SpudFiles

thebinderguy wrote:ok i'm going to try the masking tape burst disk. now if i can just find cam locks i'll be all set. i'm glad most of you agree the movie is a fake. i was starting to think i was losing it. Thanks a lot.

If you're inthe US, Tractor supply stocks them...

thebinderguy wrote:ok i'm going to try the masking tape burst disk. now if i can just find cam locks i'll be all set.

Northern Tool & Equipment in my area....look in the agricultural sprayer section... Tractor Supply also... McMaster Carr also has all models, poly and metal available.

this is a good design for a noise maker as long as your not shooting anything it is really loud so be careful where you are shooting it. it uses carbide to produce acetylene gas and that is what you ignite. normally this would be dangerous but since you are not sealing the chamber off it will be fine. You can get many shots off of one chip of carbide. Do not seal off the barrel leave it open. Put the carbide in first and then add the water. You can get carbide at hobby lobby for really cheap. btw i forgot to label the screws that is what you attach the leads of the wires to.

There is absolutely no need to go to so much effort! You don't even need to spend more than $10!
Over christmas we got a snack called cheese footballs, which came in a pringles-like tin, except it was wider (10cm diameter) and shorter (20cm). The bottom is steel and the cardboard is foil lined, and it has a pop-off lid, which is fairly tight. I ran a piece of cable through the cardboard as the spark gap (3mm spark).
At first i used propane. A few seconds burst, then put on the lid, and most importantly, wrap tape around the lid. This creates a burst-disk like effect, and it was good.
I soon ran out of propane and found a can of butane. WOW! a few layers of tape and it is deafening if pointed in your direction. The lid fires about 5m, and then you just repeat!
Cheese footballs: £3
Parcel Tape: £1
Power Cable: Found, but probably £1 a metre ( I used 10cm)
Stun Gun ignition:£20, but a piezo sparker is fine.

As with any combustion, the only problem is fuelling it consistently! I'm sure the cold weather makes it harder :'(

@spudtyrrant: I know you shouldnt use acetylene in a combustion but whyexactly is it so? It seems safe if made inside the cannon and in a well build metal combustion it should give some nice results, right?

Acetylene is very unstable and can be ignited therefore very easily by accident.

hey why don't you make a simple pneumatic burst disk device, if you don't mind pumping

Mmmm that's pretty simple too! I will have to try that tommorow.
I always find that pneumatics are quieter but of course far more reliable, choose your poison huh?
If you use a drinks bottle made for non-fizzy drinks, pump to around 100psi, then use a pin on a stick (I got away with just a stick), that is also VERY loud!

To pump mine up I jammed it onto the barrel of my 22mm ballvalve cannon, opened the valve and then just pumped it like normal. Don't forget your eye protection!

john bunsenburner wrote:@spudtyrrant: I know you shouldnt use acetylene in a combustion but whyexactly is it so? It seems safe if made inside the cannon and in a well build metal combustion it should give some nice results, right?

There have been a few carbide cannons, some made of old oxygen cylinders that fire bowling balls

You could also try somthing like my mini burst-disk noisemaker. It's just a reasonably sized pill bottle (the tape is to help hold my electrode setup nice and sturdy, and I put it on thick enough that if it did rupture it should contain the gas a bit. Obviously this woudn't work on a full size gun but I think it would help a bit on a mini.

Disregard the cone from the top of a drink bottle, this was merely to enable it to shoot flour and stuff into the air. On it's own this thing is very very loud (using 3 layers of alfoil as a burst disk). So loud that in an enclosed room it's a little uncomfortable even with earplugs in.

Pretty good considering it doesn't take any fancy parts and only takes a couple of minutes to make.

EDIT:

Forgot the picture

one more mundane question if you dont mind. how far apart do you put the screws when using a push button grill ignitor? thanks a bunch.

Only a few mm usually -the length of the spark, no longer!

thebinderguy wrote:one more mundane question if you dont mind. how far apart do you put the screws when using a push button grill ignitor? thanks a bunch.

Get them as close as you can without touching, 1 - 3 mm. I think that's what Biopro was trying to say.

Sorry Biopro, not putting words in your mouth. Just trying to figure out the angle on the answer you gave.

ok thanks,
i was using one of those lantern sparkers, but went with a smaller diameter on the pvc, so i cant fit it in there. so i'm using the grill lighter.
thanks again.

hello all,
i'm still trying to find camlocks for my noise cannon. no luck obviously or i wouldnt be writing. can you tell me what they are primarily used for. i dont really want to tell the salesman i'm building a cannon. he'll probably take down my license plate number or something. thanks.