Search found 239 matches

by mrfoo
Fri Dec 02, 2022 1:14 pm
Forum: General How-To & Discussion
Topic: How do you convert in3 into in2
Replies: 2
Views: 349

Re: How do you convert in3 into in2

Boyle's Law. Not Susan Boyle. For a given mass of confined gas at constant temperature, pressure multiplied by volume will be constant. So for a starting state at pressure P₁ with chamber volume V₁, and a compressed state P₂ with final chamber volume V₂ : P₁V₁ = P₂V₂ This gets combined with Charles'...
by mrfoo
Sun Nov 13, 2022 1:42 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"
Replies: 18
Views: 12827

Re: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"

Haha no. bought the inverter to run the mill, which is 380v three phase, it turned up and the documentation said it could run 4 separate motors (one at a time, obvs). The mill has a 2 speed dahlander motor, so effectively 2 motors, and the lathe also has a 2 speed dahlander motor, so 2 more motors, ...
by mrfoo
Sun Nov 13, 2022 1:49 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"
Replies: 18
Views: 12827

Re: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"

Glad to hear it was something simple. I would have left the resistor on a start capacitor, as it will live with charge on it - it's a shock hazard. there's also the risk of more arcing on the centrifugal switch as it switches, which could mean more wear and tear. It's no biggie, though, just be very...
by mrfoo
Sat Nov 12, 2022 5:35 am
Forum: Hybrid Cannons
Topic: Is there a more active website than this?
Replies: 8
Views: 705

Re: Is there a more active website than this?

You think it's bad here? Try getting involved in making pulsejets :P "the death of the forum" has been ongoing for a while, with several technologies vying to take its place. All sorts of gamifyng and the like, and it pulls users from forums with glitz and pizzaz, but the problem as I see it is that...
by mrfoo
Fri Oct 28, 2022 1:31 pm
Forum: General How-To & Discussion
Topic: Is spudding dead?
Replies: 116
Views: 59030

Re: Is spudding dead?

I like that idea, Hector.

There's a few people on here with machine tools (I'm one), maybe some community machining of specific parts? Maybe a design for a specific high performance hammer valve, something like that?
by mrfoo
Thu Oct 20, 2022 12:41 pm
Forum: General How-To & Discussion
Topic: Is spudding dead?
Replies: 116
Views: 59030

Re: Is spudding dead?

Quite. And to be honest, the addition of the little "thumbs up" icon at the top of every post does little to help. Gamification of social interaction, it fucking sucks.
by mrfoo
Fri Sep 16, 2022 12:27 pm
Forum: Pneumatic Cannons
Topic: Access Old Threads?
Replies: 5
Views: 1895

Re: Access Old Threads?

jackssmirkingrevenge wrote:
Fri Sep 16, 2022 10:51 am
I don't suppose there's a way for PCGUY to automatically update all the broken links?
I've been through this before, and frankly, it's an awful lot of work and a proper pain in the rear to do correctly.
by mrfoo
Thu Sep 08, 2022 12:46 pm
Forum: Pneumatic Cannons
Topic: Access Old Threads?
Replies: 5
Views: 1895

Re: Access Old Threads?

by mrfoo
Tue Sep 06, 2022 1:23 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Hammer & QEV Valve Questions
Replies: 5
Views: 2009

Re: Hammer & QEV Valve Questions

With a standard hammer valve the hammer has to open *and hold open* the entire valve that's going to be used to flow the air you're using for propulsion. As pressure and bore size go up, you'll need more and more hammer force to open the valve. A QEV + hammer valve reduces the hammer force required ...
by mrfoo
Fri Aug 26, 2022 8:47 am
Forum: SpudFiles Discussion
Topic: Youtube Changes Coming July 23, 2021
Replies: 2
Views: 4241

Re: Youtube Changes Coming July 23, 2021

That's not entirely true, as I understand it Users with unverified accounts may only post videos less than 15 minutes long. Verified accounts can post videos up to 12 hours long. The cynic in me says it's nothing to do with reducing the amount of time people spend on the site, as that would be utter...
by mrfoo
Sun Aug 21, 2022 10:16 am
Forum: Pneumatic Cannons
Topic: 3D printed internal valve trial
Replies: 7
Views: 2545

Re: 3D printed internal valve trial

Bearing in mind that I know bugger all about 3d printing apart from what Ive read on line, I think I'd probably be a bit worried about the housing splitting along the lines between layers. Otherwise, it looks proper good and very much the kind of thing I'd machine.
by mrfoo
Tue Jul 26, 2022 12:56 pm
Forum: Ammo & Parts
Topic: Great video testing spud gun failure/safety (ThebackyardScientist)
Replies: 4
Views: 3892

Re: Great video testing spud gun failure/safety (ThebackyardScientist)

Not sure if there was air in the line behind the water, but an interesting result. Definitely, he was pressurising with gas. So there was all the stored pressure of the gas in the line to deal with. Best way to do it is with a grease gun, they go up to stupid pressures (I've done hydroforming with ...
by mrfoo
Wed May 25, 2022 1:37 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Steel galvanized pipes as pcp rifle air chamber
Replies: 4
Views: 2684

Re: Steel galvanized pipes as pcp rifle air chamber

1500 psi is above the rated pressure for the pipe, which is closer to 750psi. Although it *probably* won't unexpectedly burst at that pressure, but you've blown away any safety margin you have, so any minor damage could be catastrophic. But rather than the pipe itself, I'd be very worried about thre...
by mrfoo
Tue May 10, 2022 5:45 am
Forum: Pneumatic Cannons
Topic: I need of dire help (Air Solenoids valves)
Replies: 2
Views: 2342

Re: I need of dire help (Air Solenoids valves)

Can't help you with solenoids except to say that they're probably orders of magnitude too slow for what you want. I can't even necessarily help with the latter part, but I can give some gut feel. Would like to find out about some new stuff if I can, maybe something along the lines of how much PSI sh...
by mrfoo
Wed Apr 27, 2022 6:52 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Convert a Gas refill cylinder to an air cylinder?
Replies: 7
Views: 3353

Re: Convert a Gas refill cylinder to an air cylinder?

What I meant was I'd drill a hole at the end of the gas canister and then epoxy on the Schrader valve in the end for it to accept air instead of gas. But your saying that it's impossible? Nothing's impossible. But at a guess, the walls of that canister are no thicker than 0.5 mm or so. That's super...