A deep question

[Arw]

why PVC and parlon use in stars?

what's this mechanism?

both of them have Cl

[Mumbles]

Chlorine improves certain colors by producing different species in the flame.

[Arw]

Chlorine improves certain colors by producing different species in the flame.

an example please

[Mumbles]

BaCl.

[Arw]

so why we don't use BaCl instead BaNO3,since we use KClO4 as oxidizer.

[Arthur]

In a dry formula, which has to be stable for years, we cannot use compounds which have unwanted reactions. For example; Strontium adds red colours to flames but we usually don't use strontium nitrate because it attracts water from the air and is then too wet to burn, so we have to use strontium carbonate because it's stable in use, even though adding the carbonate can reduce the burn rate.

 

MOST colour producing components work better when chlorine is present, Chlorine comes from chlorates and chloro organic compounds (PVC Parlon etc) each of which can have slightly different results for reasons including the proportion of chlorine atoms in the molecule.

The exception is sodium, It's yellow colour doesn't need a chlorine donor.

[flying fish]

Barium Chloride (aka barium dichloride) is BaCl2 - that's solid and stable at room temperature, but that's not what Mumbles is talking about. Barium monochloride is BaCl, and that must be produced in the flame for a green color. Not being a chemist, I can't tell you what the reaction mechanisms are, but I think that's the simplest explanation. Perhaps Mumbles will elaborate if he comes back to this thread.

 

As far as greens go, there are some compositions that use Barium carbonate, but I don't think they are very good. The best bright ones use Ba(NO3)2, MgAl, and KCLO4, where as the best dim ones use Ba(ClO3)2 and any number of organic fuels such as red gum or shellac. Barium Chlorate formulas are extremely sensitive though, so I don't recommend their use.

[Arw]

OK.

i got it.

tnx

[juicesdad]

Sorry to change the question but I need a smoke bomb with color and a little boom on the end. Any ideas?

[OldMarine]

Be prepared to pay out the wazoo for smoke dye and don't try a boom. You'll get a boom with a bunch of wasted dye unless you press a clay bulkhead in between the smoke and BP "bump" with a small passfire hole in it. The smoke comp gets so hot it'll set off your thump before it's even burned down to it. I gave up on mixing the 2 since it was pretty anticlimactic anyway. I prefer to set off my smoke in the background with some strobe pots firing behind it and then light off some Ti fountains at either end to really light the colored smoke. I put my bounce charges in my gerbs to finish off the whole shebang.

[Arthur]

Colour is generated when photons are released from metastable flame products (a flame is a high energy reaction space where almost anything can exist for short times) as they energetically collapse to stable cold entities.

 

Currently it's suggested that the colour generating species are the metal monchloride radicals in high temperature states and that some of their cool down energy is released as photons of assorted but very specific energies hence colours. Remember that a flame is typically at 2000K to 5000K so almost anything can happen instantaneously. Also electronic energy transitions inside an atom, ion or radical are quantised so the energy (hence colour) will be seen as specific spectral bands. By varying the environment of a flame some element's "colour" can be changed by the presence or absence of other supporting reactants by the varying amounts of excitation of their many spectral lines -compounding matters! Hence the reason that Barium causes various shades of green according to the fuel used and other compounding choices.

 

Many flame colourant metals have a wide spectrum of emission lines which can be selected by the flame environment. Sodium has so nearly ONE line (actually a doublet) that A/ sodium needs no chlorine in the flame and B/ nothing will change the apparent colour of the flame.

[Arw]

Colour is generated when photons are released from metastable flame products (a flame is a high energy reaction space where almost anything can exist for short times) as they energetically collapse to stable cold entities.

 

Currently it's suggested that the colour generating species are the metal monchloride radicals in high temperature states and that some of their cool down energy is released as photons of assorted but very specific energies hence colours. Remember that a flame is typically at 2000K to 5000K so almost anything can happen instantaneously. Also electronic energy transitions inside an atom, ion or radical are quantised so the energy (hence colour) will be seen as specific spectral bands. By varying the environment of a flame some element's "colour" can be changed by the presence or absence of other supporting reactants by the varying amounts of excitation of their many spectral lines -compounding matters! Hence the reason that Barium causes various shades of green according to the fuel used and other compounding choices.

 

Many flame colourant metals have a wide spectrum of emission lines which can be selected by the flame environment. Sodium has so nearly ONE line (actually a doublet) that A/ sodium needs no chlorine in the flame and B/ nothing will change the apparent colour of the flame.

so is that true,blue since of highest frequency and highest energy need more temperature and is hard to obtain and red is easy?

[Arthur]

Using copper for blues you can get all shades of blue and no blue! Copper has lots of spectral lines and you have to do the compounding well to favour the lines at the blue end of the spectrum.

 

There is a powder sold for colouring bonfire flames, it's based on copper salts but it gives lots of colours in the blue and green region of the spectrum, it's compounded for colours, not just blues.

[Mumbles]

Blue is the hardest color to obtain and red is generally the easiest, but not for the reasons you mentioned. Red is easy due to the emitting species present in the flame. The preferred one is SrCl (as is strontium (I) chloride), which burns a vibrant bright red. The other species present in poorly balanced or optimized formulas however also generally burn red. SrOH particularly is more of an orange-red, but still unmistakably reddish.

 

Blue on the other hand is hard because it requires the lowest temperatures actually. The magntitude of energy in visible light is actually not very significant relative to the amount of energy present in a star. The ideal blue emitter, CuCl, is unstable at higher temperatures, so the flame temperature must be kept in check. It also happens to be relatively weak, and the human eye response is poor in the blue. This often means that contaminants or other emitting species can easily overpower the desired color. Additionally other emitting species tend to produce light which is not even remotely blue (often green, orange and red), and can cover up the blues. If you watch blue stars up close you will often notice green and red tips and edges around the flame envelope due to atmospheric oxygen interacting with copper ions and radicals.

[Arthur]

Blue stars may well be compounded to make gas as gas carries heat away and the flame centre will remain cooler, promoting the blue spectral lines. Good compounding gives lots of chloro species in the flame (ions and radicals) at a moderate temperature. Anything that promotes OH species in the flame will promote unblue colours destroying the star colour.