Mini Cannon fuse problem

[RTT]

Hi

I got this mini cannon from Ebay:

 

http://i.ebayimg.com/images/g/Q70AAOSwcu5USyRj/s-l500.jpg

 

I don't have access to Visco fuse in my country so I tried to make a fuse from cotton string and match powder,

as soon as the fuse reaches the cannon fuse hole, the fire is put out (Sorry for my bad English).

I've also made a fuse by cooking KNo3 and sugar in water and then soaked the cotton string, that also gave the same results as the match powder fuse.

am I doing something wrong here? can you guys recommend a solution?

Thanks,

RTT

Edited December 20, 2015 by RTT

[dynomike1]

Let me ask you this. Do i see 2 holes in the back of the barrel? What are you using for powder?

[RTT]

No, only one hole (the one that shows in the pic)

For powder I'm using Gun powder taken from a rifle bullet maybe that's the reason?

I think I can make black powder, I have KNo3, Charcoal and Sulfur

[dynomike1]

What is the dia. of the bore?

What is the wall thickness?

I wouldn't shoot smokeless powder in it.( Black powder only) unless otherwise specified.

Make you some Black match.

Make sure the primer hole is open. You should be able to blow air through it.

Do not stand behind it.

That's not really a cannon it's more of a mortar for indirect fire.

[lloyd]

If you're having trouble with the match extinguishing when it gets to the touch hole, it's for one of two reasons, or a combination of them:

 

1) the BP from which you're making your match is not very energetic, and can't continue burning under the cooling effect of the surrounding metal.

2) the single strand is fitting so closely to the hole walls that it exacerbates condition #1, even if the match is otherwise 'good'.

 

Make up some much thinner match, such that three strands will fit into the hole. Cut a piece about 5" long. Zig-zag fold one end into three strands, so that the folded end pieces are long enough to penetrate the chamber wall, with just a little more protruding inside and outside.

 

The three will 'quickmatch' through the hole, and the long remaining single strand (about 3-1/2" to 4" long) will become your "time fuse".

 

If that doesn't work, your BP is defective, or as mentioned above, your touch hole isn't drilled clear through into the chamber.

 

But you used a term I'm not clear on -- "match powder". Do you mean pulverized striking matches, like from a book of matches? Oh... I hope not! Black match must be made from black powder. I presume that KNO3 is still available in your realm...

 

Lloyd

Edited December 20, 2015 by lloyd

[felixthecat]

hi rtt,,modern rifle cartridges DO NOT contain gunpowder they use some form of smokeless powder either nitrocellulose or nitrocellulose/nitroglycerin based which are many times more potent than black powder and extremely unforgiving of ignorance and mistakes but even using black powder for your intended purpose will be fraught with danger since this item is manufactured as a novelty and you know nothing about the metal used to make the barrel or the stresses and shock loading pressures that it can withstand reliably without bursting sending metal shrapnel into anyone/anything nearby.if I remember correctly dagny recently posted some pics of a miniature cannon that he had constructed but this was machined from high grade steel by someone who knew what they were doing so I would suggest that if you are interested in this type of thing you should start reading the threads devoted to cannons and prepare for a steep learning curve

[RTT]

Thanks,

This is a very small cannon, it shoots 3mm steel balls

I cant remember the wall thickness..I think it's about 3-4 mm

 

By "Match powder" I meant safety matches heads grounded to fine powder, I Guess I'll have to make black powder for the cannon and fuse.

 

It's true that the fuse is exactly the diameter of the hole, and also the gun powder has a slow burning speed so I guess I'll have to change that as well.

This is a video of the prototype of this cannon:

 

https://www.youtube.com/watch?v=IxHW-QGMuZ4

Edited December 20, 2015 by RTT

[RTT]

Hi felixthecat,

I've gone thru some threads before getting the cannon,

The gun powder in from M16 rifle, I don't know the material the cannon is made of but it looks very sturdy and its pretty heavy so I think it's ok (hope so)

anyway for the 1st few shots I'll make the fuse longer and stand at a safety distance.

Thanks for you input

 

[lloyd]

RTT,

That's not "gunpowder", it's smokeless propellant, and totally unsuited to the use you have.

 

Generally, without a percussion cap's impetus igniting it, and in as small a load as you have, it'll just 'puff' the pellet out a few inches along with a large gout of flame. Smokeless requires extreme containment to act explosively, most especially in that small of a quantity.

 

You need to make some BP.

 

Lloyd

[dynomike1]

You have to watch these e-bay cannons, there are a lot of imitations out there that will hurt you. The wall thickness needs to be 1 caliber of the bore.

[lloyd]

Mike,

He said that the walls are 3-4mm thick. Since it shoots 3mm balls, that sounds like >1 caliber to me! <G>

 

In any case, smokeless rifle powder isn't going to work in that thing.

 

Lloyd

[RTT]

Thanks guys

The thickness is at least 3mm, take a look at this pic, the barrel hole is 3mm and the walls looks the same more or less

http://i1090.photobucket.com/albums/i371/zhoufuhua1981/11_zpsd1fd64d0.jpg

 

I guess I'll have to make some black powder.

I made a ball mill but it's so load I can't use it when the wife & kids are home

Edited December 21, 2015 by RTT

[Arthur]

IMO you should check that the fuse hole connects to the main bore. then you should try to get or make some very fine fuse powder and some charge powder a little coarser, say Passes 100 mesh and passes 40 mesh, both of these to be well made fast black powder. Lets face it 10 grammes of powder will do for several shots.

[dynomike1]

Yea that was just for future reference Lloyd.

[felixthecat]

hi all,upon revisiting this thread i now have a couple of comments and 1 question... firstly my apologies to dagbu ,secondly i had no idea of the scale of this toy and finally rtt i have to ask the question that if you have access to 556 rifle ammo then im assuming that your in the u.s so why cant you simply buy a can of bp from your local gunstore

[RTT]

Hi Arthur, I will take your advice about the mesh sizes thanks

felixthecat, I don't live in the us and bp is illegal in my country but I have a friend that serves in the army so he got me a few bullets from his M16 rifle

[MrB]

Hi Arthur, I will take your advice about the mesh sizes thanks

felixthecat, I don't live in the us and bp is illegal in my country but I have a friend that serves in the army so he got me a few bullets from his M16 rifle

Look at it from another perspective... Making BP is most definitely illegal where your at. But owning ammo for a gun is legal? Don't think so. Meaning your breaking the law, your friend who gave you the bullets do the same, and it's most likely a offense with higher penalties. Either way, you need BP to make this thing work, so, start over.

Save the smokeless stuff for when you decide to get in to pyro, and use it for NC lacquer.

B!

Edited December 22, 2015 by MrB

[Arthur]

Hide the NC in acetone solution say 2% NC in acetone in a bottle with a good seal. You can always recover it by evaporation! Or use it as NC lacquer. With the amount of BP you are actually going to need per shot (maybe a tenth of a gramme) I'd just make a couple of grammes carefully. Shoot anyone with your cannon and you are gone anyway, remember that a good shot could be lethal at 100m so my best advice is to be very careful with the cannon. In my country it would by just it's existence be an unlicenceable illegal firearm, and that's before you bother about powder or projectile.

[lloyd]

"....remember that a good shot could be lethal at 100m..."

---------------

Right! What complete BS! A 3mm projectile fired from a 10mm long barrel?!? RIGHT....

<snicker!>

 

Lloyd

[Arthur]

If a shot fired from this device injures someone including the operator -count the offences (in their country)

 

Enjoy it with due care.

[RTT]

Thanks for the great tips!

never thought about it this way. I'm a grown up with kids so safety is 1st priority to me

but after reading your comments I'll give it even more attention and wont look at it as a toy.

Thanks you all

[lloyd]

I didn't say it couldn't injure someone nearby, mostly likely if it struck any eye.

 

You wrote "... could be lethal at 100m". I'd lay small wagers that it would barely travel 100 meters, let alone do harm at that distance!

 

LLoyd

[MrB]

At around 500 feet per second, muzzle velocity a 4.5mm bb is able to pierce skin at 20 meters. Since a 3mm pellet would have less mass and decelerate even faster, your going to have to reach some crazy muzzle exit velocity for it to be lethal at 100 meters. Agree completely. But i think it's more of a warning along the lines "This is NOT a TOY! Do NOT aim at things, or people that you don't want to break, or hurt." but thats just my guess.

B!

[Arthur]

OK I may have the distances wrong. BUT the point still stands that if you puncture anyone with this then expect your country's "Men in Boots" to ask questions. Even if owning a small bore gun is legal shooting someone will likely be illegal, whatever your country of residence.

 

Maybe a good plan is to have a small "target range" with an adequate sand bag at the end.

Edited December 24, 2015 by Arthur