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Improved Hardt Blue #3


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Posted

Potassium chlorate 68

Copper oxychloride 14

Red gum 8

Chlorowax 5

Dextrin 5

 

Composition: organic blue star composition.

 

Incompabilities: ammonium compounds and sulfur.

 

It's extremely easily ignited, burns fiercefully and leaves almost no residue. The flame envelope is large and the colour is Forget-me-not blue. It's also quite similar to one of 50AE's compositions. :)

Posted
I will give this comp a try this evening and see how it looks.
Posted

Since I'm in doubt that I will be able to get hold of Paris Green again, I'm in quest of the best potassium chlorate blue. AP is expensive and incompatible with chlorates and potassium nitrate. This one is the best I've tried this far. Shellac will slow the burning down but might produce a hotter and brighter flame. 4% shellac and 4% red gum might be a good compromise.

 

You actually often find two resin fuels in many of Hardt's compositions, though this one originally has dark colophonium in it. I just have 30 grams, bought for about €10 in a music store, and it's in one chunk, of course, so that really doesn't feel like an option.

Posted
The mixture of fuels used in some of the formulas from Hardt (many of which were commercial) is more for economics than performance.
Posted

I know. He even says about one green: "cheap but weak colour".

 

After all copper(II)oxide might be better, but I'll experiment a bit more with the oxychloride. I bought a whole kg of it, also intending to use some of it as a catalyst for whistle mix sometimes when I get a hydraulic press.

Posted
I made some stars with shellac instead. This composition burns so fast that it shouldn't be a problem to slow the burning down a bit.
Posted
Update: I must really promote this one. It burns very good with shellac too. The high burn rate is probably due to the hight percentage of potassium chlorate and the fact that copper oxychloride catalysts its decomposition. Chlorowax burns better than parlon, by the way, at least as small amounts as in this one.
  • 3 weeks later...
Posted

For me chlorowax is more economical than Parlon, because chem shops sell them at a reasonable price. Parlon is just too "special" so only dedicated pyro suppliers would have them whereas chlorowax has industrial uses.

 

I wish there is a good blue star comp using copper sulfate, because copper sulfate is very very cheap and have lots of non pyro uses.

 

Can't do much about reds though, strontium salts are expensive here. Strontium nitrate is the cheapest, while "cheap" strontium carbonate is very expensive. Problem is there are little doubt for its use... only use for Strontium salts beside ceramic is making reds in firework.

Posted

For me chlorowax is more economical than Parlon, because chem shops sell them at a reasonable price. Parlon is just too "special" so only dedicated pyro suppliers would have them whereas chlorowax has industrial uses.

 

I wish there is a good blue star comp using copper sulfate, because copper sulfate is very very cheap and have lots of non pyro uses.

 

Can't do much about reds though, strontium salts are expensive here. Strontium nitrate is the cheapest, while "cheap" strontium carbonate is very expensive. Problem is there are little doubt for its use... only use for Strontium salts beside ceramic is making reds in firework.

 

Unless humidity is a determining factor, use Strontium Nitrate for reds, I like the color better.

 

-dag

Posted
Yes, strontium nitrate is superior. I use it despite the high air humidity here (often over 75% relative air humidity), since you simply can't make that deep red with the carbonate, unless you use AP as the chlorine donor.
Posted

I will use strontium nitrate for reds then.

 

As for copper sulfate, any answers? I think it might be hydroscopic but its so cheap. Even copper chloride is a little expensive (I could make a solution of copper chloride and bubble air through it to turn it into copper oxychloride) so cheaper copper salts would be preferred. Otherwise the only option I can think of with copper sulfate is to turn it into copper benzoate.

Posted (edited)

It is possible to use, but you have to get the water out of it. It has five chrystal waters per molecule: Cu2SO4*5H2O

 

You might heat it in the oven, until it becomes white. Then the chrystal water is out. To prevent it from re-entering, when making the stars, you better bind with shellac and alcohol, not dextrin and water.

Edited by Potassiumchlorate
  • 2 weeks later...
Posted

I tested some more. If you simply use shellac instead of colophonium and stearin, you'll get:

 

Potassium chlorate 64

Copper oxychloride 19

Shellack 7

Chlorowax 5

Dextrin 5

 

This is a bit aqua blue and smells intensely of chlorine. It burns slower than the first variation but still pretty fast.

  • 2 months later...
Posted

I will use strontium nitrate for reds then.

 

As for copper sulfate, any answers? I think it might be hydroscopic but its so cheap. Even copper chloride is a little expensive (I could make a solution of copper chloride and bubble air through it to turn it into copper oxychloride) so cheaper copper salts would be preferred. Otherwise the only option I can think of with copper sulfate is to turn it into copper benzoate.

 

http://www.skylighter.com/fireworks/How-to-make-sky-rockets/copper-salicylate-blue.asp

 

I wonder if a similar process could be used employing CuSO4?

Posted
It will work just the same, though you'll need a different amount of copper sulfate. One thing to be aware of is that sodium sulfate can be kind of a pain to totally wash out of things in my experience.
Posted

I'll work on this one, a blue whistle mix sounds interesting.

Thanks for the head's up on the sodium product!

Posted
From what I've been told these sorts of things don't actually make blue whistle rockets. They'll make blue rockets that fly quite quickly, but do not necessarily have any associated whistle sound to them.
Posted
Hmmm...I'm considering a workaround to avoid the sodium sulfate. I'm thinking salicylic acid can be treated with NH4OH to form the ammonium salt? If I used that for fuel and tried 1-2% CuO for catalyst a blue whistle might be possible. I'm having some difficulty finding information on ammonium salicylate: specifically hygscopicity.
  • 2 months later...
Posted

I finally got some stearin and a new coffee mill. I made another variation with more fuel and a deeper colour:

 

Potassium chlorate 64

Copper oxychloride 19

Red gum 5

Shellac 2

Stearin 2

Chlorowax 5

SGRS 3

 

This burns fast and hot. The stearin seems to have an obvious effect on the burning. The tiny amount of shellac seems to make the flame "purer".

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