Need advice: Building fireworks mortar/canon

[Oreo]

So I buy these 60gram 5" mortars for the holidays. They come with fiberglass mortar tubes. The trouble is I'd like to fire these mortars higher. I'd like to get them twice as high, if possible, but even 25-50% higher would be good. I'm thinking this might be possible by using a longer tube and maybe a larger powder charge. Obviously, I'm limited by the delay fuse length, but I'm willing to bet there's still plenty of room for optimizing the launch.

I'm thinking of buying some super-heavy gauge steel tubing, say, 1" thick walls, and double or tripple the length of the original fiberglass tube. Same bore diameter, which is pretty loose. I figure on tack-welding a steel plate as the bottom of the tube. I'd rather the welds break than the tube explode.

But, I might be way off base on all this. Please guide me to success.

[Alasgun]

“Success” would be leaving well enough alone!!

[Winger Ed.]

It's not so much the length of the tube that determines how high the shell goes up.
It's the lifting charge in the firework itself.

You can play around adding to the lifting charge, but the shell is designed for what it comes with.
Just adding to the lifting charge will probably shatter the container that holds the rest of the shell together.
If that happens, it'll probably burst as it comes out the tube.

Like the difference in a couple of inches of barrel length is related to a bullet's velocity-
you might gain a little with a longer tube, but not much.

[super6]

HDPE pipe is what you need, Glue and screw a 3'' wood block in the bottom. Build a rack to stabilize, Go with a 3' length and shoot to 500'. I use 3/8 wall tubing. And use a peace of chicken fuse!

[Oreo]

That's an interesting idea, Super6. I especially like the idea of a wood bottom plug, for safety. You think HDPE pipe is strong enough? What kind of lifting charge do you use?

Winger Ed, you're probably right about the firework canister having a design limit. I'm betting there's some room to play with though. I mean to experiment with fail-safes in place.

[Hannibal]

This thread reminds me of a saying I first heard a very long time ago.

'There are old mushroom hunters and there are bold mushroom hunters. But there are no old, bold mushroom hunters.'

[GregLaROCHE]

Thé size pipe you’re talking about sounds like a canon. Load it with BP and toilet paper and let it rip! It’s only going to make a Big Bang, but that’s what a lot of the fun is about.

[Winger Ed.]

I'm betting there's some room to play with though. I mean to experiment with fail-safes in place.

Don't shoot your eye out kid!:bigsmyl2:

[Sasquatch-1]

It seems to me that the timing for the burst is set so the shell explodes as it reaches a certain height. Any change in the lift really wouldn't be realized due to the shell exploding while still rising. You may get a couple feet at most.

[Nobade]

It seems to me that the timing for the burst is set so the shell explodes as it reaches a certain height. Any change in the lift really wouldn't be realized due to the shell exploding while still rising. You may get a couple feet at most.

My thoughts exactly. No way to lengthen the delay.

[Kosh75287]

What are you using for a lifting charge, right now? Is it likely that it burns faster than Fg grain gunpowder? IF it burns faster than Fg, then adding length to the "tube" (therefore increasing combustion time) may not gain you much altitude. IF Fg burns more slowly than your current lifting charge, then using Fg in a longer "tube" MAY give you higher velocities (therefore altitudes), in much the same way that longer-barreled firearms tend to exhibit higher velocities than shorter-barreled firearms (all other factors being equal).
Not seeing what equipment you are working with, it all sounds rather unduly dangerous. Then again, sometimes valuable knowledge comes from "for Spits & Giggles" experimentation.

[super6]

That's an interesting idea, Super6. I especially like the idea of a wood bottom plug, for safety. You think HDPE pipe is strong enough? What kind of lifting charge do you use?

Winger Ed, you're probably right about the firework canister having a design limit. I'm betting there's some room to play with though. I mean to experiment with fail-safes in place.


If you are using ball shells, HDPE is plenty strong enough, Cylinder shells not so much, May be two break at most otherwise use steel pipes and bury them. You did not say if you are planning to build your shells? If so time fuse or a spoolet will solve the time issue. Heavier granulation's of black powder will smooth out the pressure spike.

[Oreo]

They are 5" & 6" long cylinder shells that I buy. I don't make my own, but I was figuring on cutting the lift charge open to repackage a larger charge. I hadn't really settled on how to handle that yet, actually. I have no idea what the manufacturer used in there, but I guess I'll have to find out.

The timing of the shell is a simple burning fuse. It doesn't care what altitude it's at. My goal is to get a higher muzzle velocity so the shell reaches a higher altitude before the delay fuse is exhausted.

I'm using ones like these:
302417

[17nut]

https://www.youtube.com/watch?v=Txq3NM35_C4

[super6]

^^^ this So.. Your talking about 2-3" shells ? No need for the steel.

[Gtek]

Hey, hold my beer and watch this can have many outcomes. In my circle there is a shed the entire side was replaced due to a "failed launch", it appears tighter and longer did not equate to velocity and height in this instance. There was red, blue and gold things blazing between us, through our legs and by our heads and unbelievably not one burn. But boy howdy, not no but Hell no never again. My suggestion would be spend a little more for the ones that do what you want. I know, where is the fun in that, hey, hold my beer!

[jmorris]

You could go extra dangerous and make a sabot for your tube and shoot the whole thing up in the air before it goes off.


https://www.youtube.com/watch?v=X9sPuZkwiJY

[jmorris]

Saw dust and a road flare makes a pretty huge mushroom fireball, I made a “trigger” so I could be hundreds of feet away though.


https://www.youtube.com/watch?v=RMDGNdHERLE

[elmacgyver0]

Fireworks were recently legalized in Iowa; I am more than satisfied with what I can buy at the local stands.
Being in my 70s it is a bit too little too late, but I still enjoy them, my wife says I have the mind of a 12-year-old.
The local authorities, being a bunch of *******s reduced the time we can shoot them off to July 3rd & 4th and only 5pm to 10pm.
I mean ***! the Fourth only comes around once a year! All the liberal little old ladies complain they can't sleep, more likely they like to make people miserable.
Anyway, I hope you are not one of these guys on U-Tube firing bottle rockets from their butt crack, not a pretty picture, but I still laughed like hell.
I wonder what the ER people thought?

[Jeff Michel]

Might want to check with the local federals, laws varies from state to state. A good friend of mine who made fireworks of real quality, professional grade stuff. Used to go to firework "shows" where you could acquire your supplies and most importantly learn how to make fireworks. After 30 years of making fireworks, he had a test mortar get away from him and put a star into his 125 x 100 pole barn, chocked full of commercial made fireworks and stuff he made and stored (For people that don't have a license, current law states you can make fireworks, but it can't leave the property and it has to be displayed the day it was made) This got him into trouble later. The resulting explosion and fire completely destroyed his barn and a good deal of farm equipment stored therein. The ATF tried to charge him with domestic terrorism, he was 70 at the time. He ended up beating all the charges but it took two years and a wheelbarrow of cash.
Were me, I think I would be happy with what you can purchase. Just my opinion.

[georgerkahn]

Fireworks were recently legalized in Iowa; I am more than satisfied with what I can buy at the local stands.
Being in my 70s it is a bit too little too late, but I still enjoy them, my wife says I have the mind of a 12-year-old.
The local authorities, being a bunch of *******s reduced the time we can shoot them off to July 3rd & 4th and only 5pm to 10pm.
I mean ***! the Fourth only comes around once a year! All the liberal little old ladies complain they can't sleep, more likely they like to make people miserable.
Anyway, I hope you are not one of these guys on U-Tube firing bottle rockets from their butt crack, not a pretty picture, but I still laughed like hell.
I wonder what the ER people thought?

You need to read about Pablo Ruiz -- who placed a mortar upon the top of his head, set it off, and did not live to tell others about it :) -- https://nypost.com/2022/07/07/texas-pablo-ruiz-killed-by-firework-that-exploded-on-head/

302521

[725]

IMO, trying to reengineer some commercial fireworks is asking for trouble. Trouble from the law (unknown to me if even there are such laws but it would be my luck), trouble from the ER Doc who just shake his head at your resulting dilemma, and that never ending trouble from the wife who will certainly say she told you so. YMMV. Good luck

[Oreo]

I understand the dangers here, but guys, what I'm doing is just making a black powder cannon. That it's a firework is, or should be irrelevant. Like any black powder firearm, it needs to not explode, primarily. After that, whether it launches a golf ball, or a firework, or a blast of sparks... it will be in a safe location pointed in a safe direction, etc. etc.

The question is how to get more range (muzzle velocity) out of a muzzle loader? I hear the add more powder. I wonder how much more powder would help before I'm just blowing it out the end of the very short barrel? But I don't know black powder very well. I'm used to smokeless powder reloading, and I only know that things are a bit different with black powder. That's where I need the education.

[Winger Ed.]

Over on the 'Graybeard's Outdoors' site, there is a section just for BP cannons and mortars.

It might be worth checking out.

[BLAHUT]

i know a guy and his kid launching 16 lb bowling balls using black powder> 1/2 lb powder per launch ??

[W.R.Buchanan]

So I buy these 60gram 5" mortars for the holidays. They come with fiberglass mortar tubes. The trouble is I'd like to fire these mortars higher. I'd like to get them twice as high, if possible, but even 25-50% higher would be good. I'm thinking this might be possible by using a longer tube and maybe a larger powder charge. Obviously, I'm limited by the delay fuse length, but I'm willing to bet there's still plenty of room for optimizing the launch.

I'm thinking of buying some super-heavy gauge steel tubing, say, 1" thick walls, and double or tripple the length of the original fiberglass tube. Same bore diameter, which is pretty loose. I figure on tack-welding a steel plate as the bottom of the tube. I'd rather the welds break than the tube explode.

But, I might be way off base on all this. Please guide me to success.

I'd say you are just a little too far on the safe side for this application. Most of the Fireworks Mortars I've seen were made from Sonotube (Rolled Paper Cement Forms)

I have a friend who made a Bowling Ball Mortar from 8" ID Cro Moly tubing with a 1" wall thickness. When they proofed it with 1 lb of Black Powder is shot a 16 lb bowling ball 1 1/8 miles! This gun is so strong it could swallow a pound of Bullseye no sweat. It typically shoots a bowling ball 1000 feet strait up with only 3 oz of black. See pictures below. This thing takes four grown men to move!

You could definitely go with some 5-6" heavy mailing tubes or Sonotube for your barrel. For Sonotube go to you local Home Improvement Center and look around.

Randy

[Rapier]

If it were a solid ball it would be just increasing altitude, but the payload charge has a delay fuse which will still detonate at X seconds regardless of altitude. It is all timed, launch propellent fires, lights the charge’s fuse, etc. You do not want that charge to go off at head level, it contains neat things like magnesium and phosphorous, to make those pretty little sparkles that burn for a long time, could seem like a lifetime.
Suggest you leave it like it comes in the package.

[17nut]

Main problem is that the main shell is paper mache and has a finite structual threshold.
Accelerate it to hard and it will collapse in the tube :-(

Many years ago i made a mortar for shooting beer cans.
18-20grams~275-310grains of BP under a concrete filled beer can.
It went out of sight at the peak and out of 10 shots i recovered 2, the rest did a mole and disappered down (more than 2 feet).
Point is: At some point i tried to launch filled cans with a light load and all i got was wet as the cans collapsed at the end of the barrel.

[Oreo]

The structural integrity of the projectile is definitely something I have to give consideration to. I can probably make some inert for testing by removing the guts, and replacing with equal weight of sand, or something. I can test till I understand the limits of the canister.

[17nut]

Sand and BP arent the same, try damp soil, might be closer.
It's not the actual weight but rather the shift in displacement that's the main problem.