Help with green star

[Merlin]

I have not been able to make cut green stars ( they turn out yellow) using this formula. It seems to me there should be some dark aluminum in the formula somewhere. Any suggestions for cut green stars appreciated.

Potassium perchlorate 3

Magnalium 3

Barium Carbonate 2

Parlon 0.15

Red Gum 0.05

Edited August 20, 2014 by Merlin

[nath0r]

No dark aluminium is required in this formula. I've used this formula a few times and never had any problems. Are your chemicals free from contamination?

Edited August 20, 2014 by nath0r

[dagabu]

Bad Perc?

[Sparx88]

http://mushroompyro.weebly.com/star-comps.html

 

scroll down to hardt green #5 or shimizu green. I use both and they are nice. I lean towards the hardt #5 myself.

[Jakenbake]

I'm with sparx on this one. A much better green can be found with barium nitrate.

[Mumbles]

I use something very similar, and it works fine. I suggest you check your chemicals for contamination. The formula you posted is a haphazard roundoff of a commercial formula. Maybe that has something to do with it? I included it below. It's from Dave Buell.

 

Perc - 35

BaCO3 - 25

MgAl - 14

Parlon - 13

Red Gum - 7

Dextrin - 4

 

Note: This only adds to 99 since it's an approximation of a commercial formula.

[FLMark]

I've been having a similar problem with my green stars as well- I tried the brilliant red formula substituting BaNo3, I tried The Fish MgAl star formula, and several similar variations, and I get a brilliant yellow star every time. All Chems are from a reputable pyro supplier. Thoughts?

[FlaMtnBkr]

Are you using water to cut them? If so is it distilled?

 

Really need to know your exact process and everything that is going into them. But most likely you have some sodium contamination in something. But green can be the hardest color to get working. However, if the green rubber/parlon stars made with acetone and barium nitrate aren't giving you a nice green there is definitely something that isn't pure.

[FLMark]

Thanks so much for your response- I've been following the skylighter screen sliced rubber stars method pretty carefully, using only acetone (albeit old acetone) as a solvent. I'm using the two step priming process from the rubber star guide. I've also tried just burning some raw star comp with no solvent, and that was bright yellow as well. The MgAl was 325 mesh and the barium nitrate is also finely powdered, both from HCS. Thanks for any suggestions!

[FlaMtnBkr]

Where did the parlon and red gum come from? Have you tried using strontium nitrate and did you get a deep red?

[taiwanluthiers]

Could this be flame temp too low? Barium likes hot flames it seems, but honestly I've never gotten barium carbonate based stars to work right. Either very little green or yellow flames. Barium nitrate works very well on the other hand. If the flame is orange, it's sodium. It doesn't take much sodium to ruin colors either.

[FLMark]

The Parlon and red gum are both from Hobby Chem supply as well. I'm considering buying some barium carbonate from a local pottery supply to see if the barium nitrate that I've been using is the problem. I made brilliant red stars using a direct substitution with Strontium nitrate, and they worked great... I've also made blue lactose stars as well, and they also worked fine. I'm glad to hear I'm not the only one who has had to figure this out

[Mumbles]

Sometimes looking at the star directly wont give an accurate impression of the true color. You may want to try them in a mine, or look at the reflected light. My work area had light colored walls, and the light on the wall would give a more true representation of what I'd expect in the air. I'm not saying this is your issue, but just a somewhat related suggestion.

 

I've heard more than one person raise this issue as of late. I wonder if there might be a bad batch going around. I don't off hand know of anyone selling the barium nitrate that Barium and Chemicals produces, which is one of the best quality. Pyro Chem Source does sell their barium carbonate though.

 

http://pyrochemsource.com/Barium-Carbonate-BARIUM-CARB.htm?categoryId=-1

[Carbon796]

I've had bad barium nitrate before, but not from HCS. Not that it couldn't happen. You may want too make a small sample batch. To confirm you didn't make a mistake during processing, weighing/screening. You could also purchase barium nitrate from another company like PCS to compare it to.

[FLMark]

Thanks again for all the help- I'm going to try viewing the stars from a few more angles (I've been using a star gun, might try 4 or 5 in a rocket header to get a better view from a distance), and I'm also going to try a few additional small batches to make sure I've been consistent with measurements. If that doesn't work, I'll probably pick up a pound each of BaNo3 and BaCo3 from another supplier to compare. If it is the nitrate, I think it's just a fluke, as everything else that I've gotten from HCS in the past has been great.

[psyco_1322]

If all the other chems have been used to make good colors, and the red variant doesn't seem defective, I'd say you have some bad barium nitrate. The green should be unmistakable, even on the ground. Get with your supplier and see about a refund or replacement chems.

[Livingston]

Barium nitrate based always works for me and has come from PCS... I always double check measurements and through mix the formula. They roll real easily. I rather roll the. Cut any day!

[FLMark]

Hi guys, got a quick update... Got some granular Barium Nitrate from Pyro Chem source, milled it thoroughly, and the stars turned out great! Blinding bright green with no hint of yellow. Thanks for all the help! Edited December 4, 2014 by FLMark

[dagabu]

Just don't breath it and wear gloves. I got a little in me some years back and I got sick as a dog.

[FlaMtnBkr]

I would tell the original source that his product has an issue. He might even give you a credit.

[Merlin]

This is the green formula I use primed with hot ignitor prime and then meal-d.

Hardt Green Star #5 Barium nitrate 56 Red gum 7 Magnalium -200 mesh 17 PVC 15 Dextrin 5 Add 25% alcohol / 75% water

[FLMark]

Thank you guys for both of those suggestions- I've been using gloves and a respirator and haven't had any issues so far, just gotta remember to not get too comfortable working with it. I'll shoot my original supplier an e-mail to make sure he's aware of any potential problems there might be with his stock.

[gregh]

This post is probably a little late since his problem is solved, but chemicals that produce red or orange flames will make the greens look yellow. The mixing of the green and red light makes yellow. Even the smallest contamination of one of those chemicals would definitely change the color. That is the principle behind the Veline and Gorski color methods, instead of using an individual chemical to product a yellow, like cryolite or a sodium compound.

[FlaMtnBkr]

I find it funny that so much is attributed to Ned. He is a great guy and makes some awesome fireworks. But he comes up with very little and mainly uses and shares others' techniques and formula. The rubber star colors were, to my knowledge, originally conceived by Troy Fish, perfected by Gary Smith, and shared by Ned.

[calebkessinger]

Hey Bkr,

I think Ned has a way of extracting information and putting it in laymans terms very comfortable. Mike S. and others have a never ending knowledge of fireworks but don't have the same ability to convert such to something everyone can understand and do. Yes you can get the answer from them if you know what (exactly you want to know) and are able to siphon out the actual truth behind it for it is usually an unexplained answer. A lot of the times some will answer questions and give examples without explaining the reasons or the formula to get there. Like an algebra teacher just telling you the answer to a complex equasion without telling you the formula. Yeah you got your answer but you're not the least bit smarter or able to understand it. I would describe Ned as a person who will set down whatever he is working on and (Gently) explain what works for him and why, People respond to his attitude with Joy and respect even if he isn't the inventer of things,

I know when I go to the hardware store and someone knowledgable helps me and guides me to what I need I love them for it, I know they didn't make those things I need, Heck sometimes I go to the store and find a crazy person with purple hair is stationed to help me!! But when you need help getting something fixed and that person is kind, honest, and willing to stand beside you gently explaining what you need no matter who you are, That person will always be remembered and respected.

 

Just some thoughts, Caleb

Edited December 4, 2014 by calebkessinger