Page 2 of 3

Posted: Thu Jul 19, 2007 6:58 pm
by benstern
Just make a spring loaded harpoon. It would be just as easy and more fun due to the ability to reload underwater. I am gonna make a graphic showing how to build one.

EDIT: image

Image

Some spear guns use elastic bands. So just use latex tubing to launch something instead of a spring.

Posted: Thu Jul 19, 2007 9:48 pm
by homedepotpro
big-mac: im going with this ammo because of its weight and lack of too much friction/resistance

benstern: this is the gun, it is pneumatic. i looked into latex tubing gun idea and i thought this would be more fun to build and have more than one use.

Posted: Thu Jul 19, 2007 11:05 pm
by Big-mac
still you could use a small diameter steel rod...for strength and what not.

Posted: Thu Jul 19, 2007 11:18 pm
by homedepotpro
i actually did
Image
it is considerably heavier though, and shoots at lower velocities but with much more impact force

Posted: Thu Jul 19, 2007 11:23 pm
by paaiyan
I see you did decide to put a bit of a bevel on that tail there. What'd you use, epoxy?

Posted: Thu Jul 19, 2007 11:27 pm
by Big-mac
wouldnt it be better for under water. it could shoot farther. more weight u know

Posted: Thu Jul 19, 2007 11:29 pm
by homedepotpro
yeah i know it need more weight so i pick the rod up at home depot. oh the bevel is just hot glue, do you think it needs to be epoxy?

Posted: Thu Jul 19, 2007 11:34 pm
by Big-mac
how do you load it with the wire tethering it? ps this is cool i didnt mention before

Posted: Thu Jul 19, 2007 11:47 pm
by homedepotpro
unscrew the barrel and breach load it, the string is coiled in the breach and pulled out with the spear.

Posted: Fri Jul 20, 2007 10:55 am
by spud yeti
its a really cool idea, but how well does it actually work? You should shoot it under water and the air released would look like an uber fart :D

Posted: Fri Jul 20, 2007 11:02 am
by homedepotpro
spud yeti wrote:its a really cool idea, but how well does it actually work? You should shoot it under water and the air released would look like an uber fart :D
yeah, i know, but i did the math and there is only going to be like a liter and a half of air being released, so it shouldn't be too huge.

Posted: Fri Jul 20, 2007 11:16 am
by blue2583
good idea i think itll work. :lol: :lol: :lol: :lol: :lol:

Posted: Fri Jul 20, 2007 1:53 pm
by jackssmirkingrevenge
Pneumatic spearguns are nothing new, the physics has alread been covered :) Nice effort HDP, though may I suggest a larger chamber (as well as some deft use of the "crop" funtion of your chosen image editing program for the fourth pic :P )

Posted: Sat Aug 04, 2007 4:07 pm
by iknowmy3tables
could you please show me wher you put the schrader cause it looks like its in the center from this angle and that would be on the output side

I'm trying tomake a flexible chamber barrel portable gun

Posted: Sat Aug 04, 2007 4:29 pm
by ProfessorAmadeus
So say you take this under water to a consiterable depth like 30 feet. The air pressure will lose a fraction of its power and therefore need more air for the same amount of power it has at the surface. Now I am just guessing that this chamber will act the same as scuba equipment but I may be wrong.

Also if you are into scuba they make adapters that you can attach to your first stage regulator that is like a bike pump adapter for a compressor. I think they are only like 50 bucks. Then you can reload under water.