tater guns

[DrEvil]

Are there any other tater gun owners here?

This is one I've had for a while. It had a cheap crappy grill igniter. One of those that only sparks once every time you push it. I got fed up with those so I upgraded it to use a spark gap igniter. After messing with it for over a month, I think it will finally work every time. It was shorting out through the moisture that accumulated inside after a couple shots.



Now it works even after about 10 shots.

[JohnYayas]

Are there any other tater gun owners here?

This is one I've had for a while. It had a cheap crappy grill igniter. One of those that only sparks once every time you push it. I got fed up with those so I upgraded it to use a spark gap igniter. After messing with it for over a month, I think it will finally work every time. It was shorting out through the moisture that accumulated inside after a couple shots.



Now it works even after about 10 shots.

What are you using for a propellant? Last time I messed with one was around 40 years ago. A friend of mine had one that his dad built for him. We were both around 8 yrs old I guess. Anyway, it Consisted of a bunch of soup cans duct taped together. The bottom didn't have a lid and the others had their lids and bottoms removed so that it could form a tube. We'd splash a cap full of gasoline in it, throw in a tennis ball and use a lighter to ignite it through a tiny hole that was drill at the very bottom. It worked really well and made a lot of noise.

Many years later, one of the guys I used to work with took one to the office so they could play with it in a field at lunch time. It had one of those gas grill sparkers on it. They were goofing off with it inside the building (very nice multistory office building used by several companies) and sparked it up and BOOOOOM it went. I wasn't around for it but I can imagine it freaked a few people out.

I've been wanting to build one but haven't gotten around to it. Do you know of a website for a good modern design? I don't think I want to go back to duct taped tin cans and gasoline.

[buffo]

Gary;

What you are describing is something we used to call a "polish cannon" back when we were kids. We used lighter fluid though, not gasoline. But otherwise it was the same thing - a bunch of drink cans taped together. They definitely weren't safe!

The original potato gun design was intended to run off cheap hairspray. But nowadays I've found that "static guard" is a much better fuel. It doesn't leave a sticky residue in the chamber, and it ignites very reliably.

As for how to build one, it's super easy. You need the following parts: (NOTE: Don't substitute! You want everything to be Schedule 40, not, I repeat, NOT DWV.)

4 ft section of 2" Sch 40 PVC pipe
9 inch section of 4" sch 40 PVC pipe
4" x 2" PVC reducing coupling
4" PVC threaded clean-out adapter
4" PVC threaded cap
Small can of PVC cement
Piezoelectric igniter

Drill a hole in the center of the threaded end cap and install the igniter. You may want to put some epoxy around the hole to seal it, but the threaded nut should be tight enough to keep it in place. (I sealed mine with epoxy though, just to be doubly-safe. Don't want any gas leaking out.)

Cut a 9 inch section of the 4" PVC pipe with a hacksaw. Glue the 4x2 reducer to one end, and the clean-out adapter to the other end.
Cut a 4 foot section of the 2" PVC pipe with a hacksaw. Glue it to the reducer.

Let everything dry overnight.

When you are ready to fire, shove a potato (or an apple) down the barrel just like an old muzzle-loading musket. The sharp edge of the pipe will trim off the excess and make a perfect potato "slug" that fits the barrel. Use a broomstick to push the potato slug all the way down to the reducer. (Don't push it too far or it will fall into the 4" combustion chamber.)

Spray some static guard into the 4" combustion chamber (one or two seconds should do it) and quickly screw on the end cap with the ignitor before the gas escapes.

Point the barrel in a safe direction and click the igniter. It will be LOUD! Also, there is considerable recoil, so be prepared for it.

A well made potato gun with a tight-fit between the barrel and the potato is capable of tossing a potato 300-500 yards. At close range it can shoot through a dog-eared fence board, so be careful!

The good thing is that they are very safe. The PVC is rated for 240 PSI, and normal pressures inside the chamber never exceed 40-50 PSI. So you don't need to worry about it exploding like a hand grenade. I have two of these things at home that are nearly 20 years old, and they still shoot just fine. (This is after hundreds of firings.)

Note, the pressure quoted above assumed that you're using static guard, butane, or hairspray as a fuel. If you get crazy and start using MAP gas or acetylene, all bets are off! (Personally I wouldn't recommend using any other fuel. Static guard works great.)

Adam

[Stuka]

Looks like an environmentally-friendly quad-killer to me...

[Bradfo69]

We used tennis ball cans and a soup can at the bottom since it was a little smaller in diameter. We weren't as bright with fuel though and used rubbing alcohol. Poured a tiny bit in a shook it around. I only ever fired tennis balls though.

Great... something else to bring to a SELEM. Why do I see a war in the field across the street with potato guns trying to take down quadcopters in about 2017? Lasers?? What lasers?

Of course, SELEM will be a 10 day 9 night excursion by that point.

[buffo]

Looks like an environmentally-friendly quad-killer to me

Bio-degradable ammo!

But yeah, a potato gun would totally destroy a quad, assuming you could hit one.

I once shot a golf-ball out of one of my potato guns more or less straight up. (Used some paper towels as a makeshift sabot.) The ball was in the air for over 30 seconds. (Do the math...) I have no doubt that if fired at a car's windshield, it would have gone straight through the safety glass. Scary!

Adam

PS: If you don't want to do the math, it works out to a muzzle velocity for the golf ball of roughly 330 mph!

[DrEvil]

What are you using for a propellant? Last time I messed with one was around 40 years ago. A friend of mine had one that his dad built for him. We were both around 8 yrs old I guess. Anyway, it Consisted of a bunch of soup cans duct taped together. The bottom didn't have a lid and the others had their lids and bottoms removed so that it could form a tube. We'd splash a cap full of gasoline in it, throw in a tennis ball and use a lighter to ignite it through a tiny hole that was drill at the very bottom. It worked really well and made a lot of noise.

Many years later, one of the guys I used to work with took one to the office so they could play with it in a field at lunch time. It had one of those gas grill sparkers on it. They were goofing off with it inside the building (very nice multistory office building used by several companies) and sparked it up and BOOOOOM it went. I wasn't around for it but I can imagine it freaked a few people out.

I've been wanting to build one but haven't gotten around to it. Do you know of a website for a good modern design? I don't think I want to go back to duct taped tin cans and gasoline.

I ran across this website while looking for some other fuels. http://www.spudfiles.com/

Fuels - http://www.aaroncake.net/spuds/boom.asp

I've been using static guard for mine. Somebody I was recently talking to mentioned starting fluid.

My barrel is 2" ID that is 30" long with a chamber that is 4" ID that is 22" long. I ran a long screw through the base on the barrel so the object doesn't get pushed too far down.

[Laser Wizardry]

" 15 characters"

[JohnYayas]

Geez, I had no idea they could have that much power. I remember the tennis balls from the one I played with going over the house but nothing like what you're all talking about.

[WookieBoy]

When I was a kid (15 or 16) I made one from some old cast iron piping I found lying around.
I drilled a hole for a spark plug and fitted a propane feed.

It was great fun. However the local Police Firearms officer confiscated it after a day or so of my playing with it in the fields out the back of my house.

He later told me he wasn't officially allowed to do so as technically it wasn't classed as a firearm... however, during testing at their range they managed to put a King Edward through both front doors of a Ford Fiesta at around 100 yards, hence he wasn't giving it me back.

He also said I was lucky it hadn't exploded in my face...