My first combustion cannon....and what not to do with it.

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.

What type of n00b was (am) I?

Poll ended at Sun Mar 31, 2013 10:40 am

The crazy kind. Why did you do that when you knew what might happen??
1
100%
Um, you are not too bright, but neither am I. I have exploded cannons in the past.
0
No votes
You are the person Gippeto is referring to in his sig.
0
No votes
That looks fun! I am making one!
0
No votes
 
Total votes: 1
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SweatNTeflon
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Thu Feb 14, 2013 10:40 am

So, I built this about a year and a half ago. It's not anything too special and I am posting it more as a warning than to "Showcase" it :roll:

Stats:
Chamber- 4" sch 4 PVC, 30"
Barrel- 2" PVC, 60"
80mm chamber fan run off 12v battery held inside the body.
Ignition- Dual spark, run off an electric BBQ lighter.
Propellant: Metered MAPP gas

HGDT gives me an approximate FSP of 600 using MAPP gas. However, the little Devil on my shoulder told me (after using NO2 "safely") that an additional input of metered Oxygen was a good idea..... IT IS NOT.

Yes, Oxygen/MAPP is fun to shoot. No, it isn't meant for non-metal cannons :D

YouTube video of the cannon shooting with Oxygen/MAPP:
[youtube][/youtube]

This was before the last picture. Anyhow, I'd like to make an aluminum combustion cannon using MAPP/Oxygen. I know I'll be advised to "just make a hybrid", but since I am relatively new to all this, I'll take smaller steps, please.

That being said, any advice on how to build an Oxygen/MAPP combustion cannon that can be used later on as the foundation of a hybrid?

Sorry for the poor picture quality. Hmm, who could the last picture be for?

*The cannon was rebuilt after failure.
Attachments
Friend-o
Friend-o
Catastrophic failure: this is why you don't use Oxygen in a PVC gun.
Catastrophic failure: this is why you don't use Oxygen in a PVC gun.
With chamber open, fan on. &amp;quot;Why the hell did you put a fan with LEDs in your chamber?&amp;quot;<br />Answer- it was cheaper!
With chamber open, fan on. &quot;Why the hell did you put a fan with LEDs in your chamber?&quot;
Answer- it was cheaper!
Ignition
Ignition
Before the PVC MAPP bottle holder was added.
Before the PVC MAPP bottle holder was added.
Last edited by jrrdw on Sun Oct 20, 2013 2:19 pm, edited 1 time in total.
Reason: Fixed video.
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mark.f
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Thu Feb 14, 2013 11:44 am

If the cannon was rebuilt, why not post the rebuilt version too?

Your post in your pneumatic thread seems to indicate that you feel you "can't compete" with cannons like DYI, Larda, and Gippeto's.

Welcome to the club. :lol:

That's no reason not to post all of your work. I happen to think this cannon is really well built and would be interested in seeing a rebuilt version. Did you get the layout inspiration from Klugeboy's BFSG-4000?
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SweatNTeflon
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Thu Feb 14, 2013 1:20 pm

Nope. I'd never seen Klugeboy's work until just now on YouTube. Man, that guy likes heavy projectiles. The chamber fan(s) he uses are far superior to my Radio Shack Rave Fan. I have a fan stripped from an old nail gun I plan to use in a 3" chamber for aforementioned metal combustion launcher.

The picture of the exploded cannon is the old version (2 separate metered pipes for MAPP $ O2)- this version has gas bottles attached with clamps. Pretty ghetto. The other pics are all of the cannon post-rebuild. I know the chamber is a bit aggressive, but I love boom-boom.

****Another VERY Important Warning: Don't bring your cannon along with you on your honeymoon (unless your new bride suggests it- mine did not). Seriously, I did that a year ago. Not good.
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jackssmirkingrevenge
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Thu Feb 14, 2013 2:30 pm

Wow, glad you're ok.

So after that explicit warning, you still want to mess with oxygen?

Don't mess with oxygen.

Hybrids aren't as complex as you think. My first one was made out of rubbish: http://www.spudfiles.com/forums/mini-hy ... 21655.html
SweatNTeflon wrote:****Another VERY Important Warning: Don't bring your cannon along with you on your honeymoon (unless your new bride suggests it- mine did not). Seriously, I did that a year ago. Not good.
I have a better one ;) http://dontmarry.wordpress.com/
hectmarr wrote:You have to make many weapons, because this field is long and short life
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