Green Stars without Barium

[hindsight]

Bobosan, Thanks. Yes, this is the same information from the Skylighter link that Nater provided. Sent Hunter a PM about the copper powder and waiting for reply.

[WSM]

Nater, Amazingly, you keep providing good sources of star formulas matching my desires and limitations. Thank you, sir.

These are the non-barium green stars listed in the Skylighter link:

From Christian Brechbuehler - Jun 15 1993

Potassium perchlorate 70, Fimo [PVC "clay"] 20, Copper 10

Green

Potassium nitrate 15, Sulfur 2, Airfloat charcoal 1, Copper powder 4, Red gum 1, Dextrin 1

Bobosan, I will send Hunter a PM requesting copper powder. But the last time I whispered something on a post about the KBenz he was selling, he was sending me a PM.

Have to learn about "Fimo [PVC clay]" and where to get it.

 

If you're in the US, go to an art supply store and look for "Sculpy" modeling compound. It's PVC based but has a fair amount of calcium in it. It makes orange colored effects on its own.

 

WSM

[hindsight]

Apparently, Fimo can be purchased in Europe from Staedtler Mars GMBH, Königstraße 15, 90402 Nürnberg, Deutschland, but which product is the proper one to use: Professional, Soft, Classic or Effect? And does color matter?

[WSM]

Apparently, Fimo can be purchased in Europe from Staedtler Mars GMBH, Königstraße 15, 90402 Nürnberg, Deutschland, but which product is the proper one to use: Professional, Soft, Classic or Effect? And does color matter?

 

I like your tag line. It reminds me of the answer to, "What do you get when you make something Foolproof?"

 

Answer: "More creative fools!"

 

WSM

[hindsight]

Yes, WSM, I get more creative in my foolishness (or more foolish in my creativity) every year, which probably explains why I am trying to make pyrotechnic stars out of children's modeling clay. I see myself aging like a fine cheese, like Limburger or Port Salut...and that is foolproof, because who can say when stinky cheese has gone bad?

 

Now back to the topic....

 

If anyone has experience with using PVC clays to make stars, please explain whether it is simply a matter of kneading the clay with the KClO4 and Cu powder. Does it harden spontaneously, or is mild heat required?

Edited July 21, 2014 by hindsight

[Mumbles]

There is a little information in Best of AFN 3 on pages 93 and 94. Fimo is said to be a little stiffer than Sculpey, thought they are similar. Essentially, they're just fine PVC, plasticizers, and fillers. It's stable at room temperature indefinitely, or it can be heated to 275-300F for a few minutes to harden it permantantly. BAFN makes it seem like the clay is just mixed with the powered ingredients and not cured. They seem to be using it more as a rocketry propellant though.

 

Not curing the stars would seem to prevent their use as actual stars since they'd be too soft. Based on the way it works, it doesn't sound like there is any other way than heat to cure the stuff.

 

These clays are basically plastisol with calcium carbonate filler. BAFN mentions that it would probably be best to get plastisol just use perchlorates and fuels as the filling agents. This method has been investigated as a way to make rocket engines.

 

http://en.wikipedia.org/wiki/Plastisol

[hindsight]

Good information, Mumbles, thank you. The wiki says heating plastisol to 177C (350F) dissolves the components and it hardens on cooling. But if 275F may accomplish the hardening of plastisol+filler (i.e., the clays) that may be more practicable. Until copper powder and the clay are in my possession, this a theoretical discussion, and there is time to consider the potential hazards of heating oxidizer and fuel together. It sounds impractical to heat plastisol/KClO4/Cu, and pour it into a mold to cool and harden, but it is intriguing. The clay would be cut or pumped and then heated, it seems.

[Mumbles]

I'm seeing all sorts of values. Everything from 170F to 350F. 275F is what is recommended on the Sculpey website for 15min per 1/4" thickness. It might just be a time vs. temperature thing. Lower temperatures just dissolve less, so it takes longer to fully cure. I even found some information that would make it seem like normal pyro drying procedures might work. A drying box, or some enhanced sun drying might do the trick in an afternoon or overnight.

 

https://www.og13.com/forums/showthread.php?975-New-trick-for-hardening-sculpey-on-figures

[hindsight]

Understood, Mumbles. This adds incentive to constructing a drying box. I have found a source of Sculpey and Fimo brand polymer clays. Perhaps Fimo Effect uncolored "Translucent" grade has the east amount of additive which may (or may not) interfere with star color/performance, so I will try that type. Hunter has not responded to the request for copper powder, so I assume he is busy at the moment. I do not know the appropriate mesh size, but am looking for a source of copper powder.

 

 

 

 

Edit: There is a supplier of copper powder 325 and 400 mesh locally; it should arrive in a couple days.

Edited July 22, 2014 by hindsight

[hindsight]

From Christian Brechbuehler - Jun 15 1993

Potassium perchlorate 70, Fimo [PVC "clay"] 20, Copper 10

It is apparent from looking at the formula that there would be difficulty with this formula but I tried to use it anyway. By the way, there is really no description from the source that says this a green star.

Even with warming the Fimo, it was an impossible task just to knead the 20 grams Fimo with the 10 grams of 400mesh Copper powder. But after mixing just a few grams of the KClO4 with the clay/copper, it became too crumbly to continue. Using clay, if it were feasible, would be too labor intensive in any event. Mixing powders is much easier than kneading powders into clay.

Hope the youngest generation of my family enjoy all the expensive clay I purchased.

..................................................................................

 

Green Star

 

Potassium nitrate 15, Sulfur 2, Airfloat charcoal 1, Copper powder 4, Red gum 1, Dextrin 1

 

Mixed with ethanol, substituting Phenolic resin for Red Gum, and the Copper was 400 mesh. They were cut and primed with Pinball. Will test if dry tomorrow.

[Niladmirari]

You know, yesterday I made a composition:

 

KClO4 - 40

BaCO3 - 20

MgAl - 20

PVC - 20

dextrin - 5

 

It was burning yellow flame What problems can be?

 

P.S.: KClO4 clean. I made it blue stars!

[schroedinger]

You should decrease the ammount of pvc you used is way to much. To cyte shimizu: 10-15 % can be used for magnesium based stars and less then 4% for other compositions.

 

From my experience mgal works best with about 8-10%. Also i would recommend the use of barium sulphate.

 

In al based comps 10% pvc is good too.

[hindsight]

schroedinger, It seems you are recommending a star composition with KClO4, BaSO4, MgAl, PVC(8-10%) and Dextrin. If you actually have a formula reflecting this, it is what I have been looking for. I would modify it for Phenolic resin and Ethanol binding.

[Carbon796]

http://www.skylighter.com/skylighter_info_pages/article.asp?Item=55#stick

 

Although, I'm not quite sure why your trying to avoid using barium nitrate. Which produces a better green IMHO and is more easily converted to using phenolic resin. The same precautions that you should already be taking when mixing other comps. Is all that is need when working with barium compounds. . .

[hindsight]

Carbon796, Yes, that is the formula for Radiant Green recommended by mabuse00 and psycho_1322 earlier in this thread. And as stated in response, I would use this if all other more soluble barium formulae failed. Sure, we use all the right PPE, but part of safety is avoiding exposures in the first place when practicable.

As it turns out, the Green Star formula from Post #23 was a waste (Potassium Nitrate 15, Sulfur 2, Airfloat charcoal 1, Copper powder 4, Red gum 1, Dextrin 1. Mixed with ethanol, substituting Phenolic resin for Red Gum, and the Copper was 400 mesh).
It ignited easily on the ground, but there was a two stage ignition in which the prime burned off and then the star lit. There was only a bit of green in the orange flame. When it was burned out there appeared to be tiny spherules of copper slag (despite sieving 2-3 times during the mixing of the powdered ingredients and kneading the comp patty thoroughly before cutting).

 

Unless schroedinger has a good green star formula ( see 2 posts above), Radiant Green or other Barium Carbonate recipe is what is left.

 

 

 

 

Edited for English

Edited July 26, 2014 by hindsight

[Carbon796]

It sounds like he is just making a general statement about the PVC percentage in the previous post. The PVC is probably also being used as a secondary fuel in that formula.

 

That kno3 / copper formula has been around for years, there is a reason why you don't hear of anyone using it. It may look better, if you got it hotter, but it will probably never be good.

 

If you want a "good" green, its probably not practical, but if your happy with an ok green, then maybe . . .

 

I would be more inclined to try the Charley Wilson version of the carbonate green. As listed on the skylighter website, if you decide to go that route.

Edited July 26, 2014 by Carbon796

[schroedinger]

Hindsigh5, no worries, i will have a look, but maybe can take a couple days as I'm not at home atm.

[Mumbles]

The whole quote, which comes from F.A.S.T. on page 150, is probably a little more telling. I bolded the important part that Schroedinger left out. The 4% recommendation may also be for chlorate stars, which also generates chlorine/HCl in the flame. I find organic perchlorate based stars need more chlorine donor, since it does not give up it's chlorine nearly as easily without some tricks.

 

"Polyvinyl chloride, therefore, is used quite favourably as an HCl gas producing agent to deepen the colour of flames. Too much however causes the generation of soot which decreases the light intensity and sometimes spoils the colour of the flame. Therefore 10~15% by weight % of the polyvinyl chloride for the compositions which contain magnesium and less than 4% by weight for other compositions may be the most adequate except when it is used as a fuel. Polyvinyl chloride contains carbon which allows the flame to become transparent by the reduction of the metal oxide particles in the flame,and is used also as a reducing agent."

 

Anyway, I use a generally similar formula to what Niladmirari posted, only it works. The biggest difference is the use of Parlon, and a blend of chlorine donor and other fuel to keep the soot down. PVC would probably work here as well.

 

Potassium Perchlorate - 35

Barium Carbonate - 25

MgAl (-200 mesh) - 14

Parlon - 13

Red Gum - 7

Dextrin - 5

 

(note: it's actually a commercial formula out of 24.75lbs, so this only adds to 99 in case it bothers you)

[a_bab]

Quick green stars sheet:

 

Ba based:

-nitrate: works best with Mg or MgAl. Gives good greens with Cl donor and metal fuel.

-chlorate: best green period, with organic fuel. No need for Cl donor. Burns slowly as such, and it is usually boosted with KClO3.

-chloride: impractical due to the hygroscopicity.

-sulfate: it preferably needs Mg to reduce it. Gives lots of smoke. Difficult to get the proper green and difficult to ignite.

-carbonate: only works with metal. Worst choice. The green is paler and it's difficult to get even an average green. Ba carbonate from pottery contains lots of impurities hence the usual issues.

 

Boron based: Expensive. Compositions are prone to spontaneous combustion it seems. Some people got badly burned working with B based compos. It also gives sensitive compos.

 

Copper based: Skylighter lists some. Not reliable as seen.

 

Zn: very nice green, more like a vert deep aqua. The resulted stars are very heavy since they typically contain >50% Zn. Excellent as cores for TT stars.

 

 

Ba toxicity: it is really unlikely you get poisoned unless you swallow your compositions. The usual route is mouth, and it is unlikely you'll ever get to this. There are many dangers much more serious than Ba toxicity when it comes to pyro. Just use gloves to avoid skin contact, a respirator and common sense. I've never heard of someone getting poisoned by Ba but there are plenty of stories about people getting seriously burned.

[hindsight]

 

 

Potassium Perchlorate - 35

 

Barium Carbonate - 25

 

MgAl (-200 mesh) - 14

 

Parlon - 13

 

Red Gum - 7

 

Dextrin - 5

 

Thanks, Mumbles. I will try it, substituting Phenolic Resin for Red Gum.

[pyrokid]

Mumbles, what was the commercial use of the carbonate green?

 

Consensus seems to be that carbonate gives inferior greens compared to nitrate, and the high MgAl and Parlon content of the carbonate stars seems to prevent any economic benefits of their use.

[Mumbles]

For organic stars, there is little doubt that carbonate is inferior. For metallic fuelled stars, that may not be the case. You'll find that most metallic stars based on barium nitrate will use similar amounts of MgAl and parlon anyway, so economics aren't really an issue. The general claim that nitrate is better than carbonate is because you can use the nitrate as an oxidizer, which allows for much higher barium content. The above formula allows barium carbonate to be utilized as an oxidizer as well. If you try it, I think you'll find yourself rethinking the notion that barium carbonate greens are universally bad. I don't think I have this particular green on video, but I do have the analogous red (1:1 replacement of SrCO3 for BaCO3).

 

Too many people get worked up over star formulas, and which one gives the absolute best color. The truth is if you can't build a good shell to begin with, the color saturation doesn't matter. A shitty shell with gorgeous stars is still a shitty shell.

[Differential]

I get a very nice green from copper borate, that I make by precipitating out of solutions of borax (sodium tetraborate) and copper sulfate. Should theoretically be blue, but there's a little bit of sodium impurity. The downsides are that it's poisonous and boron can be a flame retardant.

[Seymour]

There are green formulas using copper. In the right situation it definitely emits green, and boron is certainly a green colourant.

 

Is it really much more poisonous than any other copper salt?

 

What formulas have you got this burning green in?

 

I'm assuming you are not using a chlorine donor. I would personally be quite interested in a formula that had chlorine and copper and boron. I can imagine a nice turquoise could be obtained.

[schroedinger]

If you want to get a green out of copper you either need to use copper sulphate (pale) or copper powder and keep the temperature down. With copper powder its easy to get a blue effect because of the fornation of the chloride.

 

For a quite easy green star with god briliance and hugh light output just use barium sulphate and fine mg (1:1). But beware this has to be screened once through a 20 mesh screen and then wet mixed as it is basically a flash powder when dry. From this formula you can start a d tweak it down to your needs (the basic star makes a self prpelled star), by adding redgum and/or pvc to tweak the strengt. Add up to 15 % of pvc and up to 10 ^ redgum, but then you need a hot prime (maybe bp + 5-10% Si should work).