Search found 228 matches

by mrfoo
Tue Jul 26, 2022 12:56 pm
Forum: Ammo & Parts
Topic: Great video testing spud gun failure/safety (ThebackyardScientist)
Replies: 4
Views: 1515

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: 904

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: 721

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: 1114

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...
by mrfoo
Tue Apr 26, 2022 11:25 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Convert a Gas refill cylinder to an air cylinder?
Replies: 7
Views: 1114

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

At a guess, that can's gonna be super thin, which would make modding it pretty difficult. I'd be more tempted to look at a discarded 60l oxygen canister or maybe a fire extinguisher CO2 recharge canister. Rather than modifying a canister, try talking to a local machinist, see if they can make up a t...
by mrfoo
Sun Nov 28, 2021 8:33 am
Forum: Off-Topic Hobbies
Topic: OK, it's not a spud launcher
Replies: 1
Views: 1375

OK, it's not a spud launcher

But it's pretty damn next level.

by mrfoo
Fri Oct 01, 2021 9:55 am
Forum: BB, Airsoft, and Pellet Guns
Topic: What is 0000 buckshot used for?
Replies: 2
Views: 1232

Re: What is 0000 buckshot used for?

It's used for shooting big mother buckers.
by mrfoo
Sun Aug 29, 2021 5:05 am
Forum: Hybrid Cannons
Topic: Thoughts on my piston valve design
Replies: 41
Views: 15915

Re: Thoughts on my piston valve design

> Obviously the downside is the spring isn't variable so a different spring would be needed for a given mix.

A threaded boss at the rear can increase or reduce preload on the spring within a certain range, although this will also reduce spring travel.
by mrfoo
Mon Aug 16, 2021 5:45 am
Forum: Off-Topic Hobbies
Topic: I CAN HAZ MILING MACHIEN?
Replies: 4
Views: 2673

Re: I CAN HAZ MILING MACHIEN?

So, spent some time stripping down a bit. Managed to unblock the tooling and the Z axis, (hooray for hand winches), loking at the scraping marks on the slideways and gibs I thought to myself "that's been rescraped", but given the way the gibs fit, I'd be surprised if it's done many hours from new. D...
by mrfoo
Sat Aug 14, 2021 1:06 am
Forum: Off-Topic Hobbies
Topic: I CAN HAZ MILING MACHIEN?
Replies: 4
Views: 2673

I CAN HAZ MILING MACHIEN?

It's been a while that I've been looking for a smallish milling machine to go with my smallish lathe(s). Yes, I am aware that the chinese make some fairly capable small milling machines. But I simply don't like them. Horrible yucky plastic tat. Id far rather something made of great big chunks of cas...
by mrfoo
Thu Jun 17, 2021 5:40 am
Forum: Combustion Cannons
Topic: Trouble with oxy/acetylene mix
Replies: 6
Views: 2865

Re: Trouble with oxy/acetylene mix

No idea how to resolve the problem. Just posting to say "Whoah what the fuck you're clearly my kind of absolute fucking maniac" 🤘
by mrfoo
Tue May 25, 2021 12:06 am
Forum: Off-Topic Hobbies
Topic: Two Italian WW2 helmets found
Replies: 5
Views: 3197

Re: Two Italian WW2 helmets found

That's pretty cool.
by mrfoo
Thu Apr 22, 2021 2:15 pm
Forum: Hybrid Cannons
Topic: Xtreme-patator
Replies: 11
Views: 5112

Re: Xtreme-patator

Nice. Comme dit hector, le cuivre ne risque pas d'aimer cette utilisation. Tube acier sans soudure Ø20, ep2 te donnera Øint de 16mm, ce n'est pas trop cher - https://lamtechno.com/tube-acier-de-precision-e235n-rond-sans-soudure-cintrable/90-381-tube-acier-sans-soudure-cintrable-diametre-20.html#/23-...
by mrfoo
Thu Apr 01, 2021 12:26 am
Forum: Pneumatic Cannons
Topic: Pressure rating for Coaxial cannons
Replies: 12
Views: 5032

Re: Pressure rating for Coaxial cannons

Good question. The force being applied to the barrel will be compression, rather than tensile, and PVC (like many materials) is stronger in that respect. Tensile strength of rigid PVC, 34 … 62 MPa, Compressive strength 55 … 89. So in that respect, you're probably OK. However. These figures are signi...
by mrfoo
Sun Mar 28, 2021 6:23 am
Forum: Hybrid Cannons
Topic: Large hybrid
Replies: 10
Views: 5578

Re: Large hybrid

Norguns wrote:
Sat Mar 27, 2021 11:56 am
I get what you are saying, I might not get any real velocity gain from it. That being said, the entry fee for evacuating the air from the barrel is low on my setup and i might play with it at a later time.
You owe it to yourself to try :)