Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 61 users online :: 4 registered, 0 hidden and 57 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

"Offtopic-posts-topic" NSFW

All non-spudgun related discussion goes here such as projects, theories, serious questions, etc. All "off-topic" posts (aka useless posting, determined by moderators) will be removed.
Sponsored 
  • Author
    Message

Unread postAuthor: Zeus » Sun Mar 06, 2011 3:11 am

I'd link to Encyclopedia Dramatica, but the ads can be a little "distracting", it's a most excellent site though.

It's very informative about computer games, the definition of Resident Evil 4 & 5 was spot on.
  • 0

/sarcasm, /hyperbole
User avatar
Zeus
Major General
Major General
 
Posts: 1422
Joined: Tue Oct 27, 2009 7:34 pm
Location: 'Straya, C*nt
Reputation: 2

Unread postAuthor: Lockednloaded » Wed Mar 09, 2011 10:40 pm

not off-topic, but not deserving of its own thread:

I've been looking at some accessories for my ratary tool, This in particular caught my eye, what do y'all think? would it be very useful for spudding?
  • 0

User avatar
Lockednloaded
Major General
Major General
 
Posts: 1558
Joined: Thu Sep 03, 2009 9:38 pm
Location: Texas, USA
Reputation: 0

Unread postAuthor: irisher » Wed Mar 09, 2011 11:03 pm

I got one of those recently. It is VERY handy for machining aluminum but you should be aware that the accuracy is absolutely terrible. Even with small drill bits, the entire thing will flex and end up all over the place. I really do like mine but do not plan any precision work.
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: Lockednloaded » Wed Mar 09, 2011 11:11 pm

I'm not making jewelry, art, or precision parts; I just need something steady for making a few crude, custom parts
  • 0

User avatar
Lockednloaded
Major General
Major General
 
Posts: 1558
Joined: Thu Sep 03, 2009 9:38 pm
Location: Texas, USA
Reputation: 0

Unread postAuthor: irisher » Wed Mar 09, 2011 11:19 pm

It should work for crude parts but I would advise messing around on a piece of scrap first to get an idea of how it flexes. Also beware the "crowsnest"; The telescoping aluminum that serves as the backbone to the stand will collapse at the least opportune time if you are fiddling with power cord and drive your hand into any drill bits you happen to store there.I got a drill bit snapped off inside of by hand because of that. :(
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: SpudBlaster15 » Thu Mar 10, 2011 4:53 am

*Walks into the room whistling suspiciously*

Hey, I made a somewhat spudding related video today. It was going to consist entirely of spudding clips, but SWIM came over and insisted that we use a bunch of his footage as well. :roll:

[youtube]http://www.youtube.com/watch?v=Dwl5bjLPgPw[/youtube]
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: mark.f » Thu Mar 10, 2011 6:50 am

Nice! Although you'll have to point out the HE clips because I thought I saw mostly flash (although I'm not an expert at this at all).
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Sponsored

Sponsor
 


Unread postAuthor: Ragnarok » Thu Mar 10, 2011 12:27 pm

SpudBlaster15 wrote:Hey, I made a somewhat spudding related video today.

Hang on, isn't there some rule that says all compilation videos of explodey type things have to be set to the 1812 overture?
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5339
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 8

Unread postAuthor: jackssmirkingrevenge » Thu Mar 10, 2011 12:49 pm

with some more effort you could turn it into adecent beat ;)
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: JDP12 » Thu Mar 10, 2011 1:16 pm

JSR- thats awesome! haha highlight of my day so far..
  • 0

"Some say his pet elephant is pink, and that he has no understanding of "PG rated forum". All we know is, he's called JSR. "
User avatar
JDP12
Major General
Major General
 
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm
Reputation: 0

Unread postAuthor: ramses » Thu Mar 10, 2011 3:50 pm

Were you going for thermobaric on any of those videos? I believe I saw someone acheive actual detonation and film it with an ex-f1...
[youtube]http://www.youtube.com/watch?v=7dW1qkBg8sM[/youtube]

Almost makes me wish I had my EX-f1 again
  • 0

POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
User avatar
ramses
Major General
Major General
 
Posts: 1679
Joined: Thu May 29, 2008 6:50 pm
Reputation: 3

Unread postAuthor: SpudBlaster15 » Thu Mar 10, 2011 10:10 pm

Nice! Although you'll have to point out the HE clips because I thought I saw mostly flash (although I'm not an expert at this at all).


They were mostly flash, about half a dozen were HE (ETN and AN/Al).

Hang on, isn't there some rule that says all compilation videos of explodey type things have to be set to the 1812 overture?


It's pretty overdone IMO. While background music can be suitable for some videos, I prefer to actually hear the explosions themselves without interference from a soundtrack.

Were you going for thermobaric on any of those videos? I believe I saw someone acheive actual detonation and film it with an ex-f1...


Thermobaric yes, but there's a large difference between a thermobaric charge and a FAE device. Thermobaric charges are basically 'enhanced blast' explosives which contain excess fuel components and are designed to produce hydrogen gas and carbon monoxide as primary products, which will burn in atmospheric oxygen and create a secondary blast effect that strengthens the detonation wave. Adding excess aluminum powder is often used as well, as the high temperature aluminum will reduce oxygen containing products such as H<sub>2</sub>O and CO<sub>2</sub>, releasing large amounts of heat and producing the thermobaric effect.

A FAE device on the other hand uses a small high explosive bursting charge to disperse a liquid fuel such as propylene oxide or isopropyl nitrite sensitized heptane. The cloud of fuel is then detonated by a precisely timed HE charge placed within the radius of the dispersed liquid.

AFAIK, AnonymousUploads/NameWithheld is the only amateur who has successfully accomplished the latter. He's a contact of mine, so of course I've seen that video multiple times.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: ramses » Thu Mar 10, 2011 10:38 pm

Okay, I was under the impression that they were the same thing.

Regarding the fuel/air device, I honestly can't see it being that hard. I mean, set off one with a SCR and capacitor, 555 timer delay, set off the other.

With high speed video, one should be able to be correct the first time.
  • 0

POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
User avatar
ramses
Major General
Major General
 
Posts: 1679
Joined: Thu May 29, 2008 6:50 pm
Reputation: 3

Unread postAuthor: Technician1002 » Fri Mar 11, 2011 10:16 am

ramses wrote:Were you going for thermobaric on any of those videos? I believe I saw someone acheive actual detonation and film it with an ex-f1...


Almost makes me wish I had my EX-f1 again


Watching the video makes it clear that the burst charge was too small as the resulting fireball was both too rich and ignited too early. For a proper FAE, the fuel needed more air mixed and a little later ignition. With the proper dispersion gasoline works fine and is able to propagate a pressure wave.

A proper pressure wave looks like this on high speed;
[youtube]http://www.youtube.com/watch?v=IkeOHh8AoBM[/youtube]

Edit video is starting to be posted from Japan.. Wow!
[youtube]http://www.youtube.com/watch?v=JwWRMKf3dXs[/youtube]

[youtube]http://www.youtube.com/watch?v=jTMuXxviFYs[/youtube]

[youtube]http://www.youtube.com/watch?v=lDYbGyQGYgQ[/youtube]
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: SpudBlaster15 » Fri Mar 11, 2011 3:11 pm

ramses wrote:Regarding the fuel/air device, I honestly can't see it being that hard. I mean, set off one with a SCR and capacitor, 555 timer delay, set off the other.


The problem isn't so much programming the timing interval, but actually achieving a consistent firing delay. Traditional electric igniters for primary explosives are not very consistent in their timing, especially when manufactured using amateur processes. The delay between the activation of the circuit and the detonation of the main charge can vary by tens of milliseconds from setup to setup, and when we're talking about something as precise as the detonation of a dispersed liquid fuel cloud, these variations lead to difficulties.

I'd tend to think that a pair of EBW systems would be the only way to achieve 100% consistency. However, this will require multiple high voltage capacitors and charging circuits as well as large quantities of HV wiring, and is likely beyond the reach of all but the most serious and financially gifted energetics hobbyists.

Watching the video makes it clear that the burst charge was too small as the resulting fireball was both too rich and ignited too early. For a proper FAE, the fuel needed more air mixed and a little later ignition.


You do realize that a FAE does not simply involve ignition of the fuel/air cloud, but high explosive initiation resulting in near instantaneous DDT, right? Stoichiometry doesn't have nearly as much effect on overpressure or rate of reaction.

IIRC he used 9 grams of ETN to disperse 2L of fuel, which is very close to ideal given the VoD of this explosive. From the high speed footage, I estimate that the detonation wave propagated through more than 80% of the cloud, which is absolutely outstanding given the relative simplicity of the setup.

With the proper dispersion gasoline works fine and is able to propagate a pressure wave.


A pressure wave certainly, but not a detonation wave. Gasoline is designed to be highly resistant to detonation, as such events are highly destructive to ICE components. Detonating a reasonably sized cloud of gasoline/air mixture would require a massive initiator, which would defeat the purpose of a FAE entirely. Propylene oxide and IPN/Heptane mixtures are among the only fuels that are effective.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

PreviousNext

Return to Non-Spudgun Related Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'