I learned a fun New lesson yesterday on the 4th

[Uarbor]

I learned on the 4th of July that you need to test every new batch of everything. I made some fresh burst powder using willow for the first time. It was fantastic in my rocket headers. I decided to do a few srar mines to use up my leftover Stars using the same type of Mines that I had tested many times using my regular lift powder. Simple change of using willow instead burst all of my tubes. At least no one was injured but they were chain fused together so it was like slowly watching a disaster unfold. It was burst powder all right Edited July 5, 2021 by Uarbor

[pyroxision]

Ouch, glad no one was hurt!

[Uarbor]

Ouch, glad no one was hurt!

it was a close call but the spectators were just far enough away

[Arthur]

Decent tubes are usually bought from pyro suppliers. Sometimes industrial or commercial cling film is sold on robust tube cores. Then you need good plugs.

 

Distance is always your friend.

[Uarbor]

Decent tubes are usually bought from pyro suppliers. Sometimes industrial or commercial cling film is sold on robust tube cores. Then you need good plugs.

 

Distance is always your friend.

they were pyro tubes they were just budget oriented. And apparently not correct for the application. I have much better ones now

[SharkWhisperer]

they were pyro tubes they were just budget oriented. And apparently not correct for the application. I have much better ones now

What material were your mortars made of? Racked? What diameter mortars/shells were you firing and how much willow BP/tube? Or what % shell weight in BP? What happened to your shells? All flowerpots? Any launch? How high? Ground bursts?

 

You got video of that? Might be instructive for our more adventurous newbies.

 

Sheesh, Amigo, whenever you change anything at all, even the smallest detail like swapping in your willow BP, you gotta test that stuff safely before you do a performance for others.

 

Guessing that won't happen again. Glad nobody got hurt.

[Uarbor]

What material were your mortars made of? Racked? What diameter mortars/shells were you firing and how much willow BP/tube? Or what % shell weight in BP? What happened to your shells? All flowerpots? Any launch? How high? Ground bursts?

 

You got video of that? Might be instructive for our more adventurous newbies.

 

Sheesh, Amigo, whenever you change anything at all, even the smallest detail like swapping in your willow BP, you gotta test that stuff safely before you do a performance for others.

 

Guessing that won't happen again. Glad nobody got hurt.

the tubes were spiral wound three-quarter inch ID and 1 and 1/4 ID the 1 and 1/4 ID came with plastic bottoms. The 3/4 tubes I plugged with dowel rods and wood glue and drill holes into wood and glued them down into the holes. The three quarter inch tubes got five grams each which is what I was using before the 1 and 1/4 tubes 7 1/2 grams of Lift. On top of that I put an end plug with holes drilled in it and then a handful of stars and then plug the end with another end plug no glue. Fused at the bottom. The stars were Tiger Tail and Tiger Tail plus titanium. Everything launched Sky High unfortunately about a third of the tubes popped. The Spectators did not notice any difference but I was very worried as it unfolded. Spectators were about 50 yards away. And yes you can bet that won't happen again. I was really expecting the willow to be maybe 25% stronger or something it was more like four times as powerful. The Stars went like 50 feet high which is a lot higher than usual I always had trouble building up any pressure in the 1 and 1/4 tubes they usually only went 15 feet high or so. I wish I had video it was very spectacular. Fourth of July fireworks display that I've put on exists only in my memory now. I think I'm going to stick with Rockets. They all went off without a hitch my so-called star mines were just really Star Guns that I use to test my stars and I found out I enjoy them as much as any other fireworks Edited July 7, 2021 by Uarbor

[SharkWhisperer]

the tubes were spiral wound three-quarter inch ID and 1 and 1/4 ID the 1 and 1/4 ID came with plastic bottoms. The 3/4 tubes I plugged with dowel rods and wood glue and drill holes into wood and glued them down into the holes. The three quarter inch tubes got five grams each which is what I was using before the 1 and 1/4 tubes 7 1/2 grams of Lift. On top of that I put an end plug with holes drilled in it and then a handful of stars and then plug the end with another end plug no glue. Fused at the bottom. The stars were Tiger Tail and Tiger Tail plus titanium. Everything launched Sky High unfortunately about a third of the tubes popped. The Spectators did not notice any difference but I was very worried as it unfolded. Spectators were about 50 yards away. And yes you can bet that won't happen again. I was really expecting the willow to be maybe 25% stronger or something it was more like four times as powerful. The Stars went like 50 feet high which is a lot higher than usual I always had trouble building up any pressure in the 1 and 1/4 tubes they usually only went 15 feet high or so. I wish I had video it was very spectacular. Fourth of July fireworks display that I've put on exists only in my memory now. I think I'm going to stick with Rockets. They all went off without a hitch my so-called star mines were just really Star Guns that I use to test my stars and I found out I enjoy them as much as any other fireworks

Ahhhh, the cheapo Cannonfuse.com red/white/blue minimortars, it seems. Yup, have used those for starguns years ago. Blew the black plastic bottoms off of a couple before I upgraded my starguns. I think it was right around 3 g of willow lift that blew the bottom off of a 1.25" mortar after a few smaller ones. I would never have guessed they could tolerate 5g, and especially 7.5g, of hot lift. Would've warned you if I knew you were trying. Even with wooden plugs, those tubes just can't handle it.

 

"A handful" of stars. Yipes. Gotta weigh them or at least have the experience to eyeball in 10g increments. That's probably about 1.5-2 ounces of TT, which is a heavy load for those weak tubes. And a lotta lift if my estimate is right. I use 10% of the shell load in lift (hot willow; a little more if a wimpy BP batch you;re trying to get rid of) in minimines, and have never filled those cardboard jobs with more than an ounce of comp (that's what did one of mine in). Yup, you'll get nice launches to 50 feet, but the tubes won't survive many launches--that's about their max limit.

 

50 yards sounds pretty safe. Half that would probably have been safe if tubes were stabilized and unable to be knocked over, even if they were blowing their bases, but more is better in this case. Mines are a lot of fun, and the precursor to actual shells. I could just launch mines (and comets) alone all night and be smiling. And they're a great way to get rid of your less-than-stellar test batches of stars that don't really deserve a trip in a completed shell. Just upgrade your launch apparatus.

 

With safe tube, even just little 2", 2.5", and 3" mines are great for the back yard. Much more impressive than those little 1.25" cardboard jobs and safe if you use the right materials. Either HDPE or fiberglass, with solidly anchored wooden plugs. A lot of the cheapos have plugs just stapled in but screws, preferably two parallel ones going the same direction through the entire plug, are hardier. You don't want plugs blowing out on larger mortar/mine tubes and that can be a weak spot if not constructed properly. They're cheap to buy from mortar rack.com or countless other vendors (couple of bucks each already plugged). My current stargun is 4 sizes of iron tube welded onto a flat iron base, and BP would have a difficult time destroying those cannon barrels, but that's overkill for a basic stargun. Another option to replace your crummy ones is using 3/4" and 1" ID 1# and 3# thick-walled rocket tubes, plugged accordingly. Make no mistake, you can blow the sides out of those with a heavy charge, but they're much stronger than the comparatively thin-walled cheapo mortars with the black plastic bases that you glue on. Those things are better repurposed for insert tubes or fountains or salutes... just not really up to the job beyond small charges. If you plug your own mortars, you want the plugs "at least" as thick as your inner diameter of the tube. More is better, to a point. Much less is risky.

 

At least you know your BP is nice and hot! Remember your thread a few months ago when you were trying to dial in some slow-ass BP? Hah ha! Night and day, isn't it? Well, you got that sorted out; now a little attention to your starguns and mine-mortars' construction and you'll be back in the race! Just another reminder to take care in "testing" new items/loads for spectators--everything was the same as always, but really it wasn't... Don't dumb down your powder. Strengthen your launch materials.

 

Every step a learning experience. There's a lot of summertime left still.

[Arthur]

Learning points;

 

Distance is your friend

Test carefully starting at a big distance

measure and weigh carefully, overloading can be a problem.

 

However this time you got away with them so next time it's the same but better and more carefully made.