ABS tennis ball launcher with propane

Boom! The classic potato gun harnesses the combustion of flammable vapor.
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spudgunnerwryyyyy
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Here is my combustion. It has a 3" ABS chamber 24" long. The chamber has 1'' female threads to accept my 2 barrels. The spark is provided by a barbecue igniter. I am very satisfied by it as the whole thing only cost me ten us dollars for I reused an old igniter. This is my first combustion so please don't flame.

EDIT: I was going to use a 16 inch 4'' chamber but was out of the required fittings for a 4" chamber.

EDIT: I added a propane meter. Much more consistent firing.

EDIT: Added pistol grip and burst disc union sch 80. Also changed meter design. Very consistent firing. I am looking for a second hand 50mm fan.

EDIT: The pvc bushing is epoxied into the abs reducer so don't freak out.
Attachments
2.5'' and 1.5'' barrels both 48" long with 1'' threads to attach to chamber.
2.5'' and 1.5'' barrels both 48" long with 1'' threads to attach to chamber.
Tennis ball shot into towel used to stop it.
Tennis ball shot into towel used to stop it.
Detail of pistol grip and meter.
Detail of pistol grip and meter.
Over View of chamber, grip, and meter.
Over View of chamber, grip, and meter.
Last edited by spudgunnerwryyyyy on Tue Oct 09, 2007 10:44 pm, edited 6 times in total.
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In my experience with combustions i have found long chambers to be less effective than short stubby ones, something to do with the flame
front(s), this looks alright for a first attempt. What does the tape do around the back of the chamber near the cleanout cap?
Damage pics would be great. :violent3:
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spudgunnerwryyyyy
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Its Gorrila tape to insulate the screws from my hand :).
More comments would be nice. What should I do on design on my next gun. I mean besides fan and propane.
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Get larger size pipe for the chamber, you can have the capacity the same, and get a nice shaped reducer :P

Oh yeah and a fan, just use a ball valve and syringe for metered propane :twisted:
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spudgunnerwryyyyy
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Could you explain the syringe thing I haven't heard that method for metering propane.

edit now with propane injection.
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spudgunnerwryyyyy
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Added propane and burst disc for paint ball barrel. I am going to get a 20' long 1/2''barrels for double A's. Burst disc plus propane makes this way more powerful. Going to Fry's to see if they have 50mm fans for cheap.
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Sounds like it's coming along very nice :D
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f.c
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agreed it looks nice. makes me consider fixing up an old combustion gun i was given.
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spudgunnerwryyyyy
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Thanks guys. I updated pics and changed some designs. Worth checking out.
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spudgunnerwryyyyy
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I have done many tennis ball shots. I get about 11 seconds hang time. Video coming later.
shadowlanc17
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wow this gun is really cool haha good job for a first timer :wink: :wink: :lol:
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spudgunnerwryyyyy
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I love it, trigger is great, burst disc rocks. Tennis balls are so much fun. So loud.
mcoln1213
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that looks pretty cool
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noname
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Wow. Apparently, you have no idea how unsafe this gun is. You solvent welded a PVC bushing into an ABS reducer. THis gun is also handheld. Could you possibly be dumber?

Also, reducing the diameter to 1" in the middle decreases performance like hell. A burst disc is also useless in a combustion, performance wise.
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BigGrib
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Aside from the re engineering this needs ie noname's comment on the abs pvc no no, it looks like a good gun, i would re work the meter a little bit, she looks a wee bit cumbersome, maybe just clean her up a bit.
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