comparing them to dual valve performance should give you a real-world result.
by D_Hall
Sat Dec 14, 2019 12:26 am
Forum: Pneumatic Cannons
Topic: Syncing of multiple valves.
Replies: 10
Views: 1104

Re: Syncing of multiple valves.

Connect both valves to a single pilot maybe? That's certainly the plan, but all it takes is a bit more friction on one valve than the other and one will open before the other. Further, as the first piston/diaphragm slides back, it will momentarily pressurize the pilot thereby delaying the second va...
by D_Hall
Fri Dec 13, 2019 11:50 am
Forum: Pneumatic Cannons
Topic: Syncing of multiple valves.
Replies: 10
Views: 1104

Syncing of multiple valves.

Situation: I'd like to build a 1" bore pneumatic with full flow capability. Sure, I could make my own valve but I'm a lazy bum with other hobbies that take time too. With that said, the largest QEV I've seen that is quick/easy/cheap/etc. is the 3/4" QEVs from McMaster. Yes, there are other valves ou...
by D_Hall
Thu Nov 21, 2019 10:05 pm
Forum: General How-To & Discussion
Topic: Spud gun exploding
Replies: 14
Views: 2606

Re: Spud gun exploding

Djkitten wrote:Since I couldn’t find any solenoids larger than 1 inch, I can’t really change them to a larger size.
You didn't look very hard. They're spendy, but they're out there. Search for "commercial irrigation valve".
by D_Hall
Thu Nov 21, 2019 10:04 pm
Forum: General How-To & Discussion
Topic: Spud gun exploding
Replies: 14
Views: 2606

Re: Spud gun exploding

It is all pressure rated. Also thanks for the tip the only thing I have to replace are the elbows, I will made one those spacers soon! Thank you for the suggestions:) In the spud gun world a lot of newbs seem incredulous when you comment on the choice of PVC. "It is all pressure rated" is a common ...
by D_Hall
Mon Nov 18, 2019 1:53 am
Forum: Combustion Cannons
Topic: Spud gun powered by cooking oil?
Replies: 11
Views: 2256

Re: Spud gun powered by cooking oil?

I would try to simplify, and if the liquid fuel complicates, use gas to load lighters, pure butane, which is already gasified and you can measure it quite accurately. It is my idea only. :roll: At the pressures he's talking about, butane is no longer gasified. Gonna need to go with something lighte...