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Problems with green stars


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#1 pyrogenius007

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Posted 14 April 2019 - 07:48 AM

Hi,                                                                                                                                                                                                                         Guys I am having problems with my green stars, I have tried many formulas which contain either chlorinated rubber or cpvdc as the chlorine donor. I have access to PVC only, which, when compared to the above donors has a much lesser chlorine content  I guess this is the reason why I get a pale or yellowish green. I use combinations which have Baruim Nitrate, Pot.Chlorate,(I use only LR grade) Magnesium,(coated with wax) and pvc in place of  Parlon or Saran, both of which are unavailable in small quantities where I live, since they are used as raw materials, the min. order quantity is around 50 kgs. I also have some cpvc adhesive glue which contains acetone, m.e.k and other solvents along with cpvc and silica. Will the presence of silica affect the result of the color ? or will it result in any unwanted reaction.                                                                                                                                                                                                                   

I had a small quantity of Barium Chlorate which when combined with shellac gave off a deep green. I have run out of it and now it is not available in India. I  have read that it can be made through electrolysis process, has any one tried it ? if so what is the process, mainly,is it   safe to do it ? Any info. regarding the above topic will be greatly appreciated.                                                                                           

                                                                                                                                                                                                                             Thanks,                                                                                                                                                                                                                                                                                                                                                                                                                                           PG.007



#2 Mumbles

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Posted 14 April 2019 - 11:59 AM

Are you burning the compositions as a powder or bound into stars? Many formulas only give a true flame color once bound.

Outside of that, could you give some example formulas you've been Uzi g or trying to modify?
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Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

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#3 davidh

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Posted 14 April 2019 - 12:51 PM

Are your stars completely dry? I once had a batch of green stars that burned yellow. I put them up for several weeks, and then tested them again. I was shocked by how green they had become.


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#4 pyrogenius007

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Posted 15 April 2019 - 02:34 AM

Mumbles and Davidh, thanks for your reply, I will make stars and then try them out on the ground as well as in a mine and let you know the results. The composition I tried was Barium Nitrate 42 gms, Pot.Chlorate 16 gms. Magnesium 25 gms. PVC 15 gms. Lamp Black 2 gms. I also had binding problems with this mix. I used the same chemicals for red by replacing the Barium with Strontium Nitrate, added some THF to it, the PVC dissolved well and acted as a binder. However, the green comp, was crumbly, I added a little CPVC glue to it and it bound fairly well, still the result was a washed out green. I have also tried out other compositions containing Baruim Nitrate, Magnesium and PVC, but as you mentioned I will make stars with them and try them out. What are your opinions on using CPVC glue as a binder and chlorine donor.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Thanks,                                                                                                                                                                                                                                                           PG 007                                                                                                                                                                                                                                                                                                                                                                      



#5 Carbon796

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Posted 15 April 2019 - 11:00 PM

Cpvc glue may have adulterants/fillers in it, that could affect the color negatively.

There's also so much magnesium metal fuel in that comp that it probably does look washed out, up close on the ground. Greens can be like blues, too much metal fuel isn't necessarily a good thing. They are not a really saturated color like reds, oranges, and yellows can be.

I'd also drop the lampblack, thats not going to help the green any. As well as the wax, if your solvent binding them.

#6 pyrogenius007

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Posted 16 April 2019 - 01:33 AM

Carbon796, As you have suggested I will cut down on the magnesium by about 3% and use it without wax coating, I have some shellac which I will use as a binder. I will post the results as soon as I get it right. Thanks for your suggestions.                                                                                                                                                                                                                                                                                                                                                                                                                                           PG007



#7 Carbon796

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Posted 17 April 2019 - 09:37 PM

A 3% reduction in the magnesium content probably wont even be noticeable.

Bleser's nitrate mag red, which is a modification of Lancaster's, is

.55 strontium nitrate
.28 magnesium
.10 parlon
.07 pvc

Versus the green equivalent, for example

.55 barium nitrate
.18 magnesium
.15 pvc
.12 parlon

Also note, that Bleser recommends solvent binding with the parlon.

Your above posted formula is also severely oxygen deficient, ruffly supplying 19 grams oxygen, while needing 46+ grams oxygen for complete combustion.

If you cut your magnesium down to 10 grams, and doubled your barium nitrate to 84 grams, your oxygen balance would be alot closer. Plus you'd get rid of an excessive amout of mag, and add additional barium, which will also improve the color. I'm not saying this would be an ideal modification, but it should at least look green then.

Edited by Carbon796, 17 April 2019 - 10:22 PM.


#8 Arthur

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Posted 18 April 2019 - 12:31 AM

http://www.thegreenm.../pfp/stars.html

 

Is one web iteration of a well researched list of star compounds. Pick one and use it exactly. Not all comps transfer from colour to colour perfectly. 

 

Older (historic) compounds will use chemicals from different lists, as new and better compounds became available and the hazards of mercury lead and arsenic compounds became apparent.

 

Usually star comps only perform properly when fully dry and actually passing through air at a great speed.

 

Some stars are actually given a production method, or specified solvent, sometimes this is historic sometimes it is essential.

 

Most certainly NOT all star comps and their changes and substitutions are successful.


Edited by Arthur, 18 April 2019 - 12:36 AM.





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