Bleser White Mg stars smelling of ammonia

[Potassiumchlorate]

I milled some barium nitrate last year. Since I only have one really good drum for my ballmill (it's homemade), the barium nitrate was slightly impurified with BP.

 

This didn't seem like a problem then, but now, almost a year later, my white Bleser Mg stars smell of ammonia, and I suspect reactions between the sulfur and magnesium somehow releasing hydrogen from the parlon, which then in turn forms ammonia with nitrogen from the nitrates.

 

It's only a few stars left, and it doesn't seem like there's a risk for self-ignition (I keep them away from anything else, though), but the reaction will probably degrade the performance.

 

Or could it be moisture trapped inside them or maybe moisture penetrating the stars from outside? They are rolled and seem very hard. They are not really uniform in size but about 10-12 mm and there is enough of them to fill up at least one 3" shell.

 

The composition is:

 

Barium nitrate 53

Potassium nitrate 12

Magnesium 28

Parlon 7

[Mumbles]

The nitrate was reduced by the magnesium to ammonia. Parlon is not involved. The hydrogen source is water. They've probably attracted water over the year. The reaction is typically hydroxide catalyzed, but water on it's own can do it.

 

8Al + 3NO3(-) + 5OH(-) + 18H2O --> 8Al(OH)4(-) + 3NH3

 

I didn't feel like rebalancing for magnesium, but the reaction is similar.

[Potassiumchlorate]

OK. I keep them in a small container with a lid but the weather here is very rainy except in the winter when it's dry but instead (usually) lots of snow.

 

Thank you, Mumbles.

[Potassiumchlorate]

Update: now my red Mg stars smell of ammonia as well. The question is: does it matter? The white Mg stars still work, when tested in my stargun.

 

I have read in Best of AFN (don't remember which issue of it) that toluen is better suited for this, since it doesn't contain or attract water. Another option would be to use red gum as the binder. Alcohol contains some water as well, but it seems that the key to the problem is that the parlon forms cavities with water in them, which red gum doesn't.

 

The method of making the stars doesn't seem to matter either. The white ones are rolled, the red ones pumped.

[MikeB]

If the stars are degrading dispose of them, burn them, don't take risks.

[Potassiumchlorate]

Yesterday I took the stars out and put them in the sunshine for several hours. The smell of ammonia is gone now. I must also add that I have a very sensitive nose, so that I often smell things that most people can't.

[Potassiumchlorate]

The next time I make Bleser White Mg I'll use magnalium instead of magnesium and phenolic resin instead of parlon. No chlorine is needed for white anyway.

[Potassiumchlorate]

Update: it doesn't work properly with MgAl and phenolic resin. It turns yellow.

[Seymour]

Not terribly surprising, since Phenolic resin is a much richer fuel than Parlon. By weight Parlon is something around 60% chlorine, so that 7% Parlon would be more accurately replaced with more like 3% phenolic resin.

 

The parlon is an interesting addition in a Barium nitrate White. Even with 28% Mg, I'd expect some green to come through.

[Potassiumchlorate]

Not terribly surprising, since Phenolic resin is a much richer fuel than Parlon. By weight Parlon is something around 60% chlorine, so that 7% Parlon would be more accurately replaced with more like 3% phenolic resin.

 

3% phenolic resin seems far too little to bind with.

 

The parlon is an interesting addition in a Barium nitrate White. Even with 28% Mg, I'd expect some green to come through.

 

 

You can see some but not very much. 3-4 stars among 100 or so burn a bit greenish. The parlon is just used as a binder to protect the magnesium, I guess.

[Seymour]

3% phenolic resin seems far too little to bind with.

 

I would not trust it, but having screwed up some comets and bound them with 1%, I actually suspect they'd be usable. I'm not really suggesting it, but just speculating on the oxygen ballance.

 

I'm assuming that carbon is dirtying the flame. Having this happen does not necessarily follow the rules we might expect from stroichiometry, and many formulas are way over fueled with resins but still have a good flame. It could even be the MgAl, and that with 7% Phenolic and Magnesium it might be clean. Way over fueled mixes like this are harder to predict with any precision.

Edited May 28, 2012 by Seymour

[Potassiumchlorate]

I would not trust it, but having screwed up some comets and bound them with 1%, I actually suspect they'd be usable. I'm not really suggesting it, but just speculating on the oxygen ballance.

 

I'm assuming that carbon is dirtying the flame. Having this happen does not necessarily follow the rules we might expect from stroichiometry, and many formulas are way over fueled with resins but still have a good flame. It could even be the MgAl, and that with 7% Phenolic and Magnesium it might be clean. Way over fueled mixes like this are harder to predict with any precision.

 

It has struck me that it could be the MgAl as well. It says magnesium in the composition, and with white it might be an absolute must to use Mg to get white and not yellow.

[Mumbles]

Given this information, it sounds like parlon isn't quite as good at protecting Mg as you may think. It sounds like it's absorbing water, and causing a reaction. It'd take too long to really test, but it'd be interesting to see a linseed oil coated Mg vs. uncoated in a similar situation. You can't use dichromate or dichromate treated Mg in compositions containing barium, so it'd have to be linseed.

[Potassiumchlorate]

I think the water enters already when making the stars. Acetone contains a bit water to start with, and it's extremely moist where I live about 9-10 months a year. You can actually hear a fizzling sound when pouring aceton on large amounts of composition, which is the water reacting with some of the Mg.

 

The best would be to have a press for the Mg stars. Bleser Red Mg is actually just Lancaster's pressed Red Mg with 10% parlon instead of PVC.

[Potassiumchlorate]

*BUMP*

 

I came to think of something: I don't think there is the slightest risk for self-ignition of the stars, but is there any risk that the ammonia might react with the potassium chlorate in the burst charge?

[Potassiumchlorate]

Opinions?