Is it really necessary to coat magnalium stars?

[drtoivowillmann]

Dear Friends:

 

There ist no nead with magnalium. Magnalium ist quite resistant against water.

Never use Boric Acid with magnalium, like you do with pure aluminum. It would become worse.

In professional fireworks Potassium Bichromate coating has been prohibited, because it might cause cancer, although I never have seen anybody eating pyrotechnical stars within their sandwiches. But law is law, at least here in Europe.

As amateur you may continue using it: in most coutries you are illegal anyway. With dichromate the quite stable magnalium-compos become even better.

 

Yours truly: Toivo

[Edwin]

On 10/12/2017 at 6:16 AM, greenlight said:

I havent had any trouble from binding magnalium stars with water at all.

 

It is Magnesium metal that is supposed to be coated because of reactions with water and acids that can be formed. Magnalium is quite stable compared to it I am sure.

What if you used fine mg/al, i.e. -325 mesh in a comp and bind it with water? How about the toro method even?

I was wondering if the smaller particle size will make it react with water more easily and cause color stars to leave an unwanted trail behind.

Edited February 19 by Edwin

[cmjlab]

For stars using KCL04  - Ive used milled Mg/Al (much smaller than -325) recently in both Buel Red and "Buel Green" and have not noticed any heat or other reaction.  I've used it in other colored star formulas and didn't have issue with those either.  All were using dextrin as the binder and water as the solvent. That doesn't mean a reaction couldn't occur, I Believe Shimizu is the one who recommends using dichromate treated Mg/Al and Mg, and of course he would be considered a more "authoritative" source than I.  

Another well respected pyro, especially respected for rockets, recommends adding Boric Acid (at 1%. Solution) to Buel Red, and that goes against commonly understood rule that Boric Acid potentially attacks Mg/Al....

So it really boils down to what you are comfortable doing.  I don't make 20lb batches, I make 2-5 lb batches at a time, and can control any potential heat generation if it happens, and it is small enough of a batch that I get them turned into stars quickly enough that it isn't sitting around in a big mass to produce excess heat (even if it did start).  Plus, I could quickly dispose of the batch if I noticed a reaction starting. I haven't used Boric Acid either, so I can't speak to that.

Now strobe rockets (with AP) are a different discussion.... I use dichromate treated Mg/Al for that, and I think that along with the extra dichromate really helps the strobe reaction, but definitely protects the metal from the AP..  Others likely disagree, but my point being that it's there mainly to protect the metal from AP, not KP.

[cmjlab]

I hadn't heard of protecting the metal to prevent stars from leaving a trail behind.  Maybe you could provide more on your thoughts concerning that one. Your other concerns are certainly legitimate though.

[Zumber]

53 minutes ago, cmjlab said:

For stars using KCL04  - Ive used milled Mg/Al (much smaller than -325) recently in both Buel Red and "Buel Green" and have not noticed any heat or other reaction.  I've used it in other colored star formulas and didn't have issue with those either.  All were using dextrin as the binder and water as the solvent. That doesn't mean a reaction couldn't occur, I Believe Shimizu is the one who recommends using dichromate treated Mg/Al and Mg, and of course he would be considered a more "authoritative" source than I.  

Another well respected pyro, especially respected for rockets, recommends adding Boric Acid (at 1%. Solution) to Buel Red, and that goes against commonly understood rule that Boric Acid potentially attacks Mg/Al....

So it really boils down to what you are comfortable doing.  I don't make 20lb batches, I make 2-5 lb batches at a time, and can control any potential heat generation if it happens, and it is small enough of a batch that I get them turned into stars quickly enough that it isn't sitting around in a big mass to produce excess heat (even if it did start).  Plus, I could quickly dispose of the batch if I noticed a reaction starting. I haven't used Boric Acid either, so I can't speak to that.

Now strobe rockets (with AP) are a different discussion.... I use dichromate treated Mg/Al for that, and I think that along with the extra dichromate really helps the strobe reaction, but definitely protects the metal from the AP..  Others likely disagree, but my point being that it's there mainly to protect the metal from AP, not KP.

I have personal experience my green stars that uses barium nitrate and magnelium reacts in presence of water.

My batch heats up and getting warm.

If I use coated magnelium then there is no issue.

Though theory tells magnelium needs no coating ( Magnesium needs) I believe It reacts to some extents.

[cmjlab]

That's interesting.  Do you make your own Mg/Al or buy it? I make all my own and know the percent alloy is almost exactly 50/50 (assuming alloys were indeed made up of percentages they claim to be).  I wonder if some with more or less Mg tend to react more readily than others....  

Either way, multiple perspectives is good!  

[Edwin]

6 hours ago, cmjlab said:

I hadn't heard of protecting the metal to prevent stars from leaving a trail behind.  Maybe you could provide more on your thoughts concerning that one. Your other concerns are certainly legitimate though.

If I remember right, I was on the fireworks engineering Facebook group and saw a post where some guy was showcasing his red/orange stars. In the comments, a Maltese pyro observed that in that a yellowish trail was being formed and he predicted that it could've been caused from either an excess amount of fuel or the batch of stars was overwet. The guy who posted the videos claimed his mgal was 325 mesh. Yet in Japan, I have seen super clean burning stars (which probably suggests that fine magnalium is used) and they exclusively use the toro method with no problems whatsoever.

 

 

https://www.facebook.com/share/p/ijHVy9EBGwHnLCgW/?mibextid=oFDknk. (if no comments are seen then make it show all comments)

 

"Secondly You can see a yellowish tail to the stars.You have either an excess of some fuel typically parlon or else the metals you are using in the formulas are not fine and/or reactive enough to be consumed in the flame envelope. This typically happens with magnalium if it not fine enough or you are overwetting it in the manufacturing process."

Edited February 19 by Edwin

[Edwin]

Marugo, a very famous fireworks manufacturer from Japan makes stars like the following

(Timestamp 3:26, look at the pillar mines)

And here is how they make their stars (A whitish grey comp suggests that it is a color comp.)

(Timestamp 3:04)

 

Btw the channel that posted the second video is a great source because the person has close ties with marugo and they posted multiple videos of the inner workings of their factory.

 

 

Edited February 19 by Edwin

[Zumber]

6 hours ago, cmjlab said:

That's interesting.  Do you make your own Mg/Al or buy it? I make all my own and know the percent alloy is almost exactly 50/50 (assuming alloys were indeed made up of percentages they claim to be).  I wonder if some with more or less Mg tend to react more readily than others....  

Either way, multiple perspectives is good!  

No  I dont make. I purchase it.

And I know these days proportions are not 50:50  Insted more aluminium than magnesium is used these days as scrap price are increased a lot.

Two tyoes are available

Coated magnelium and uncoated magnelium.

[Zumber]

43 minutes ago, Edwin said:

If I remember right, I was on the fireworks engineering Facebook group and saw a post where some guy was showcasing his red/orange stars. In the comments, a Maltese pyro observed that in that a yellowish trail was being formed and he predicted that it could've been caused from either an excess amount of fuel or the batch of stars was overwet. The guy who posted the videos claimed his mgal was 325 mesh. Yet in Japan, I have seen super clean burning stars (which probably suggests that fine magnalium is used) and they exclusively use the toro method with no problems whatsoever.

 

 

https://www.facebook.com/share/p/ijHVy9EBGwHnLCgW/?mibextid=oFDknk. (if no comments are seen then make it show all comments)

 

"Secondly You can see a yellowish tail to the stars.You have either an excess of some fuel typically parlon or else the metals you are using in the formulas are not fine and/or reactive enough to be consumed in the flame envelope. This typically happens with magnalium if it not fine enough or you are overwetting it in the manufacturing process."

Tail also comes from fine metal if it is excess in quantity and uf it is not consumed by flame and if it is in motlen state even excess amount of 400 mesh plus fine aluminium leaves tail behind it.

Tail is certainly not from coating it is from metals present in compositions.

[Crazy Swede]

But if there is metal in excess you should end up with a silver tail. In this case it was looking like yellowish slag.

[cmjlab]

You guys have an outstanding eye for detail, I'm blind, or I need to pull it up on a laptop because I don't see what we're talking about, lol.  

To be clear, these are the mines we are referring to?

[cmjlab]

One more screen grab (I see white/silver/maybe yellowish tail).

 

[Edwin]

31 minutes ago, cmjlab said:

You guys have an outstanding eye for detail, I'm blind, or I need to pull it up on a laptop because I don't see what we're talking about, lol.  

To be clear, these are the mines we are referring to?

Yes, this is an example of what I'm shooting for. Btw I don't know if it's just me but these colors kinda remind me of Ned's nx colors. 

Edited February 19 by Edwin

[Edwin]

28 minutes ago, cmjlab said:

One more screen grab (I see white/silver/maybe yellowish tail).

 

Marugo's blue stars are a bit slaggy at times. Sometimes I see them burn super clearly yet, and sometimes it's slaggy, probably just depends on camera exposure.

1:17

Three layer kaleidescope shells

You can see the leftmost shell, the stars closest to the nucleus of the break are blue and they leave behind some slag. The other colors are just fine.

The shells are made by the same company as the mines.

 

Edited February 19 by Edwin

[Edwin]

55 minutes ago, Crazy Swede said:

But if there is metal in excess you should end up with a silver tail. In this case it was looking like yellowish slag.

Yes, the slag is what I want to avoid.

Edited February 19 by Edwin

[Zumber]

1 hour ago, Crazy Swede said:

But if there is metal in excess you should end up with a silver tail. In this case it was looking like yellowish slag.

It depends on burning characteristics of stars even aluminium leaves yellowish tail.

Choise of oxidizer is important too.

If star burns very bright white flame colour and if temperature is to high you will end up with silver tail.

[cmjlab]

57 minutes ago, Edwin said:

Yes, the slag is what I want to avoid.

I see what you're saying and wanted to make sure I was referring to the same thing before talking about it 

IMO that looks like a combination of prime burning off, and metal spark trail.  Some Titanium will leave a yellowish color trail, depending on the manufacturing process (credit for this goes to Mike Swisher - I've observed it, but not know why some is yellowish and some is silver until he explained).

Additionally in the stars in your second post, I see multiple types / sizes of stars being fired from the shell, with smaller stars trailing the larger stars (but easily identified as they remain in groups even as the larger separate from the smaller stars).  To me, all that makes sense from the perspective that larger will fly further than smaller.

I'm not saying you are wrong (I'm not an expert at any of this), maybe/probably I'm wrong (I've been wrong many times before and will many more), but that is what I saw when I watched the videos. I've not had a chance to pull it up  on a bigger screen yet, which I will do later.

[Edwin]

2 hours ago, Zumber said:

It depends on burning characteristics of stars even aluminium leaves yellowish tail.

Choise of oxidizer is important too.

If star burns very bright white flame colour and if temperature is to high you will end up with silver tail.

Now can water cause magnalium to react slightly and cause it to produce a tail in color stars like how Adrian said in his Facebook comment?

[Zumber]

Chemically what is tail?

It is molten drop of metal when travels faster in air it leaves sparks ( tail)

It has nothing to do with water reaction with magnelium to produce tail.

If there is tail it is due to metal ( magnelium aluminium and so on...)

[Crazy Swede]

A disturbing and bad looking tail, that I think we were talking about from the beginning, comes from an unbalanced formula that CAN be a result from chemical degradation. 

If some magnalium is lost due to corrosion, inert material is formed that could contribute to less cleaner burn and short tails  

Otherwise, chlorinated rubber is notorious for leaving a short ugly tail of yellow slag/cinders. 

A tail should always be intentional, fine grained and good looking. Otherwise it is a fault in my opinion. 

[Edwin]

6 hours ago, Crazy Swede said:

A disturbing and bad looking tail, that I think we were talking about from the beginning, comes from an unbalanced formula that CAN be a result from chemical degradation. 

If some magnalium is lost due to corrosion, inert material is formed that could contribute to less cleaner burn and short tails  

Otherwise, chlorinated rubber is notorious for leaving a short ugly tail of yellow slag/cinders. 

A tail should always be intentional, fine grained and good looking. Otherwise it is a fault in my opinion. 

Yes, I didn't specify but that is exactly what I'm talking about about.

So I feel like I be better off coating just to play it safe. Regarding what is used to coat the magnalium, I will be referring to the Fireworks Engineering Facebook group again. Jorge Ferrando, a prominent member in the group, showed in a video of him using silicone oil lubricant dissolved in Methyl ethyl ketone to coat his magnesium, not magnalium. I think he claimed that it works better than linseed oil but I am not too sure if he said that or not. I will just assume that it works for magnalium as well.

Now has anybody tried or even heard of using silicone oil to coat metals?

Edited February 20 by Edwin

[Crazy Swede]

I have heard about it, and you can be magnesium powder pre-treated with it, but I have never evaluated it myself.

It sure would be an easy method for protection against corrosion, but I guess it must be very important not to use more than the metal powder can tight hold to itself. Otherwise, the silicon oil will start to creep and could possibly ruin the ignition layer on a star, comet or flare.

Linseed oil is good since it polymerises and will not escape to places where it does not belong after curing. 

[Edwin]

14 minutes ago, Crazy Swede said:

I have heard about it, and you can be magnesium powder pre-treated with it, but I have never evaluated it myself.

It sure would be an easy method for protection against corrosion, but I guess it must be very important not to use more than the metal powder can tight hold to itself. Otherwise, the silicon oil will start to creep and could possibly ruin the ignition layer on a star, comet or flare.

Linseed oil is good since it polymerises and will not escape to places where it does not belong after curing. 

Jorge demonstrated with just pouring the solution into the metal and making a dough. It is then dried as clumps. Once dry, would these clumps be easy to break? Would it be the same with linseed oil?

[Crazy Swede]

Silicon oil would not dry out, unless it was diluted in some solvent, so the clumps would be very soft. I get the feeling something else was used than ordinary silicon oil.

I can ask him!