So I am going to be a senior in high school this year and I have already have a idea for a good prank. I have most of the supplies for this setup and I think nobody has every done it before. I am thinking of a backpack setup consistent of my paintball co2 air tank I have fit for compressed air and a solenoid valve which is key for this setup to keep me from getting busted. I plan on honking in the hall after class and act like someone else did it. Tell me what you think about this. ps i have 3 sets of horns I have one nathan airchime p5 only the p5, and 2 sets of dump truck horns I think the dump truck horns are what I will use due to size it has to look like a bookpack.
Hehe… another Hornblasters in the making.
Good plan, although I don’t believe your idea is unique. There’s been quite a few CO2 contraptions discussed here. If you do a search for the Deaf Leopard you’ll find some college pranks along similar lines. The P5 on CO2 will encounter airflow issues but would be fine for short bursts… just a lot to lug around though.
In any case, good clean fun - keep us posted on the event and outcome (video preferred) 
Just What this site needed, another Lunatic, welcome to the Asylum!:D:D
We wanna see the video!
I played with it as a manual valve it work but I like the auto setup better here is a link to my first try at this. http://youtu.be/WFpBs4NBsSg This horns were given to me for free so I need to find a use for them and I did.
I went back to the manual valve you just cant beat a manual valve. Batteries were the main reason for this change a drill battery would work best but I like how simply the manual valve makes things. I plan on taking this setup to my schools football games for touchdowns and honk in the stands. Does anyone know how to seal the backplates on these horns I have a lot of air leaking out the sides of the back of these sets of horns. They had alot of water in the horns and the air tank did to which caused the solenoid to stick but I did a full repair to that so all good.
Here are photos of both the train and truck horns. I like the truck horn the best for its size and sound. http://s1275.photobucket.com/user/glowingspy/library/
Ah I get you now… you have one bell of a P5. That’ll work
I thought initially you had the whole P5 running on gas.
I cant stop thinking of ideas to use this setup like going in to walmart and black friday. I am now using it as horn for my bike.
Believe me, you will soon want to upgrade, very soon. 
Thats a bike and a half looks like a work out to ride. I put a harbor freight megaphone on my bike that I have installed a input jack for muisc. Today i have found a new way of using paintball air tanks for compressed air. You take the valve that come with the co2 tank (it is red lock tight on there) the valve should be 3/8 in big but not tapered like npt so I cut the valve steam off of the air tank valve and screw that in to the air tank. Next you take a 3/8 female to a 1/4 npt male or female fiting screw that on to the steam of the valve that is now screwed in to the air tank. just saying if anyone wants to know.
Nice! You should get a vid of it. Yep, it is one hell of a work out to ride, the most heavy items are the York 210 and the car battery. Doesn’t help at all once I switch on the Alternator and the York, I save that for down hill.
Here is what I use on my bike now. http://www.youtube.com/watch?v=m5jMj4tGUZo&feature=youtu.be I love to use co2 tanks they are strong and light just in case I fall. Do the Cadillac horns real sound like a train?
Sweet!
Well they sound like this http://www.youtube.com/watch?v=1pSQQ-uSoTI
Pretty Impressive for an electric horn, no air tank needed and you can fine tune them to go louder.
I am going to try to make a bike powered air compressor using a york compressor kinda like you but just stationary bike.