Loud foghorn from plumbing parts

This is a how to for building a loud foghorn from easy to get plumbing fittings and an inexpensive double acting air pump, the idea was to emulate the hand operated type used on small ships until the 1950's shown in pic 2.

Step 1: What you need

Here are the basic parts to make a noise

A hand operated pump, a sink waste trap and a rubber glove (for the diaphragm)

Comments

[Chief666]

Dear rog 8811,

I love your project and will start to build one soon. Just so I get my mind around what you are suggesting - the larger the diameter (of the horn section) the deeper the noise? If this is the case have you any comment on the max size that is achievable?

I was thinking of using an old fire extinguisher and cutting the bottom off.....

Thanks in advance

[rog8811]

Hi Chief, from experiments when building mine every time I lengthened the air path, by adding bits in, the pitch went lower.
The bigger the horn outlet the louder it became.

I hope that helps you with the design, good luck!

Regards rog8811

[IvanGorski]

Hey Rog, Great project! I want to make one, but where can I find a bottle trap like the one you used?

[rog8811]

Hi, I am UK based and found the trap in either a B&Q or Wickes store, sorry I cannot give you any more than that.
Good luck with finding the correct part.

[rog8811]

You could use pvc solvent adhesive, the sort used when joining plastic pipes.
I think I used quick setting 2 part epoxy...5 minute araldite.

[xnerdyxboyx]

How do you "stick" the 2 end parts back together?

[Bubbler]

This horn could be used to accompany the barking dog from next door. Or better still, use it when the barking dog's owner is trying to get some sleep. I like this one, and with a bit of echo added to the sound, we could be out on the calm icy seas off of Newfoundland.

[rog8811]

I mounted a motor in the end of the horn to rotate a baffle, a sort of leslie speaker cabinet type thing, it spun up a baffle to try for a reverb... I didn't have time to get it working as I was a day away from halloween and didn't have the time to play.....

I must try it again with a higher geared motor some time.

I am pleased that folk like this build.

Regards Rog8811

[halzark]

Awesome Possum!

[thejiggse]

Get some aluminum flashing, roll it into a cone shape, use aluminum hvac tape to retain the shape and then use the tape to secure it to the foghorn. By building four or five of these things with differing megaphone sizes your neighbors will quake with fear, as they think that they are hearing the aliens from War of the Worlds. How fun would it be to build about 20, and then set the neighborhood kids loose with them?

I think of Robert Duvall in Apocalypse Now, "I love the smell of napalm in the morning,..., it smells like victory!"

I say, "I love the sound of foghorns in the morning,...,it sounds like aliens have emerged from underground!"

[tanniynim]

I'm not following where we need to "drill a small hole in the back of this part so that it isn't fully sealed." Can you clarify this with another diagram or more information?

Also, is it necessary to "cut the bowl down to size by cutting a section out and sticking the 2 end parts back together?" Does this effect the sound if you don't?

[rog8811]

The hole is just a small one drilled somewhere in the screw on domed cover  to make sure that the volume behind the diapragm isn't sealed. The same part in fact that you asked about cutting.......
I do not know what difference not cutting this same part down in length will make, try it!
I shortened it as most fog horns have a very small volume of air space behind the diapragm.

Hope that helps.

Regards rog8811

[tanniynim]

I will try it before cutting! If we can save a step, lets do it!

[ynze]

Vuvuzela-horror! GREAT PROJECT!!!

Y.

[Kiteman]

You could add to the authenticity by adding a traffic cone.

Oh, and paint it.

[rog8811]

I did look at a traffic cone when I was gathering parts, the trouble with them I found was that they are very heavy and actually damp the sound a bit due to the thick wall. I doubt I will paint it as I like the fact it looks like what it is, a load of plumbing fittings connected to a pump :)

[Iridium7]

Just use one of those small cheap ones. Those should do fine.

[SHIFT!]

This is such a fantastic project! I love foghorns but I hate having to refill the compressed air canister- plus this is much more affordable and hand powered too!

This is going straight to my "Favorites"!

[bwells2]

Awesome!

[Cabe]

Did we learn nothing from the scourge of the Vuvuzela ? :)

[rimar2000]

Some years ago (maybe 20) I did a passive megaphone using a wasted central rotor from a cloth-washing machine. It was very effective, because its almost perfect horn shape.

[rog8811]

I remember my old mum had one like that many years ago, if I had come across one of those I would have given it a go, it would look good too!

[rimar2000]

Thanks for your response. I found one of these "horns" a week ago in the waste, and brings it at home. Anyway, they are cheap even new, as replacement.

Maybe I will post soon an instructable about that passive megaphone.