18 replies to this topic

[vaslop2005]

Hi guys,
I am new to the world of pyro forums and would like to ask for some advice from you experienced hobbyists.

I've been making small scale fireworks, and experimenting with colour formulas. making many of my own formulations for interesting effects, untill recently (when I got back into pyro after 6 months of leaving it) for a reason unknown to me, all my blues stopped working (even the usually great Conkling #1). I've tried to eliminate as many variables in my chemicals as I can, without fruition.

KClO4--66.1 CuO--13.4 Parlon--10.7 Red gum--9.8 Dextrin--5

I recrystallized my KClO4, and even bought some new stock, I've tried two separate batches of copper oxide, and even replaced the oxide with carbonate, I tried excluding the dextrin. Leaving only the parlon or red gum.

am I missing something? or is it just something I'm doing?

Thanks

[pyrotechnist]

Try using hexamine instead as it is a cooler fuel with the added bonus of increasing the flame envelope.

[vaslop2005]

Try using hexamine instead as it is a cooler fuel with the added bonus of increasing the flame envelope.

I will try this. But does anyone know why this is becoming a problem? or has anyone else had this problem before?

[a_bab]

Please post more info. What does it mean your blue stopped working? Is it greenish? Or maybe it's a washed out blue? Did you observe it from distance or from close?


Did you notice that lately all the things that usually appeared as blue turned to (insert color here)

[vaslop2005]

at first (about a year ago) they would happily burn blue, sitting on a log outside, and in the last month, (since I've replaced my parlon and red gum) they've been washed out.

This does seem to point the finger at those two chemicals, but I am skeptical that these can be contaminated, especially as they are new and from Steve Hall, who has been very good in the past...

[a_bab]

Blue is an extremly sensitive color to any contaminant. I'd red gum with something else (xexamine, lactose) as sugested before (even plain sugar will do, as it's free of sodium, albeit not good in a real star).

[vaslop2005]

I am half way through drying some shellac blue stars... no idea whether they will work, I'll post back when theyre done,

[maxman]

Are the stars rolled pumped or cut? I have heard of a problem with some parlon whilst rolling stars. What happens is that if the parlon not ALL very fine mesh, then the larger particles seperate and are all picked up at the end of rolling as the star is at its full size. This has the effect of insulating the star from fire and making it very hard to light.

Maxman

[vaslop2005]

actually, I was just about to start rolling some, but I have been cutting and noticed a similar kind of thing, where the red gum came to the surface sometimes during drying.
but ill watch out for that. is their any was around this problem with rolling?

Edited by vaslop2005, 20 June 2010 - 09:19 PM.

[Potassium chlorate]

actually, I was just about to start rolling some, but I have been cutting and noticed a similar kind of thing, where the red gum came to the surface sometimes during drying.
but ill watch out for that. is their any was around this problem with rolling?

Rolling stars with parlon is pretty difficult. It's difficult both if you use the parlon itself as a binder or any other binder. Though it's a very nice chlorine donor.

[seymour]

Rolling stars using Parlon as the binder is not easy, but I've successfully done it.

Rolling stars containing Parlon, using Dextrin, or Gum Arabic as the binder has never been a problem in my experience. Certainly, it is easier than some of the very high charcoal content streamers... Not that they are too hard to roll if you are careful with the water content.

Has something happened to your scales?? Blues can be very sensitive to the change in oxygen ballance. Too much oxygen and copper oxide forms which emits a redish light. Too little oxygen and carbon particles are formed by incomplete combustion which wash colours out by poluting the flame. This affects all colours, but blues more than most. If your scales are now becoming senile, this could be the problem.

Playing with fuels is not a bad idea, I certainly like to do it a lot, however you can not expect success if you do it randomly. Replacing Red Gum, Lactose, Hexamine or Rosin with one another can improve colours quite a lot in some situations, but they are different chemicals. Each has a different ratio of carbon to hydrogen, and oxygen or nitrogen, which means that each requires different quantities of oxygen per gram of fuel to burn.

If you replace a lactose burning blue 1 to 1 with rosin, there is a very good chance that you will get carbon in the flame, since rosin is much richer as a carbon source and demands more oxygen. The same applies to different fuels (sometimes in reverse) to greater or lesser extents.

I suggest replacing fuels by comparing the empirical formulas of both, and by calculating the oxygen demands of both so that with a little maths you can produce a ratio with which to swap them and have a greater chance of success.

Carbon based fuels can burn with the carbon going to CO or CO2, or any mixture of the two. This spices things up and makes it more fun!

[vaslop2005]

Ahha! now I did buy some new scales, and they could easily be the problem... (they are from china, and I payed £10 for scales that weigh to 1/100th of a gram, which I thought was unbelievable)

can anybody recommend a set of scales, or a place to buy them, as I don't wish to pay more money for another lost cause.

And I did have a look at some exotic fuels, as well as red gum, sugar and shellac. I made some copper benzoate, copper aspirinate (an amazing turquoise powder) and copper sorbate (which looks very promising as it has a few oxygen atoms in the molecule, and fewer hydrogen and carbon atoms than the readily used benzoate salt, so burning cooler and bluer in theory). But they all failed miserably

Thanks

[maxman]

Why not just try a known weight on your scales? as they might be ok.

Maxman

[digger]

I made some copper benzoate, copper aspirinate (an amazing turquoise powder) and copper sorbate (which looks very promising as it has a few oxygen atoms in the molecule, and fewer hydrogen and carbon atoms than the readily used benzoate salt, so burning cooler and bluer in theory). But they all failed miserably

I found that copper benzoate / copper sorbate make for very good blues with AP. With KP it did tend to burn too quickly.

[Mumbles]

Red Gum is a natural product, it certainly can be contaminated. If you're not screening your chemicals you may want to try that. Somewhere between a 60 and 100 mesh screen will remove a lot of the crap from red gum, as well as the larger particles from parlon. Your perc sounds fine, CuO is usually pretty good even the ceramic grades. Parlon is only comes from one or two sources in the world so it is probably alright. I'd focus on the red gum personally. You may want to dissolve some in alcohol, and see if there is a substantial amount of insoluble material. Not all red gum is created equally.

The formula you're using should be fine. It's the same one I use, and it's one of the nicest KP blues I've seen.

You may want to try the stars in the air before getting too disappointed. You may just be remembering them more favorably than they really were (unless you have video comparisons).