Magnalium and Potassium Dichromate

[PhoenixRising]

Just got some magnalium on order and I'm going after Win39j. I was hoping to clear up a few things in this thread that I feel like I've read somewhere before but seem unable to locate right now.

 

As I understand it, the 2 most common ways of protecting Magnalium from a reaction with Nitrates is to use either boiled Linseed oil or Potassium Dichromate; the later being the prefered method.

 

My first question is: What's the best way to coat Magnalium (or Magnesium) with Dichromate?

 

And my second question is: With using such little water to bind glitter (6-8%), is it absolutely necessary to coat the Magnalium in such case?

 

Are my stars going to spontaneously catch fire before I have a chance to use them?

From what I "think" I read in the past, the problem of nitrate reaction is not as bad in small batches, and that "sometimes" the dichromate isn't needed?

 

TO BE CLEAR HERE: I just ordered a pound of dichromate... like literally as I was typing this, it's been eating at me all day like a bad nitrate reaction.. er umm.. you know.

 

I WILL be using dichromate in the future as soon as it arrives, but before then I was playing with the idea of doing a small test batch (50g), because like a boy with a new toy it's going to be so hard to let that magnalium just sit around for more than 2 days. But I will wait if I have to.... hard as it may be. Thanks for taking the time to read this.

Edited June 1, 2016 by PhoenixRising

[lloyd]

Phoenix,

 

Just use the dichromate solution as your star wetting or rolling 'water'.

 

Works a treat! Dissolve what you can AT ROOM TEMPERATURE in the water you roll with. That's all you need to do!

 

Lloyd

[pyrokid]

In small batch size and with small amounts of water, reaction between nitrate and metal has never been a problem for me.

[PhoenixRising]

Well snap, that's as easy as can be, thanks Lloyd!

 

Guess that means I'll be labeling a new water bottle with "xxx" and "do not drink" .... "keep away from the cat" .... "not for jogging" "or hiking"

 

After reading through all the safety literature I could recently, the last thing I ever want is to be worried about the comp I'm currently fooling with. I want to "know" that it's been done before with good results. That being said, I've never noticed a nitrate reaction with any aluminums yet, but something about the word 'Magnesium' gives me the willies a bit. I may hold off a few days, pretty sure Harry will ship my stuff fairly soon. Magnal doesn't get here for another couple days.

 

Thanks again guys.

Edited June 1, 2016 by PhoenixRising

[lloyd]

I might add that it's not necessary unless you suspect metal/water reactions. I certainly would NOT use dichromate-water to moisten charcoal stars! <G>

 

(I only say that for the 'general membership'. I figure you could discern that yourself!)

 

Lloyd

[Mumbles]

Also, dichromate solutions are bright orange. It'll be easier to confuse it with kool-aid than water.

 

I've never had much of a problem with MgAl reacting in glitters even when cutting. I however do not heat them, just ambient air, and I don't use boric acid. Boric acid, while protecting aluminum will attack Mg. I made both mistakes at the same time for some comets I entered at PGI. They burned okay, but the tail was a fraction of what it should have been. The coarser MgAl in Win 39j is less prone to react as well.

[Seymour]

To be honest, I've never used linseed oil for coating metals, or actually, anything at all, but I did think that linseed oil was considered superior for almost all uses of Mg and MgAl, with only Ammonium perchlorate containing compositions being the exception, where dichromate is more effective. My source for this info is Shimizu's F.A.S.T, and admittedly only five or six oxidisers were tested with Mg of the two treatments.

 

I understand that dichromate works pretty well with all common pyro oxidisers (Barium nitrate being an exception due to the solubility of Barium dichromate being so low that the dichromate is precipitated out of action if I remember correctly) and is probably easier to use than linseed oil, and thus is a good choice for general use over linseed oil. Is it that Dichromate is considered overall superior because of convenience (and the AP factor), or is Shimizu's analysis misleading, or just out of date after all these years?

[lloyd]

Seymore, it's mostly the convenience issue, coupled with the fact that it works 'well enough' for almost all needs.

 

Coating with linseed oil is a LOT of work, and takes a great deal of time. That, and it's nigh-on impossible to find honest-to-goodness real boiled linseed oil, anymore.

 

Lloyd

Edited June 1, 2016 by lloyd

[PhoenixRising]

So I shouldn't moisten charcoal stars with it? But I thought it was impossible to be 'too safe.' (kidding! Thanks for the extra clarification, even if I personally didn't need it.)

 

Mumbles, what you're saying is I shouldn't buy orange Powerade for a little while? I hate orange flavor anyway.

 

Thank you for clarifying not to use Boric Acid with Magnal, that was actually SUPPOSED to be my 3rd question yesterday but I completely forgot to ask. I know there will be barium carbonate in the mix as well (Win39j) and was a bit tossed up as to what to do about PH.

 

I know dichromate is rather poisonous, and I will be wearing nitrile gloves while handling the stuff. (Or at least until the stars get a good layer of prime)

 

Yesterday I was a bit hesitant to post this question as I was almost embarrassed that I didn't know the answer, knowing I've read this info somewhere else before. No worries though, I made sure all the tags on this post pertain directly to Magnal and Nitrate safety. At least it will be easier searching for future parties. Thanks for not beating on me, I do happen to like this place a lot.

[CrossOut]

All glitter comps I've worked with are stubborn to over wetting. To much water while rolling makes the star producce significantly less sparks. I imagine to much water makes the oxidizer soak into the charcoal increasing burn rate but I could be wrong here as it doesn't account for the metal based glitters.. For best results I recommend pressing your stars using 2-3% water or rolling if you are good at it. Wetting and cutting is my least recommended method for glitters. Edited June 7, 2016 by CrossOut