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 71 users online :: 4 registered, 0 hidden and 67 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

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

Capacitor ?

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
Sponsored 
  • Author
    Message

Capacitor ?

Unread postAuthor: Demon » Tue Jun 02, 2009 7:01 pm

Did anyone already tryed to make a capacitor bb/paintball gun? I just blew up mine and i has some pretty impressive POW !

Let me tell you how(lol): I was setting a 5 volts regulator for my pic microcontroller, but to clean the signal i was using either too low volt rated capacitor or too high wall mounted power adaptor( 24 volts output)... and the capacitor was not in the right polarity...

When i pluged the adaptor, nothing appened first because there was a bad contact, but when i shaked my breadboard, i heard "VIIIIIIIII" and i was like "Holy ****" (i knew that there was a short circuit). when i hurried to my adaptor, KA POW! The capacitor burst disk failed ( yes, there is one ) and my hears started whistling...

Just to give you an idea of its power:

http://www.youtube.com/watch?v=_WheLp0RdLQ

There are 6 mm capacitor so you can just glue an airsoft on an put it in a barrel.

For who dont know, you can get very high voltages from a bigger capacitor (minimum 3000 uf) to make it blow up(the tinier one), only charged by a 9 volt battery(takes 5 secs)

Dont count on me to try that, i am out of spudguning.

What do you think?

http://www.youtube.com/watch?v=Fx_axiO0l20

http://www.youtube.com/watch?v=MWelgZTz ... re=related
  • 0

User avatar
Demon
Colonel
Colonel
 
Posts: 743
Joined: Sun Apr 13, 2008 8:46 am
Reputation: 0

Unread postAuthor: TurboSuper » Wed Jun 03, 2009 11:09 am

Seems like a nifty idea to try if you have alot of spare capacitors lying around, but it doesn't seem very powerful.

Still, I can see the entertainment value of a fully automatic cap launcher :P
  • 0

"If at first you dont succeed, then skydiving is not for you" - Darwin Awards

TurboSuper
Brigadier General
Brigadier General
 
Posts: 986
Joined: Thu Jun 16, 2005 1:44 pm
Reputation: 0

Unread postAuthor: Technician1002 » Wed Jun 03, 2009 5:40 pm

Electrolytic capacitors have an electrolyte in them (surprise). When the polarity or voltage causes a failure, the electrolyte overheats. This causes steam. This is just a steam explosion.

Small capacitors don't have a rupture disk. They have a rubber seal and will often blow the rubber plug resulting in ejection of the aluminum can. Larger ones that are used in power supply and higher power applications are more likely to have enough power applied to cause a steam explosion. These have a rupture pattern embossed into the top of the aluminum can so the top of the can bursts instead of launching the capacitor off the leads.

This article goes into the chemistry in the capacitors so you know what you are exposed to when these rupture.
http://en.wikipedia.org/wiki/Electrolytic_capacitor
  • 0

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

Unread postAuthor: rp181 » Wed Jun 03, 2009 7:48 pm

larger capacitor's also have rubber vent type holes, and the steam leaks through there sometimes.
  • 0

User avatar
rp181
Brigadier General
Brigadier General
 
Posts: 1090
Joined: Thu Dec 13, 2007 8:47 pm
Reputation: 0

Unread postAuthor: jimmy101 » Thu Jun 04, 2009 1:49 pm

At high enough voltages and currents the whole thing will pretty much deflagrate (burn), especially non-electrolytic types.

Same with small wattage resistors. They make great ghetto squibs for pyrotechnics.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3130
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Unread postAuthor: Hotwired » Thu Jun 04, 2009 2:11 pm

I remember it was either a physics or more likely an electronics class where the teacher was demonstrating polarised electrolytics charged in reverse since charging them the right way round wasn't all that interesting.


Fun stuff unless you get some of that gloop on you. On which note I'd say blown caps would be a ghastly propellant.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: Demon » Tue Jun 23, 2009 2:43 pm

When i accidently blew up my capacitor(100 uf), the metal failed, not the rubber...
  • 0

User avatar
Demon
Colonel
Colonel
 
Posts: 743
Joined: Sun Apr 13, 2008 8:46 am
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: Technician1002 » Tue Jun 23, 2009 3:56 pm

Demon wrote:When i accidently blew up my capacitor(100 uf), the metal failed, not the rubber...


Metal vaporizes from over current, such as shorts, internal arc, etc. Overvoltage, reverse polarity, AC, etc often results in electrolyte overheating resulting in steam explosions.
  • 0

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

Unread postAuthor: Hotwired » Tue Jun 23, 2009 4:30 pm

I think Demon means the scored burst pattern in the cap blew instead of the rubber plug.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: Technician1002 » Tue Jun 23, 2009 7:48 pm

Hotwired wrote:I think Demon means the scored burst pattern in the cap blew instead of the rubber plug.


Most likely correct. Some cheap ones are not scored and either eject the entire case or blow out the end. In relation to other projectile propulsion methods, this is very expensive and requires plenty of electrical power to generate the steam. The power is limited as most are designed to fail gently at relatively lower pressures. The amount of moisture is limited so even if it fails at higher pressure, the steam expansion is limited. The cap being removed by steam is spectacular, but overall, it's not great for launching stuff other than the cap itself.
  • 0

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

Return to Combustion Cannon Discussion

Who is online

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

Reputation System ©'