My Second Cannon - Now with a Safety :)

[webgeek]

This is my second cannon. Nothing exotic. I used 2" for the chamber to keep the price and parts availability nice and easy as 3" pressure rated fittings seem hard to find in my area. I extended the chamber right up to the sprinkler valve by putting a 2" to 1" reducer bushing right into the elbow. This seems to have noticeably increased performance over my first gun.

I also found an 1/4" NPT tap for 7 bucks which makes tapping into the sprinkler valve top trivial. Took less than 5 minutes from taking it apart to drilling and taping and reassembling it. I suggest tracking down the tap for anyone that plans on making more than a few of these. I HATE threading manually into the PVC or valve top. The threads are always a bit shallow and make me nervous (though I'm sure they are actually safe).

Shot video - my foot pump died on me so I only got two shots and only one had the potato hold up for more than a few feet out of the gun so I show that one.
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Here is a boring video of the gun itself - nothing special for you pros.
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In case you are bored and want a bit more detail on the gun, this is the video from my first gun - shows the breach a bit.
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Anyways, nothing special but I had fun with it. This week I'll make Mark III which will include a lot more features (pop off valve, gauge, better trigger mechanism, barrel support, etc).

Have fun!
--Mike

[MRR]

Nice build.

It's a good thing that you plan a barrel support on your next launcher, it reduces material stress points and increases accuracy.

[psycix]

Looks like a well-built launcher.
You might wanna shorten the hose though. And you might wanna screw that schrader valve through two layers of PVC, instead through the weak part: the cap.

For the rest: Great launcher!

[Mitchza89]

Very nice build mate. You can't beat simplicity. Keep up the good work.


You'll get the hunger all us spudders get for the all mighty piston valve soon though

[webgeek]

Thanks for all the nice comments and suggestions!

It's a good thing that you plan a barrel support on your next launcher, it reduces material stress points and increases accuracy.

Actually, the video doesn't show it, but gun #2 has barrel support now made out of some MDF and a large hose clamp that I created the a little after this original post.

You might wanna shorten the hose though

No argument, sadly, that hose is STIFF and any less caused it to kink at the sprinkler valve. I made the mistake of not using two 90 degree elbows in there. Next gun uses both a softer/more flexible hose and 90 degree connections.

And you might wanna screw that schrader valve through two layers of PVC, instead through the weak part: the cap.

Yup, that cap was already built before I got your suggestions on my other thread. All new guns use a threaded schrader through two walls. That's partly why I got the NPT tap - makes it nice and easy to make great threads.

You'll get the hunger all us spudders get for the all mighty piston valve soon though

I figure I've got a Mark III or Mark IV before I start doing piston valves. Next project after these is a t-shirt launcher

Thanks again everyone!

--Mike

[boom_o_matic_2.0]

very nice. so the ball valve is the breech? I didnt know the ID of the ball was the same as the ID of the pipe.

[Technician1002]

very nice. so the ball valve is the breech? I didnt know the ID of the ball was the same as the ID of the pipe.

Pardon me while I quit laughing...







Ok ok, Who cares what size the ID of a ball is? I'm only concerned the OD is smaller than the ID of the barrel..



Sorry couldn't resist..

[psycix]

Whats the laugh about?
If the hole through the ball of the ball valve was to small, you can't load projectiles in it which fit neatly into your bore.

[Technician1002]

Whats the laugh about?
If the hole through the ball of the ball valve was to small, you can't load projectiles in it which fit neatly into your bore.

In reading it, it looked like the ball was a projectile with a reference to the barrel ID. Oh.. Ball in the valve..

If you need a ball valve with full diameter, you may need to modify it slightly. The one I picked up to make a breech loader for a long 1 inch barrel is slightly smaller than the bore of the barrel. The 1 inch valve will load lemonhead candy, but won't load the 1 inch jawbreakers. Only about 1/2 the jawbreakers will fit in the barrel. I have to sort them.

[boom_o_matic_2.0]

Whats the laugh about?
If the hole through the ball of the ball valve was to small, you can't load projectiles in it which fit neatly into your bore.

In reading it, it looked like the ball was a projectile with a reference to the barrel ID. Oh.. Ball in the valve..

If you need a ball valve with full diameter, you may need to modify it slightly. The one I picked up to make a breech loader for a long 1 inch barrel is slightly smaller than the bore of the barrel. The 1 inch valve will load lemonhead candy, but won't load the 1 inch jawbreakers. Only about 1/2 the jawbreakers will fit in the barrel. I have to sort them.

lol yea I was talkin about the ball in the ball valve. lol. for some reason I always thought it was smaller than the ID of the pipe.

[Technician1002]

A quick note, sandpaper wrapped on a stick takes care of the small adjustment a PVC ball valve needs to match a barrel.