Your misfires/duds/mistakes

[itwasntme]

I havn't seen a thread on this forum about failure and duds so I started one.

Last night I made some rockets using the teleflite propellent and primed with 3FG bp. When I went to launch them the first one lit and just stayed in the tube with very little thrust, that sucked.

The second one was a test using just KNO3 and sugar, no sulfur it didn't even light but I think it was the fuse not touching the BP. It sucked.

Post your stories!

[moonshot]

I rammed a rocket motor with some BP that worked good when I tested the motor so I thought I was good to go for production. I rammed 7 motors and built 7 rockets using the same powder.Spent a lot of time and effort making cut TT stars, making headers and bragging to my friends how these were great rockets and were gonna fly like eagles. Every one catoed and turned into star mines on a stick! DOH!

[Mardec]

At least you did get a starmine effect

 

Better than a cato with the rocket flying into the croud..

 

I don't have any misfires yet, I do have some rockets that went nuts but they were in their testing fase..

 

Once I did have a 2" that fell back to earth, but It had poor break so no one got hurt. Stars didn't get further than 2 meters or so

[unlisted]

Its not a rocket, but..

 

I had a 6" display shell misfire, the lift charge did not work properly; it only flew about 30 feet up.

 

The big problem was this was lit in my backyard, and was really close to a road. Thankfully, when the lift charge misfired, the shell did not ignite, so it was just a dud, falling to the ground. If not... I would be in a bit of trouble. Oh, and it was a professional shell to, I did not build it.

 

 

Than, another time, I was at a town shoot, and a new assistant loaded a 10" UPSIDE DOWN IN A TUBE!!! I am really glad that was a 100% electronic launch, they found chunks of the Mortar tube about 75 feet away.

[_Po_]

I once made a little (1 3/4") mine with some "white" stars that were a bit dodgey. None of them ignited and because they were so small (slow burn rate...when they do) the pressure built up fairly well. It made a loud bang and a few seconds later a few rooves were sprinkled, not very good.

 

Another time the fuse on a 3" shell didn't ignite (Thermalite fuse isn't too good at that unless the lift is right on it, which it wasn't). I got a video of it. You hear a bang, then me saying "shit, it didn't light...RUN!!!" and finally the sound of me running in random directions. Stupid thing to do, but pretty funny.

[Mumbles]

About the thermalite. This is assuming it is real thermalite, not imatation or some other brand, of which I cannot speak for. If you peel off the plastic ribbon wrappings, and 2 wires from opposite sides, it ignites like a champ. Never seen a failure. This is the method used by TheSidewinder from this forum, and perhaps Jim Freeman.

 

I'm a poor Mumbles, I just use blackmatch or split priming..

[_Po_]

It's the real stuff, wire core and wraps plus a plastic wrap. Pink box, 10 metres for $15. The shop I used to buy it from moved without notice and I only recently did a search to find it. It moved about an hour away. Where it was it was already a 3 hour drive from where I am now. I think I'll give them a ring to make sure they've got some, then buy about 50 metres because I'm down to about 4.

 

I've tried stripping the wrapping back, but when the lift powder isn't in direct contact with it (just poured in the mortar then the shell dropped down) it doesn't like working (I've done it about 3 times). If I get a little pouch of meal powder and attach it to the thermalite timer it's fine.

 

Making proper lift pouches and leaders would probably be better, but the mortars are so tight there isn't much room for a leader. Stupid HDPE sizes...

 

Blind used to prime his thermalite with a bit of BP slurry.

 

I guess I could make a lift pouch out of something like tissue paper, just sprinkle a bit of meal down the mortar and side fuse it. It'd ignite through the tissue paper. If I really wanted to I could probably just poke a hole in the tissue paper from the side hole. I'll sort something out, it's been a really long time since I've made/fired a shell.

[TheSidewinder]

Thanks, Mumbles. Yes, I use genuine Thermalite for cross-matching. (Jim Freeman uses it strictly for timing his crossettes, as far as I can recall.)

 

Po, are you breeech-firing these shells? If so, Thermalite probably isn't going to work as a passfire. It needs to be in intimate contact with your ignition source, as you've discovered. I top-fuse all my shells now. I tried breechfiring some 2" plastic cans, and for those I used that Chinese paper firecracker fuse (shown in the pics as an alternate method of passing fire to the timefuse) which I dipped in a NC/MP slurry. I never had a failure that way, although I admit I didn't fire many 2" shells. I switched to Thermalite and top-fusing at the same time, so I never tried what you've described but I can see it won't be reliable

 

I've *never* had Thermalite fail to take fire using this method for top-fusing:

 

 

From the pictures posted in my 3" can shell entry,

 

ZIP file of assembly pics

 

you can see how I prepare the Thermalite: strip ALL the plastic off, and 2 of the 5(?) wrapping wires. For the passfire to the time fuse, I wrap the ends of the Thermalite around the blackmatch leader, then run the lift-passfire down from the timefuse into the lift charge. I don't use Thermalite for passing fire to the lift charge (how would one DO that anyway?), I just cut the quickmatch passfire with 2 or so inches sticking out of the end, then fold one bottom flap down under the protruding blackmatch, pour in the lift charge, then fold over the rest of the outer wrap. A turn or two of twine right at the bottom of the shell keeps the lift charge where it should be.

 

INTERNALLY, I use a cannule pasted to the top disc, and pour the break charge inside the cannule. I've bent the ends of the Thermalite parallel to the timefuse. It's never failed to PASS fire to the break charge, either.

 

Hope that helps. I'm hoarding 3 rolls of Thermalite that someone was nice enough to sell to me.

 

M

[cplmac]

We were firing our annual show and someone made a major mistake. They loaded a 4" chain in a 5" rack. Wiped out an entire bank of our show. Luckily noone was hurt, that mistake has not been made since. All of our guns were set up in a large pit, so the blast was contained.

[Mumbles]

I worked on a show over the 4th. They were hand firing shells(I got stuck on cakes and the like)*. The bottom blew off the 6" steel gun causing a low break. The crowd ate it up, but the firers possibly shat themselves. After taking the tube out, there was a big almost mushroom cavity under it.

 

 

 

* - I got to fire a cannonade though, which was kick ass. Those things hammered. It went out halfway through though. There was a problem with the setup. They didn't let me relight it, someone else did though.

[psymon]

When I was learning how to make rockets I made a 10cm core burner rocket with 75/15/10 BP. Didn't realise I had to make the fuel a little less powerful. Lit it expecting a nice launch and a lovely tail. What did I get? The biggest BOOM I have ever heard. The garden was covered in confetti and unburnt black powder grains. Soon after I realised that 60-30-10 is a better fuel ratio...

[ActionTekJackson]

This last 4th JAP and I put on a show, and I only had two weeks to perfect my rockets for the show, and this was after a year of no pyrotechnic activity (thanks alot college). So as you can imagine I had quite a few failed tests. Have a look. Video "Picture 009" had a flash header on it, it's not actually a cato, the endplug blew prematurely igniting the header, had an awesome effect.

 

Picture 004.avi

Picture005.avi

Picture006.avi

Picture008.avi

Picture009.avi

 

*edit* Large video files, not for 56k users *edit*

[ewest]

This was from a while back but I made a 3/4" Stinger Missle and put a commercial festival ball as a heading. Well, it took off real wobbly and never really went anywhere. By the time I found it with the camera the festival ball blew up on the ground making a nice green star mine.

 

I've made maybe a dozen or so Stinger Missles but I can't really get them to do anything, they go up and fall right back down to the ground within a couple seconds. That's without a heading they do that, and yes I know they're spin stabilized so a heading effects them. No salute headings for these things...

 

But I'll keep working at it because they're cool looking.

 

3/4" Stinger Missle with Festival Ball heading

[Bug_X]

When I was learning how to make rockets I made a 10cm core burner rocket with 75/15/10 BP. Didn't realise I had to make the fuel a little less powerful. Lit it expecting a nice launch and a lovely tail. What did I get? The biggest BOOM I have ever heard. The garden was covered in confetti and unburnt black powder grains. Soon after I realised that 60-30-10 is a better fuel ratio...

I used the worng fuel in the beginning too. They where same VERY large CATO.

 

But I believed that it was to week tubes, I tryed 30 rocket before I understand that it was the fuel.

 

Now they fly very nice and I´m fairly good to roll tubes.

 

/ Bug

[moonshot]

Here is a vid of a 2" shell that went off in the tube. I was using a mix of home made BP and some 2fg to lift the shell. I obviously added too much 2fg! I guess this is why they call it pyroMANIA!

http://s107.photobucket.com/albums/m314/di...=Picture062.flv

[mormanman]

I thought that this was kind of funny in a stupid sort of way. It didn't happen to me, I heard Rich Creasy talking about it. A Pyro for the Texas Rangers.

A guy got a hold of a TEN INCH and was playing with it in his house and called his wife into the room and said, "Hey, look what I can do." He lit the fuse and put it out and then did it again only this time the fuse didn't go out. His house didn't blow up but the had to tear it down and start over.

That is a Failure on his part.

[flying fish]

Once I had a shell that failed to explode. I was worried until I found the shell, because I was afraid that my neighbors would run it over with the lawnmower which could probably cause a significant injury if it blew up. It was also a plastic shell, so it was too well sealed for the rain to destroy it. Anyway, after finding the shell I opened it up and discovered the problem: the fuse took fire just fine out of the mortar, but was crimped at the end going into the shell. So, I guess the sparks shot down out of the shell rather than going up into the shell and ignighting it.

 

That's two things that I have to remember not to do now - make sure the fuse is not crimped at the end, and also make sure I'm pointing it in a direction that will not cause it to land on anyone's lawn!

[Swede]

This is a fun thread. A while back, I had a CATO that makes me cringe thinking about it.

 

Like others, my fuel was too hot. It was only a 4 ounce rocket, but the noise was incredible. Here's what happened.

 

Motor + stick is in the launch tube. The header was some simple thing, but I obviously overcharged it. I'm in my suburban backyard, and have it pointed towards 6 acres of vacant lot nearby. The rocket went about two feet, and exploded powerfully. Oh No, where's the header? The worst was yet to come. About two seconds later, the header blasts on top of the neighbor's roof! I saw no stars, I think the whole thing blew blind from too much burst.

[Miech]

All my 3/4" test rockets produced last three weeks gave me a loud cato. I think my meal is just too good, because there was no core and the venturi was over 6 millimeter. A bigger venturi prevents a cato, but it also brings down the thrust way too much to be useful.

 

Some months ago I was shooting some shells with fellow pyro's, when a 2" purple with D1 pistil flowerpotted. It had been really nice if it had been a starmine, and still looked great, but it just wasn't what it was meant to be. I also had a dud shell, which I never found back. Luckily I used the same tagboard shells I always use, so it was very unlikely it would still be dangerous since it fell into a swamp.

[Gunzway]

About a week or so ago, I had a small mine with TT stars. I was just testing their performance in the air (I thought they were crappy due to insufficient ball milling). I put way to much lift and it made a huge bang and sent the stars high in the air. But it was a windy night and the wind blew the stars towards the houses not the beach/river. The stars landed in people's backyards. But I kindly the next day came over and told them what happened and if they see any possible damage I'll pay for it. (They got trampoline and a pool cover, that was my major concerns). Luckily they had no damage. Also my neighbors are cool about my tests, if something did get damaged and I didn't go over they probably start to get worried. This way they know I am responsible and I won't start a fire in their backyard and just not say anything.

 

Lesson Learnt: Try to avoid windy nights, put devices on an angle so there is a more definite chance that they will go the way you want too.

[Swede]

I don't consider myslf a coward, but I have yet to talk to the neighbors about my hobby. I really need to do it. I want to maintain peace, as there's nothing worse that a crappy neighbor. I don't want to be that guy. I've really curtailed noisy experiments in my backyard, and now try to get out of town, probably a smart thing to do.

[whitefox77]

I have two "oops"s to report. The first was a mine that used a KNO³/Al mix I came up with for stars. The stars had previously worked well in small shells, but when used in a mine, they didn't work at all. I'm not sure if they were blown blind, or simply disintegrated (I believe they disintegrated as they were not very hard). The mix was similar to the Shimizu Falls mix, but had the ratios tweaked to produce a faster burning star.

 

The second I'd like to bring up was a low break I ended up with at the last show I put on. The shell reached only about 1/2 the height it should have got to. This resulted when I fired off a home-made cylinder shell from a commercial paper & plastic mortar tube. I had reinforced the tube it's self with 3 layers of good cloth duct-tape (not the cheap plastic stuff), at the base of the tube where the main force of the lift is I added an additional 3 lays of tape (total of 6 layers), and then coated the inside with water-glass. The tube has stood up to several shoots, and shows no signs of weakening or unwinding from the inside. The problem turned out not to be the tube at all, but the plastic base. The circular portion of the base that was inside the tube actually broke free, and got embedded about 1/2 inch into the ground, and the rest of the base was broken into a dozed pieces and scattered around. From now on I think I'll stick to using the paper tubes with plastic bases for use with the 1.75" ball shells. Better yet I think I'll start replacing those plastic bases with wood plugs.