marker gun project - epic fail!

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jackssmirkingrevenge
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Tue Jan 06, 2009 11:15 am

This section is for finished cannons, so this is appropriate :roll:

After this discussion a few months ago, I finally decided to make a prototype and it was looking pretty good, here are the parts before being epoxied together:

Image

I tried it out at 200 psi and it was working beautifully, so I thought I'd give it a go at 400 and well, it blew up. Mea culpa for not using a pressure rated marker!
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Recovered parts :-/
Recovered parts :-/
Detail of the muzzle bent out of shape after impacting with the wall at considerable velocity, luckily it wasn't pointing at me at the time!
Detail of the muzzle bent out of shape after impacting with the wall at considerable velocity, luckily it wasn't pointing at me at the time!
mgepicfail2.JPG (35.66 KiB) Viewed 5103 times
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jitup
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Tue Jan 06, 2009 11:21 am

too bad! It was such a cool idea. please try again!!!
if you live in Ohio join the Ohio Spud Gun and BBMG Association at http://www.ohiosga.webs.com
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jrrdw
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Tue Jan 06, 2009 11:25 am

What gave you the idea that a plastic marker pen tube could handle 400 psi? It is plastic, right? Looks like it. I'm just wondering. :shock:
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jackssmirkingrevenge
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Tue Jan 06, 2009 11:31 am

jrrdw wrote:What gave you the idea that a plastic marker pen tube could handle 400 psi? It is plastic, right? Looks like it. I'm just wondering. :shock:
Well, I figured the fact that it was syringe tube-epoxy layer-marker body it would be enough. In fact, interesting to note that it didn't explode outwards but the barrel flew out of the front, hence the broke section of marker. I'm thinking that if I had roughened the inside of the marker body it could have held.

I might give it another go, but if I do, metal body this time :roll:
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jitup
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Tue Jan 06, 2009 11:34 am

I would make like a metal "sleve" if you will, which contains the actual gun, yet is able to be placed in a marker forpure coolness factor.
if you live in Ohio join the Ohio Spud Gun and BBMG Association at http://www.ohiosga.webs.com
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jackssmirkingrevenge
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Tue Jan 06, 2009 11:41 am

jitup wrote:I would make like a metal "sleve" if you will, which contains the actual gun, yet is able to be placed in a marker forpure coolness factor.
That was the original plan, but the smallest practical tubing I had available was fractionally bigger than the marker interior so I went for this option.
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ALIHISGREAT
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Tue Jan 06, 2009 12:13 pm

jackssmirkingrevenge wrote:
jitup wrote:I would make like a metal "sleve" if you will, which contains the actual gun, yet is able to be placed in a marker forpure coolness factor.
That was the original plan, but the smallest practical tubing I had available was fractionally bigger than the marker interior so I went for this option.
safety first :roll: :wink:
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jackssmirkingrevenge
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Tue Jan 06, 2009 12:19 pm

ALIHISGREAT wrote:safety first :roll: :wink:
Health and Fu(king Safety :roll:

I'll admit it was a bit of a gamble, but given the tiny volume of air involved it wasn't that dangerous.
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psycix
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Tue Jan 06, 2009 3:42 pm

I'm thinking that if I had roughened the inside of the marker body it could have held.
What?!
YOU forgot to roughen up the inside before casting epoxy?

That was the original plan, but the smallest practical tubing I had available was fractionally bigger than the marker interior so I went for this option.
Well, besides looking for small diameter pipe, you could also have looked for metal markers or pens. Or maybe some other kind of tube-like stuff some examples: hull of a laser pen, mini flashlight or maybe a bullet casing. Basically anything thats metal, cylindrical, hollow and on the right size should do the job better then a syringe tube.

You can also reinforce the plugs by making small holes and put bolts (or on this size, needles) through the pipe wall. Maybe denting/bulging the metal inwards would also do it.
Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

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ALIHISGREAT
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Tue Jan 06, 2009 3:53 pm

jackssmirkingrevenge wrote:
ALIHISGREAT wrote:safety first :roll: :wink:
Health and Fu(king Safety :roll:

I'll admit it was a bit of a gamble, but given the tiny volume of air involved it wasn't that dangerous.
just make sure the next one works so i can have so damage picz! :D
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Sticky_Tape
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Tue Jan 06, 2009 4:55 pm

I guess I will have to try and show you up on this one! Nice gun bad fail.
You can tell how awesome a cannon is by the pressure used.
http://www.spudfiles.com/forums/high-pr ... 12803.html
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MrCrowley
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Tue Jan 06, 2009 5:03 pm

This doesn't look good on your record JSR :wink:
You're going to have a graveyard for all your failed prototypes soon enough :D

Though i'd give it another go, but using a metal tube for the chamber and sleeving it inside the marker. :)
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Sticky_Tape
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Tue Jan 06, 2009 6:00 pm

I would say screw the marker tube and just make it the size of a marker but this is pretty cool. just make sure you roughen the surfaces.
You can tell how awesome a cannon is by the pressure used.
http://www.spudfiles.com/forums/high-pr ... 12803.html
xnt rnm ne z ahtbg
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Gippeto
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Tue Jan 06, 2009 8:59 pm

This section is for finished cannons, so this is appropriate :roll:

Yup, she's done. :wink:

Have you considered a wrap or two of glass cloth around the chamber?

Perhaps cast some lugs into the ends through the tube wall to lessen the chance of their departure.
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VH_man
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Tue Jan 06, 2009 9:23 pm

Im currently doing this with one of those clicky sharpies..... Seems great minds think alike (hehe I can be full of myself every once and a while right!)

difference is I used brass tubing. I shall post it when I find a way to fill my gun with my shock pump........
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