A new cannoner

[Cannon caster]

Hello. My name is Jugoslav and I am 14 years old. I am very interested in making small model cannons. Me and my friend made 6 cannons. I am also interested in metalcasting. You can see the cast brass cannon firing here: http://www.metacafe.com/watch/794729/firing_a_homemade_cannon_using_whistle_mix/ It is small but it is our first cast cannon. We casted it solid (the mold was a steel pipe close by pressed plaster at one end). Here you can see our furnace: http://www.metacafe.com/watch/744893/how_to_making_and_casting_brass/ Here is one of our stainless steel cannons: http://www.metacafe.com/watch/821548/firing_and_shooting_with_homemade_black_powder_cannon/ We made ths one by crimping the steel pipe at one end, heating it and striking it with a hammer to close it better, put a piece of lead in it and melted it in the cannon. When it soldified we drilled the hole or the fuse. So what do you think? We made our whistle mix and black powder ourself. Also has anyone here cast his own cannon? If yes can you please give me some advice about it? We casted our cannon solid and then drilled the bore but we can do it only with small cannons (we use a hand drill and dont have a large drill bit). I was thinking about using a steel pipe closed at one end (weld a plate or crimp) and use it as the core. The walls of the pipe would have to be thick enough to not to warp from the heat. Also is copper  (I have melted it many times and it is easy.) a god material to cast small model cannons from it? I know that it is soft but with enough wall thikness maybe it can work?
Sorry if it is too many questions.
Thanks in advance.
 

[GGaskill]

Check out this thread for a discussion of casting a half scale bronze mountain howitzer.

One thing you do not want to make cannons from is water pipe.  Most of it is rated at less than 1000 lbs/sq in which is too close to the actual pressures encountered in black powder cannons for safety.  Here in the US, we hear reports every year of some fool getting killed or seriously injured by an exploding "cannon" made from water pipe.

The practice of using a piece of pipe as a core for a cannon barrel is not held in high regard in many quarters.  Some people do it with more or less success.  You have to be willing to scrap a casting that is not perfect when using this process.  It is better to cast solid and drill the bore in a lathe.

If you can melt copper, then you should be able to make your own bronze; it just requires adding tin to the molten copper just before the copper starts to solidify, then mixing thoroughly and pouring.  Bronze is a much better material for cannon barrels than copper.

[Cat Whisperer]

Cannon Caster -

WELCOME to the board!

When I was your age I too made a few cannons from pipe and used my home-made black powder.  George is right, DON'T use water pipe.  I KNEW for YEARS that I'd never live to see 21.  Fortunately my blackpowder wasn't super good and I lived.

Having seen (from 15' away) a commercially built bronze cannon with a 1" bore (about 3" diameter at the breech) explode, I don't recommend anything other than using PROVEN designs that have been approved by such organizations as the N-SSA or AAA.  They've been in the role of hosting many shoots using many cannons from lots of folks and have come up with a set of guidelines for cannons that they'll allow in competition.

YOU NEED to KNOW that when you light the fuse it is a CANNON and NOT a BOMB!

These things don't fail a little at a time - they give NO warning, and failures are generally catestrophic.

So, DO YOUR RESEARCH.  Post questions here as to the design - lots of folks here with experience that will help.

LISTEN to folks here that express concerns - and address the concerns - that keeps y'all ALIVE.

There are a number of rules-of-thumb of design - read through the threads and you'll find them!

[Double D]

Dobro Jugoslav, glad to have a visitor from Croatia.  It's nice to hear from a young cannon maker  so far away.  Be sure and ask lots of questions  as there is a lot of experience here and all willing to help.

[Cannon caster]

The practice of using a piece of pipe as a core for a cannon barrel is not held in high regard in many quarters.  Some people do it with more or less success.  You have to be willing to scrap a casting that is not perfect when using this process.  It is better to cast solid and drill the bore in a lathe.

If you can melt copper, then you should be able to make your own bronze; it just requires adding tin to the molten copper just before the copper starts to solidify, then mixing thoroughly and pouring.  Bronze is a much better material for cannon barrels than copper.

Why is using a pipe core not a very good method? The only thing that can go wrong is that the pipe bends from the heat but using a thick walled pipe would solve that. Is there anything else that can go wrong? I don't have a lathe so I can't drill a large bore.

And about the bronze. Yes I can easily melt copper but I don't have any tin. Does anyone know where I can find it? But I do have a lot of zinc. I already cast a small brass canon. As far as I know brass is a good material for cannons. Is it? And about the copper. I know bronze is better but I would like to have a copper cannon. So could I cast a copper cannon 30 cm long, 13 mm bore diameter and wall thickness of around 1.5 cm to 2 cm? Or would copper be not strong enough?

You are right about those pipe cannons. They are dangerous. Around 1 year ago when I was much more stupid than now me and my friend made one from water pipe and loaded it with a mixture of potassium chlorate, sodium benzoate and charcoal. That is a very fast burning composition and the cannon blew up.

[GGaskill]

Is there anything else that can go wrong?

Besides bending or warping or other misalignment problems because you can't hold the inside end of the pipe in position, the pipe can partially melt and allow metal to flow into the bore of the pipe.  If this completely plugs the bore, it is not so bad as it is obvious and not much different from having to drill a solid casting.  If only small amounts get into the bore, they may be shot out as projectiles when one is not expecting projectiles. 

Not drilling or reaming the bore means you don't know for sure that the bore is round and of uniform diameter.  The pipe could have changed dimensions during the pour depending on how hot it got.

[Cannon caster]

Well steel should not melt if it is thick enough. I heat the brass to around 1000 C to 1100 C. Steel melts at more than 1300 C. I was thinking packing the tube tightly with sand to make it more resistant to warping. The pipe would be welded to a steel rod that would be embedded in a piece of wood that would be directly over the center of the cannon mold (steel pipe or lost foam mold). The pipe would be tightly closed by crimping it and welding over the place it was crimped.

And about the copper. I know bronze is better but I would like to have a copper cannon. So could I cast a copper cannon 30 cm long, 13 mm bore diameter and wall thickness of around 1.5 cm to 2 cm? Or would copper be not strong enough?

[rifleshooter2]

I really suggest the book " The More Complete Cannoneer " by M.C. Switlik It goes into the problems with casting around a steel tube. Alond with many other things. I wish I would have had it when I was starting out. It would have saved several grey hairs I have now from close calls when I was young.

Andy

[Cannon caster]

I really suggest the book " The More Complete Cannoneer " by M.C. Switlik.

Can that book be found on the internet?

And the steel pipe I am going to use as the core is 1.5mm thick. Made from inox (stainless steel). I have used pipes with only slightly larger wall thickness for pipe cannons. So they should survive the casting.

[GGaskill]

Can that book be found on the internet?

Not to my knowledge.  It appears that it is currently being updated for republishing anyway.

The 1.5 mm thick tubing you propose to use does not impress me for strength.  I would much rather see 4 mm thickness.  I would say you should do the math for stress calculations but you're a little young for that.  However, that doesn't mean that they don't apply. 

I suggest you visit Fundamentals: Types of Copper and Properties and take note of the tensile strengths of the various types of copper.  I would expect cast copper to be equivalent to the 060 Soft copper as it has had no mechanical working after being melted.  Copper is not a high strength material.

All that being said, as long as you keep the powder charge to a rational amount, you could do this.  However, your videos show the use of more powder than I think prudent.

[Cannon caster]

The 1.5 mm thick tubing you propose to use does not impress me for strength.  I would much rather see 4 mm thickness. 

All that being said, as long as you keep the powder charge to a rational amount, you could do this.  However, your videos show the use of more powder than I think prudent.

I will try to find a thicker pipe. I thought that the 1.5 mm pipe could be used because I have melted around 1.5 kg of brass in a can of slightly lesser wall thickness. You can see the can here: http://www.metacafe.com/watch/744893/how_to_making_and_casting_brass/ This time we melted much less than 1.5 kg of brass. The can held to around 10 melts before it failed.

And about the powder I used a lot because it is a slow burning powder. Using less than that wouldn't propell the ball very far and wouldn't be loud. We tried it in a shorter cannon and the ball flew only 30 cm. The powder only burned. I don't have a ball mill so I can't make a better powder.

[Cannon caster]

I suggest you visit Fundamentals: Types of Copper and Properties and take note of the tensile strengths of the various types of copper.  I would expect cast copper to be equivalent to the 060 Soft copper as it has had no mechanical working after being melted.  Copper is not a high strength material.

So cast copper would be equivalent to 060 soft copper. But what if I melt and cast some harder copper. Or would it change its properties when melted and cast?

[GGaskill]

It's the heat that makes it soft.  Unless you use an alloy (brass, bronze) versus pure copper, you will have the problem.  Heat will make hard copper soft.

It also makes brass soft; mechanical working such as rolling or hammering is what hardens copper alloys.

[Cannon caster]

Well then I will go with brass. Today me and my friend made 1.5 kg of 80:20 brass.

Does anyone know where tin can be found?

[GGaskill]

In the US, the psychotic fear of lead, in some quarters, has led to a ban on lead in solders used for joining copper pipe.  Those solders now are usually something like 95% tin, 5% silver.  I don't know what adding silver would do to a 90/10 copper/tin bronze but since the tin is only 10%, the silver (if added from a tin/silver solder) would be only about .5% and shouldn't have much effect. 

You'll have to check your hardware stores and see what the composition of the solders available are.  Since you won't be dealing with Home Despot over there, they may be of more help, so you should ask about tin directly, also.

[Cannon caster]

What is better for cannons brass or bronze?

[GGaskill]

They were made from both materials.  The last US ones were bronze.  In small bore guns, it probably doesn't make a lot of difference although bronze is generally a stronger material.

[Cannon caster]

Dobro Jugoslav, glad to have a visitor from Croatia. 

Are you also from Croatia?

[Double D]

Nope, but have been in the area. Spent a couple of months in 1993 working down in Skopje

[Cannon caster]

Could I cast a small brass cannon like this: place a cardboard tube in sand and use a steel pipe for the core? Here is a drawing:

[GGaskill]

Are you expecting the cardboard to burn away from the molten metal?

What are you holding the sand in?  Did you read the whole thread about casting the bronze howitzer?

[Cannon caster]

Are you expecting the cardboard to burn away from the molten metal?

What are you holding the sand in?  Did you read the whole thread about casting the bronze howitzer?

Yes I am expecting the cardboard to burn away from the molten metal.
The sand would be held in a metal can.
So would it work?

Yes I have read the thread. It was very interesting. It is not easy to cast such a large canon with sand casting. A very difficult to make pattern. I still hope that my easy way will work for a small brass cannon (around 30 cm long, 3cm diameter, 14 mm bore diameter).

[GGaskill]

Rather than using the cardboard, which would have to be fairly thick to withstand the ramming of the sand and would burn out irregularly, I would make the sand mould using a round metal bar for a pattern, ram the sand hard, then twist the bar and carefully pull it out.  Then insert your core.  I presume you are using a moulding sand (clean river sand with a little clay and water to make it all stick together) that will hold its shape after the pattern is removed.

[Cannon caster]

I was going to use ordinary silica sand. Perhaps a thick paper tube would then be better?

[GGaskill]

I guess it depends on what results you will accept.  The paper will not burn out uniformly so you will get an ugly surface, plus maybe you will have porosity problems with the metal from the gas being evolved by the burning cardboard.  Can you find some plaster and make a plaster mould?

[Artilleryman]

One of the advantages of casting is to cast a shape of the barrel including the trunnions.  It sounds like from the description above that the cardboard tube would produce just a cylinder. 

[Cannon caster]

Can you find some plaster and make a plaster mould?

Yes I have plaster and i tried to make a mold from it. I used a cardboard pipe with thin walls (1mm) and coated it with around 0.7-1 cm of plaster. Then when I heated the mould with a torch to dry it and burn away the pipe the plaster began to crack and when I took it fell apart. Then I tried it again but this time I immersed the pipe (with one end closed with duct tape) in a plastic bottle full of plaster. Then I also started to heat the mould to burn away the pipe but since the layer of plaster was very thick (around 2 cm, at some places perhaps more) The outside began to crumble while the inside wasnt even hot enough to charr the pipe.

Could I use the lost foam method?
Here is a link to the picture:
http://s209.photobucket.com/albums/bb248/Cigan_2007/?action=view&current=Lostfoamcannonmould.jpg

[GGaskill]

Your technique for the plaster mould is incorrect.  What you should do for a 3 cm diameter barrel is find a tin can about 15 cm in diameter and at least 5 cm longer than the barrel.  Suspend the pattern in the can, then mix and pour your plaster into the can.  Let the plaster set and remove the pattern.  Then weigh it on as sensitive a scale as you can find that will hold the weight.  Put the can into a oven at 100° C and let the plaster come up to temperature.  Every hour or so, take the mould and weigh it and record the weight; when the weight stops changing, you have driven all the moisture out.  Then raise the temperature to as hot as the oven goes (but no more than 500° C or the plaster will start breaking down, which is what is happening when you try to dry the mould with a torch.)  Melt your metal, get the mould and pour it.  Once the metal has solidified, remove the can and carefully break off the plaster.  Be careful if the mould has not completely cooled.

If you make a wax pattern with trunnions attached, you should melt the wax out using this process.  Be sure to start with a lower temperature to minimize the chance of setting the wax on fire.  Put a pan or can under the mould to catch the melted wax and remove it as soon as the wax stops dripping from the mould.  Also, be sure to run the temperature up to burn the remnants of the wax out of the plaster to prevent gas explosions when filling the mould with metal.

The second, high temperature heating in both cases cannot be ignored or you will be risking an explosion of liquid metal from gassified wax or water.  Not a fun experience.

[Cannon caster]

I would like to put the mold in the oven but I think my mom would not be very happy about that.

How about lost foam?
Here is the link to the picture: http://s209.photobucket.com/albums/bb248/Cigan_2007/?action=view&current=Lostfoamcannonmould.jpg

[kappullen]

cannon caster,

There's an old saying, "if you're going to do it, do it right" or something like that.

You are a young man, and very sure of your self.  Young people have little patience
and want it now!

A mistake with a cannon can have serious consequences in your
future, and that of innocent bystanders.

You need to heed the advise of those experienced on this board.

Your life, and that of others is in your hands.

You blow up a cannon and maim, or kill someone,
and we will all suffer from the government intrusion in the future.

There is a website with much information on casting, pattern making, and machining crafts here;

http://www.lindsaybks.com/

A cannon  properly designed, and fabricated, like the image you use in your posts, can be a thing
of beauty, to be proud of for the rest of your life.

Kap Pullen