easy safe crackling (stolen formula from China)

[spitfire]

To make a long story short...

 

just try it.

 

Copper oxide (black)..........68

MgAl 250 mesh..................30

Bismuth trioxide....................8

 

Mix, wet with nitrocellulose laquer untill it is a messy putty like substance. Let it dry until it can be crumbled.

Push trough a screen to granulate, let it dry.

Sieve the grains for different sizes/purposes.

Light one, get your brains pulled out of joy ; )

 

larger ones can be primed with standard BP (they light very easy)

smaler ones can be used in comets without any priming.

 

NO MORE TOXIC LEAD!!!

 

yay!

 

and.... why the F*** can't i post video's to my gallery???

[Mumbles]

First off, looks great.

 

Does this use 50:50 MgAl? I would assume so, but it's always better to be sure. There are a couple of formulas floating around allegedly from China in which they use alternate ratios. There is one particular DE formula I have in mind that is reported to work better with one of the others. Also, have you been using the most common 10% NC lacquer? DE can be sensitive to NC loading. The video looked like a pile of eggs. Do the granules go off in 1 explosion on their own, or do they fragment and kind of sizzle? Sorry for so many questions, but clearly my curiosity is piqued.

 

As far as the gallery, it's probably a dumb reason. We have to manually allow every file type. I'll check on MP4, but I would have assumed it was allowed. I'm at work, and will take care of it when I get home. Could be a size issue as well.

[spitfire]

i just used standard 50/50 MgAl. You can alter the delay of the crackling by using smaller or larger mesh MgAl. 250 mesh worked best for me now. Larger mesh MgAl gave poorer results. If very fine MgAl is used, they tend to fragment a bit. These don't, they go off at once. All of them. To my suprise, even very small grains give a very loud bang. It is however very critical to use high density Bismuth. It is a bit more expensive, but... you only need 8 grams to 100 grams of composition. So it's a cheap formula.

I used very syrup like NC laquer, i can't tell you exactly how much% it is. I just dissolve a spoon or three in acetone. I will write the ratio's down next time i make a batch.

 

When used in comets, make sure the comet composition is bound with water/dextrine or very little alcohol. Acetone or too much alcohol will dissolve the NC of the crackling grains and ruin them. I wasted two batches of comets this way... : (

[Ubehage]

Thank you!

 

I used to use 37.5 Bi2O3, 37.5 CuO, 25 MgAl.

 

This formula only worked with the bismuth I could get until 2014

Back then, my Bismuth looked like metal. And worked like a charm.

 

But, suddenly that was no longer available, and the only Bismuth I can get now looks like a dry yellow powder. And I have yet to find a formula that works...

 

I will try this one. Wish me luck

[mikeee]

To make a long story short...

 

just try it.

 

Copper oxide (black)..........68

MgAl 250 mesh..................30

Bismuth trioxide....................8

 

Mix, wet with nitrocellulose laquer untill it is a messy putty like substance. Let it dry until it can be crumbled.

Push trough a screen to granulate, let it dry.

Sieve the grains for different sizes/purposes.

Light one, get your brains pulled out of joy ; )

 

larger ones can be primed with standard BP (they light very easy)

smaler ones can be used in comets without any priming.

 

NO MORE TOXIC LEAD!!!

 

yay!

 

and.... why the F*** can't i post video's to my gallery???

 

Thank You!

[BlueComet24]

You said that these can be primed with BP, but I thought that KNO3 kills dragon eggs. Is this not the case here?

[Fulmen]

Nice video. Could you elaborate on exactly how much and the size/shape that was ignited?

 

Also, high density Bismuth? Can you be a little more specific?

[lloyd]

You said that these can be primed with BP, but I thought that KNO3 kills dragon eggs. Is this not the case here?

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

 

Blue, it's never been the case, either with lead or bismuth crackle. I've made thousands of pounds of it over the last 15 years (commercially). We always primed with rough-mix BP.

 

One thing that can kill crackle is deterioration of the Mg/Al. KNO3 mixed with water can attack the metal IF it stays wet too long. Quick drying is usually enough to prevent that, but sometimes we couldn't control weather and dry-room space.

 

So, to that end, we used potassium dichromate solution rather than plain water (in our commercial endeavor). However, Ned Gorski followed my formula exactly, except that he primed using water as the solvent, and was perfectly successful.

 

It's an old, well-respected war story that just isn't true, though oft repeated.

 

LLoyd

Edited February 22, 2016 by lloyd

[Zumber]

Thanks lloyd for elaborating it more....

[Ubehage]

One thing that can kill crackle is deterioration of the Mg/Al. KNO3 mixed with water can attack the metal IF it stays wet too long. Quick drying is usually enough to prevent that, but sometimes we couldn't control weather and dry-room space.

I have done a few tests of my own, and my experiences speaks against this

 

Sometime ago, someone quoted you in here in regards to how sensitive dried eggs are to getting wet.

I don't remember the exact quote, but it was something about DE not being very likely to get wetted with regular water - so I decided to make a few tests to gain my own experience:

 

I took some finished and dried eggs, and soaked 2 of them in a cup of water.

I also took 2 eggs and put on a sieve, just hanging outside.

And I did the same with primed eggs.

 

After about a week, all the prime was dissolved and the eggs were "clean". Other than that, nothing at all happened.

And after drying, all eggs worked perfectly.

[lloyd]

UBH,

The operative words are "can" and "IF". As you experienced, some water just does NOT attack the Mg/Al at all. Some (especially 'well') waters do.

 

We got away with both, but elected to use the dichromate solution in order to make absolutely sure it would not ever happen.

 

Umm... it sounds as if we're both arguing the same point -- that water is not so much the enemy of crackle as it's been made out to be! <G>

 

Lloyd

Edited February 23, 2016 by lloyd

[Ubehage]

Umm... it sounds as if we're both arguing the same point -- that water is not so much the enemy of crackle as it's been made out to be! <G>

 

Lloyd

I just re-read it all. We do agree

[spitfire]

Nice video. Could you elaborate on exactly how much and the size/shape that was ignited?

 

Also, high density Bismuth? Can you be a little more specific?

in the video you see a single 11mm comet, a standard Gold comet composition is used. Mixed with screened grains of crackling roughly 0.5 to 0.8 mm. I didn't weigh the amount of crackling used, roughly 20% of the total comet composition. Yes i used high density bismuth. LD didn't work. it just gave me some sort of strobe.

[Fulmen]

Thank you for the extra details, it really helps in the evaluation for such effects.

 

Still not sure about the HD vs LD Bismuth oxide, Ubehage describes a product that looks "like metal", is this what you used or the yellow oxide? As I understand it Bi2O3 is supposed to be yellow, so Ubehages product is somewhat confusing.

Or are we talking dense, ground powder vs fine and fluffy, perhaps precipitated?

 

I have some bismuth metal, so I figured I could make enough oxide for a batch or two...

[lloyd]

Fulmen,

All the Bi2O3 I've ever used has been a slightly greenish yellow, and a very fine powder which was fine-feeling to the touch, although pretty dense. It looked nothing like 'metal' to me.

 

We ordered it by the 5-gallon bucket-full from a US distributor in Pennsylvania. It was 100% US end-product, according to them, so I cannot speak to other countries' versions of the same material, except for the small amounts of Chinese material I've sampled -- which were the same color and texture.

 

LLoyd

[Fulmen]

Thanks, Lloyd.

 

Bismuth readily oxidizes in the molten state, but this oxide is dark grey. Only after heating this oxide to a dull red glow does it turn a greenish yellow like you describe. I'll try this first, if it doesn't work I'll melt it and grind it down, If that doesn't produce a dense powder I don't know what will.

[spitfire]

Thank you for the extra details, it really helps in the evaluation for such effects.

 

Still not sure about the HD vs LD Bismuth oxide, Ubehage describes a product that looks "like metal", is this what you used or the yellow oxide? As I understand it Bi2O3 is supposed to be yellow, so Ubehages product is somewhat confusing.

Or are we talking dense, ground powder vs fine and fluffy, perhaps precipitated?

 

I have some bismuth metal, so I figured I could make enough oxide for a batch or two...

This is an example of the problem i face many times. Different manufacturers/suppliers and their products. A formula that works for me might be trash when someone in the US or Australia tries it with chemicals from another supplier.

 

I used HD yellow Bismuth(III)oxide. A very fine dense powder. I had ordered LD once from the same supplier.... it was a disaster. The type i use now is from the electronics world. I have no idea what they use it for though, but it makes great crackling. I have never seen the oxide looking 'like metal' it looks more like sulfur, but very dense. 500g is just a tea cup in volume! The LD was 3 times more in volume, and lighter in color.

[Ubehage]

What I say it looked like metal, I only have my memory to support it

When I got the new batch, which is the LD and HD, I wondered about it. Because it was so different than the old batch, of which I still had about 100g to compare.

 

The old kind of Bi2O3 I had, looked like a bright-yellow version of MgAl. I never did any real comparisons or measures of particle-size.. Unfortunately.

 

That Bi2O3 was really easy to work with, and worked really good with 37.5:37.5:25.

And I still haven't made a successfull batch of eggs with the "new" kind

[zan89]

Yesterday i try formula, and it work perfect!

I use standard bismuth trioxide.

Eggs were from 0,5mm to 1,5mm

Edited February 26, 2016 by zan89

[Fulmen]

Does the 37.5:37.5:25 behave similar to the 68:30:8?

[Ubehage]

Does the 37.5:37.5:25 behave similar to the 68:30:8?

I have no idea..

 

When in powder-form, it would behave like crackling eggs; smoldering for a little while before going BANG.

When made into finished eggs, I could easily make 10mm-cubes with 70mesh MgAl. They would smolder for ~1.5 seconds and then explode with a LOUD bang. Almost like a gunshot.

 

With 150mesh MgAl, I could make very nice crackling that would explode in small potions with 1/10 seconds interval (there about) when made into 2mm thick strings.

These were AWESOME with some Titanium.

Edited February 26, 2016 by Ubehage

[pyrodoc]

Thanks for sharing, just need to order HD bismuth iii oxide now

[Fulmen]

I agree, this was inspiring.

 

Making BiO3 from shot seems to work fine, although it takes a while. While the metal quickly oxidizes when molten the oxide seems to passivate the surface somewhat. So I'm using a stirrer hotplate to agitate it, this disturbs the surface enough for the process to run at a decent rate. This oxide has a dark grey/black color, I assume it's BiO. It is then roasted at a cherry red temperature to convert it to Bi2O3.

 

The result is a dark greenish yellow powder with a bulk density of appr 4.5, it's probably contaminated with some tin oxide but I doubt if that is going to cause any problems.

[Seymour]

I've never tried the 68:30:8 but in my experience the 37.5:37.5:25 behaves just like the crackle Spitfire describes, with MgAl size being able to get everything from a cloud of small pops per grain, to pieces that pop several times, to bits that all go bang just once. With very big MgAl I have achieved pieces as large as one cubic centimetre going off in one very loud bang.

Normally though it is pieces about 1mm cubed going bang once. As has been mentioned, density is a factor, I think denser grains tending towards a single bang and less dense making multiple pops more likely.

 

I usually use NC to bind but have used other binders. I don't consider the binder to be as critical as some people think.

 

All my Bismuth trioxide has been a yellowish powder, from several sources.

 

While I have not tried it, I've read that tin oxide can work in crackle. I bought some and one day I should try it out.

Edited March 3, 2016 by Seymour

[Fulmen]

Interesting. I've only found one passing reference (http://www.pyrotubes.co.uk/apps/forums/topics/show/8637754), but it's worth a shot. That link also mentions antimony troxide, but as it's toxic I really don't see the benefit over bismuth.