cannon

[kurt98]

I am building a cannon out of 2 inch diameter stock with a one inch bore. That gives me half inch thick walls. I am going to use gunpowder as my fuel. Is it possible that the cannon explodes and throws shrapnel every where? I know it could happen but how much gunpowder would it take to blow through half inch of steel.

[pastera]

Very possible that it will blow up.
The amount of power would depend on type and condition of the steel, the projectile size/mass, wadding, type of powder ... too many variables to safely give you an estimate.


Aaron

[steve323]

Ever notice that cannons are usually really thick near the base. There must be a reason. Be safe.

[Stepper Monkey]

Asking "how thick" is putting the cart before the horse. Thickness is only relevant once you know what the material and the calculated pressures are going to be.

As well, there is consistency. Last time we built a cannon we used forged, seamless, DOM pipe. Most tubing/piping is not going to be consistent due to seaming, internal stresses, heat treating, etc.
No matter how thick, you don't want something becoming embrittled and cracking or splitting on you.

This isn't a hard project to do at all if you just sit down and do the math, and know the alloy and construction method of your tube. Probably find cheap or free scrap that will do the task pretty easy.
If you don't know that math, learn it, find someone who does, or drop the project before you blow your ears loose.

[Fluxion]

I have been intested in small cannons my whole life. I have built a few display models and a few for firing with firecrackers and one carbide cannon. I want to build a black powder cannon. I understand the need for doing the math first and choosing the alloy for the barrel.

For my first black powder cannon I want it to have a 0.440" bore since I have quite a few pounds of 45 cal. lead balls on hand. Can anybody here help out with the math envolved? What alloys are good to use?

[Stepper Monkey]

For the small ones I just cheat and use unturned barrel blanks. The barrels set up for people making flintlock or percussion kits can be pretty thick-walled, leaving plenty of room to turn a cannon to scale proportion and leave plenty of meat. I have a .58 made from a 5-inch chunk of rifle barrel end cut.
The pressures are not that great with smaller bore models, leaving more leeway. Most scale proportions in brass will even work. The trouble comes in when you start trying to move balls way bigger than musket ammo!

[kurt98]

I shot my cannon today. I wrapped an round electrical fuse in paper for my projectile. It shot through a piece of ply wood 100 feet away.

[ImanCarrot]

I made a small cannon with a 1/2 inch bore... made all the chassis out of hand carved wood with little wheels and everything.

I used a ball of plasticine wrapped in paper and talcum powder as shot. I used a shotgun load of gunpowder (was VERY careful cutting up the shotgun shell).

I'd drilled a small hole at the thick end through which I poked a red hot bit of wire to set it off...

Well, the plasticine blew several holes in my living room wall (plastered brick) about 1cm deep with a spread of about 12" diameter as the cannon shot backwards about 9 feet into the other wall (my cat shot off in the other direction at a high rate of knots). The cannon chassis was wrecked and my ears were still ringing an hour later lol.

I consigned the project to my "to do" bin lol, good fun but take care hehe.

[riverrat]

NEVER USE TALCUM POWDER OR FLOUR IN LOADS OF ANY KIND!!!!!!
It compresses and swells in the bore causing an overpressure condition!
Be sure with black powder to use the right granulation, finer powders
like fffg are typically for .50 and smaller ffg is for .50 up to not sure
how big, "thats all I know from muzzleloaders" with cannons please
be careful guys you are throwing out a tremendous piece of lead.
A 1 inch projectile would probably go completely through a home or
a car.
my big ol .02 from growing up with firearms.

[kurt98]

I am thinking of making a 1 inch round steel projectile next. I want to see if i can blow a tree down. Where i will be shooting it there is 5000 feet of woods with no buildings.

[dsharp]

you may want to do some research on the greybeard site so you'll make it to 18.

[dsharp]

http://www.gbocannons.com/ Seriously, be careful what you are using for projectiles and types of powder. Powders produce a wide range of pressures.