Color producing agent purity

[AdmiralDonSnider]

Hello to the APC community! Nice to finally be here.

 

 

I wondered if impurities contained in color producing agents like SrCO3, BaCO3, CuCO3, CuO etc. have a noticable effect on color quality?

 

I´m asking this because I use pottery grade carbonates and oxides for making stars. As I´ve never bought ultra-pure counterparts to make a comparision, I would be interested if somebody has some valuable information about this topic. Thanks for any help.

[Steps]

Iv used pottery grade chemicals on all of those things except the Copper Carbonate. I have honestly had no problems with them mind you i have not tried any other grades except for the Copper oxide.

 

Never seemed to have a problem with the Barium and Strontium Carbonate.

 

The Copper oxide that I got from the pottery was better than the other stuff (some idiot i know of bought from the US) when it was used in copper thermite for shell boosters.

 

When i am making the strontium and barium into nitrates they seem to evolve a lot of Hydrogen Sulfide. So be careful with compositions containing chlorates.

[al93535]

Most of the pottery chemicals are very useful. It just depends on how picky you are on color purity. You can use all the coloring agents you want from there with good results. However I must say, red lead from pottery suppliers, (at least mine) Didn't work for shit for dragon eggs.

 

Its cheap and works, use it!

 

If you are in advanced stages of pyro, or making competition grade pyro, then by all means get the best you can.

 

Its like buying tools or a saw, the cheaper ones get you by just fine..... but you do get what you pay for.

[Swede]

$$ is the problem. ACS reagent-grade metallic salts from some place like Sigma Aldrich are going to cost $150 for 250 grams, whereas the pottery stuff is $8 for 5 pounds. If the pottery stuff gives 95% of the color of the reagent-grade, I'd consider it money well-saved.

 

Sometimes you might stumble onto the pure stuff for cheap, but it is rarely a continuous supply; more often just a lucky deal.

[Mumbles]

Thats because Sigma has a huge markup. Pretty much anyone actually ordering from Sigma has a big discount. There are places to get said high purity metal salts in larger quantities at a fraction of the cost. I have no idea about ordering requirements/licences/minimum sizes/etc. This company supplies some of the best products I've ever used.

 

http://www.bariumchemicals.com/

[a_bab]

Fuck the ctrl + W key combination!

 

Anyway, I was writing that at some point I've got few kgs of reagent grade SrCl2. The plan was to convert it into the carboonate salt. Not having anything at hand but the OTC obtained NaCO3, and after studying lots of MSDS sheets, it turned out that the table salt could be more toxic than SrCl2. So I went for the "home bathtub synthesis" and this was an adventure of its own (3 days of messy bathroom, a week of white spots on all the objects in the bathroom, a mad wife etc.). Not that I'd do this with the BaCl2 I have...

 

It took lots of washings (some 6-7 of 'em) to get the Na out (checked with silver nitrate). In order to have the washing water totally escaped thru the filter (a cloth), I had to wait for hours. The drying of the Sr carbonate took many days too.

 

Anyway, after testing the SrCO3 with my KClO3 system (along with sugar and a bit of hexamine) it turned out it was quite good. It looked as good as a non metalic fueled star with no chlorine donor can look.

 

I'd suspect that it's not going to work the same way for Ba, and especially copper due to the inherent traces of Na.

 

 

On this subject, has anyone tried to precipitate an insoluble copper salt with a sodium salt for a use in pyro?

 

I recall something Mumbles may have said about black copper oxide out of heated copper hidroxide (precipitated from CuSO4 and NaOH), and having concluded that KOH would have been a much better option.

[AdmiralDonSnider]

Thanks so far. (Nevertheless I´d like to hear some more opinions.)

 

What made me doubt that I´m currently using good stuff are some videos posted here in the forum as well as some on youtube. I make a lot of can shells using chlorates and modified organic formulas (good chlorate formulas seem to be rare) where I replace the perchlorate 1:1 with chlorate e.g. Shimizu´s Organic Blue #2 from FAST (using CuO). Comparing my results with the ones shown here (or there: http://www.youtube.com/watch?v=DxrL2OOYVaM...;feature=email) in the videos, I get the impression that my colors come out weaker. So maybe I´m using impure copper oxide.

 

I would be quite content with pottery grade chems if I knew they give 95% color performance...

 

However, it may also come from the replacement of KClO4 with the chlorate, if the formula would need adjustments I don´t consider in absence of knowledge. (Is there a rule of thumb how to modify perc formulas when using chlorates?)

 

Furthermore, do you think CuCO3 would give better colors than CuO?

 

On the other hand, maybe these differences are pure imagination. I hope so.

Edited March 19, 2009 by AdmiralDonSnider

[a_bab]

CuCO3 doesn't give better color than CuO because it decomposes in the flame in CuO and the useless CO2; besides it does this with the cost of lots of energy. So basically it's like using "diluted" CuO.

 

It's good for making the far more superior copper benzoate I'm after.

 

A good theory of using the chlorates to get colors can be found in "the blues" articles (1, 2 and 3) from the skylighter newsletters. Potassium chlorate is superior in getting the right colors compared to perchlorate (it releases chlorine in flame) but it still needs extra chlorine. In the past they used mercuric chloride that made chlorine and mercury in the flame. There are no other non-poisonous salts that are able to do this, hence the use of the "organic based" clorine.

Edited March 19, 2009 by a_bab

[AdmiralDonSnider]

A good theory of using the chlorates to get colors can be found in "the blues" articles (1, 2 and 3) from the skylighter newsletters. Potassium chlorate is superior in getting the right colors compared to perchlorate (it releases chlorine in flame) but it still needs extra chlorine.

 

Yeah, I read quite a lot of formulas that use calomel. However, I think I read the right articles but I couldn´t find useful information on how to best modify perc formulas when using chlorate. Could you go into further detail?

[Mumbles]

In some of the more current perchlorate based formulas, sulfur is used in combination with the perc. It causes the pechlorate to give up chlorine just like it's slightly less oxidized counterpart. I still wouldn't be caught dead without an additional donor though, my favorite is saran.

 

For colorants, I find CuCO3 to give the least intense colors. My personal formulas all use CuO, though I have yet to experiment much with Copper Oxychloride or Benzoate. CuO has a tendancy to get the red edges more than the CuCO3, perhaps due to the flame cooling already mentioned.

 

Yes, I tried to prepare CuO from Copper sulfate and NaOH. Total pain in the ass. The sodium sulfate is very hard to wash out. I would always get those damn white crystals blooming from the brown CuO. As it turns out, if you do the reaction on a 5 gallon scale by adding NaOH to CuSO4 solution, it generates enough heat to convert the Copper Hydroxide to Copper oxide on it's own. I was able to wash it out on a small scale, an ounce or so, by using a vacuum filtration device, and washing with boiling water a few times. I think it would have worked on the large scale, if I let the solid dry out more between washings, and used warmer water.

 

I have very little experience with Chlorate formulas. I gave the chlorate blue I use to you on UK Pyro Society. Thats one of the few chlorate formulas I've made, and pretty much the only I was pleased with. The others didn't have as nice of colors. Though I was comparing metallic perchlorate formulas to organic chlorates. I have a very nice set of perchlorate based formulas that have intense saturated colors, so I have no real need to use chlorates.

[AdmiralDonSnider]

I looked through the star comps thread on UKPS but I can´t find your formula. Could you share it?

[Mumbles]

It was in a thread about chlorate colors I think.

 

From Dave Stoddard on PML:

 

In keeping with the practice of remaining on topic for posts,

this is my favorite blue star comp (it is my modification of

a formula originally posted by Shimizu in FAST):

 

Blue Star

 

Potassium Chlorate ........ 64.5 %

Red Gum ................... 9.9

Cupric Oxide .............. 13.4

Parlon .................... 5.4

Charcoal .................. 2.0

SGRS (Binder) ............. 4.8

 

Lights easily, burns fast, good blue color.

[AdmiralDonSnider]

Thanks for sharing. This is Shimizu´s Blue Star #2 with 2% charcoal instead of the oxidizer and using KClO3 instead of perc. However, does the addition of charcoal really add to the color? Did you ever make a side by side comparision?

[Mumbles]

Nope, only tried the chlorate one, it's said to give a very nice color, and I agree. The charcoal is to smooth the burn, and perhaps eat up extra oxygen to prevent the red edges.