Why did my flash powder burn so slowly?

[DjGopher]

Hello!

So, I've been playing around with flash powders for a few years now. Nothing major—I'll just get bored once in a while and set something off.

Recently I decided to order a few extra chemicals to toy with. Among those were sulfur, and the not-so-popular copper nitrate (II).

 

Today I decided to follow Shimizu's Flash #11, which calls for 64% KClO4, 23% Al, 13% S.

Shimizo advertises this as being the loudest possible report for Al/KClO4/S mixtures.

In addition, I added about .27 grams of Cu(NO3)2 to the 20 gram mixture, hoping for some minor green lighting.

 

However, there was no bang. The cap (tin), which is typically broken into pieces from a normal 7:3 mix of perchlorate and aluminum, didn't even fracture. Instead it glowed a bright yellow-orange for several seconds.

 

Other info:

My aluminum is German Dark, and has never given me problems before.

The tin blasting cap was about 5 grams of comp away from being completely full. (not completely confined)

 

So my question is this: Why did it deflagrate so slowly? Was there really enough Copper Nitrate (~1.33%) to do anything? Was there too much sulfur or not enough perchlorate? (etc)

 

Thanks!

Dj

[LambentPyro]

You need a control to compare it with, did you perform it without the Copper Nitrate? Edited December 10, 2013 by LambentPyro

[psyco_1322]

A few things. You are not going to really get a colored flash with Al as the fuel. You are not going to get a green or blue flash by adding in copper nitrate. Copper nitrate really has no use in pyro, it's mostly in a blue pentahydrate form, meaning it has water in itself. You can get pounds of copper nitrate for a decent price as root killer, if you wanted to use it for other scientific experiments. You really should have tried some of the mix with out the nitrate in it, otherwise, there is not definite way to say if that's the source of the issue. Blasting caps are not a part of building fireworks. They are far from whatever "tin" container you are using filled with flash, that's a salute, with a shrapnel hazard. That being said, you really should not be making salutes with anything but a paper tube, take some responsibility, paper is safe, cheap, and eco friendly. When you add sulfur to a comp, it increases it's sensitivity to flame, friction, and impact, so keep that in mind. It's also not really going to make much of a difference in small devices, and in the end, it really just changes the tone of the report. When large amounts of comp are need, sulfur is usually added to cheapen up the mix, as it's relatively cheap and can be added with out affecting the performance.

 

Just a few things to inform you. You might not find the warmest welcome when you come on and say all you do is blow stuff up every once in awhile for fun. I'm not going to judge, but others might, so don't be surprised if you get some negative responses. You should really look into building some actual fireworks, you can still get your booms in while making nice pieces of art.

[Bilbobaker]

Flash fountains with differing metals and charcoal in layers are pretty nice.
Waterfalls are amazing.

[pyrojig]

 

The tin blasting cap was about 5 grams of comp away from being completely full. (not completely confined)

Clearly the intention is not one for pyro. It appears that the intent is one that belongs in the H.E. section . This being a first post approach with flash and talk of blasting caps is not going to find favor in the forum. It seems that the copper nitrate and the attempt to get a color , is only masking the real intent . Look , Im not bagging on you , and trust me exploding devices have a place in pyro. Blasting caps however do not. Many of us have started out the same way ( backwards) making boomers first and then fireworks . Most of us where just plain lucky to have all our digits .

Edited December 10, 2013 by pyrojig

[Niladmirari]

You should not use a copper salt!

 

3Cu(NO3)2 + 2Al = 3Cu + 2Al(NO3)3

And hydrolysis: Cu(NO3)2 + Н2О = HNO3 + ...

HNO3 + Al = Al(NO3)3 + ...

Composition may ignition!

 

Use metallic copper for flash.

[Mumbles]

Copper nitrate does not hydrolyze into nitric acid. Just because you can draw a reaction doesn't make it feasible.

 

Blue reports will require some trickery or exotic reagents. I suggest you take what others in this thread have said to heart.

[pyroman2498]

Hello!

So, I've been playing around with flash powders..........

However, there was no bang. The cap (tin), which is typically broken into pieces.......

 

 

 

Ummm well where do i start on this , Why in the world are you playing with FP ?? just adding copper nitrate to a mix isn't going to make it burn blue ......and than what really gets me , Why in the gods hell on earth are you using Tin for FP your just asking for shrapnel to pierce into you, and your calling it a cap like its a blasting cap, i think you should go back and read some more before you end up killing your self .. im not trying to be mean but really a tin cap and just messing with FP *Facepalm * no matter how much experience you say you have you should never just mess with flashpowder and putting it into a metal container is asking for unwanted experience.

You can get pounds of copper nitrate for a decent price as root killer,

Psyco, root killer is Copper sulfate, or at least all the root killer I've bought has always been 99.8% copper sulfate and it comes in 2# containers from lows . Thats also where i buy 100% lye and 31.54% HCl by the gallon , also other solvents such as toluene , xylene ,MEK,Etc its my own chem depot

[psyco_1322]

Psyco, root killer is Copper sulfate, or at least all the root killer I've bought has always been 99.8% copper sulfate and it comes in 2# containers from lows . Thats also where i buy 100% lye and 31.54% HCl by the gallon , also other solvents such as toluene , xylene ,MEK,Etc its my own chem depot

 

Shit, you are right, I was thinking of copper sulfate the entire time. Still, neither the nitrate or the sulfate really have a place in pyro.

[Novacastrian]

Hey pyroman what do you use the MEK for? Is it used the same as acetone?

 

I have access to a fair bit of the stuff.

[Maserface]

I have seen it used mostly to seal plastic hemis together

[pyroman2498]

Hey pyroman what do you use the MEK for? Is it used the same as acetone?

 

I have access to a fair bit of the stuff.

Well the purpose i use it for is for synthesizing luminol , well actually the hydrazine sulfate for the luminol by the hypochlorite ketazine process, the MEK is added to ammonia and than a exes of bleach is added , let to stand and let the layers form ,decant, and add sulfuric acid, than add to an ice bath to crash out the crystals , Thats the run down of that experiment (more can be read about it here). but its also a great solvent.

I have seen it used mostly to seal plastic hemis together

Im a green freak , i wont use plastic hemis , unless their biodegradable, but even than its still plastic and i prefer to use paper hemies

 

Shit, you are right, I was thinking of copper sulfate the entire time. Still, neither the nitrate or the sulfate really have a place in pyro.

well , you can react them with Sodium Bicarbonate to form copper carbonate , filter and wash it with copious amounts of water . and you should be able to use it in pyrotechnics. Haven't tried it though so i can only say from what others have done and not personal experience with using it in pyro .