Hi all,

I have been searching in this forum for the last posta about colored flashes. I made during the past weeks some research on it and I would like to compare opinions with people who really tested compositions of this type.:confused:

I found the following rules regarding colored flash (when I say "flash" I mean a composition that confined will "bang" same as 70:30 standard flash)

1.- Magnesium particle size has some relevance in this formula. Fine material can make a good report with Sr(NO3)2 but good color it seems can be obtained with corase magnesium. I tried in my formulas the finest magnesium. mf-70 (maybe 0-50 microns)
2.- SrCo3 makes a FANTASTIC color along with magnesium, but a "puff" effect.
3.- Sr(NO3)2 makes an acceptable "bang", but with a pale red.
4.- I am not sure about if Al added, helps the "bang"
5.- Adding Chlorine donor (in my case 5%) improves the color. I have noticed that some people prefer PVC for flash compositions or Saran, better than Parlon. In my case I tried only Parlon and defenetelli imnproves the color but slightly reduces the "bang" effect.
6.- I add some KLCO4, not sure about the improvement in the "bang"

The formula I tried is kclo4 14/Mg 45/SrCO3 30/Parlon 5/Black Al 6

Wait ur coments

Eliminate the Al, the white Aluminum oxide destroys color with white light. Increase the chlorine donor to 10%, or consider using fine Teflon powder to replace some of the oxyhalide oxidizer. Chlorate is prefferable from a standpoint of additional chlorine content, but I'd rather use nitrates and perchlorates from the standpoint of safety.
Strontium carbonate is a good star collorant, but will drastically weaken flash performance as you have noted.

The mixture at the end of your post is very Oxygen deficient, to the point that I am surprised it would burn.

In all cases, Mg based colored flashes that perform acceptably as salute powders are so bright that they must be viewed at very long distances for the true depth of the color produced to be apparent- The high light output at close range will wash out the color.

...The mixture at the end of your post is very Oxygen deficient, to the point that I am surprised it would burn....


I try to post a video, so u will be more surprised. The bang is more than expectable... Adding Parlon will increase color but will reduce the speed of the composition. That is why maybe the "trick" is on a different chlorine donor...

I experimented with some attempts at blue flash powder a few years ago, with no real positive result. I think I got it to burn blue, but I used so little aluminum that it didn't flash. If I recall correctly I used CuSO4, sucrose, powdered PVC, a tiny amount of Al and KClO4. Zero clue about the ratios I used.

Edit: I may have used CuCl2 instead of the sulfate I am really not sure, I should have kept better records.

Blue flash powder is not likely to be workable. Copper stops being a blue collorant and starts burning green at around 1400 C. Good blues are generally organic fueled as metal fuels will overdrive them and lose the blue color-

You should not use CuSO4 in pyrotechnic mixes. Between the reactiviy and the large ammount of water of crystalization, it's a poor choice, and a dangerous one with chlorates.

I think for these types of compositions, the best chlorine donor should be Saran; at least in terms of not lowering the performance of the combustion... I was reviewing some publications from Dr. Kosankes and by chance I found a brief comunication about Saran resine in which he states "With properly adjusted formulations, Saran resin was found to equal or surpass PVC and Parlon with respect to ease pf ignition, size of flame envelope,a dn resistance to being extinguished (blown blind).... He conducted the test using Saran along with KCLO4...Need to try the difference in a colored flash composition...

In pyrotechnics they use for blue: CuCl, CuO, CuO2.

Copper carbonate, Copper oxychloride and Copper aceto-arsenite have also been popular. Basicaly, any reasonably cheap and non water soluble Copper compound. Copper benzoate is getting popular as well, even though it is soluble. Copper metal powder has been used, but there tend to be problems due to the metals's reactivity. Fused Copper sulfide is easy to make yourself, and works well also- Best you don't use it with chlorate, however.

Gomis, I find your post excellent, even though this is my second time reading it. I think you may be on to something with the "under oxidizing". If you recall Degn's Colored Flashes are heavily oxidized and all perform rather poorly for color and well for salute. Why didn't you post the video you posted on APC? Here is the link to his video:http://www.apcforum.net/forums/index.php?act=Attach&type=post&id=16303. If your first flash is indeed the formula you posted it is probably going to be seen more often in the next few years.

Knowledgehungry: Paris green (Copper(II) acetoarsenate) is supposed to be a good colorant for blue flash, unfortunatley I haven't been able to try it. In theory I would use something like hexamine over sucrose as it is known to have an overpowering orange flame. But ratio's are missing and they do have a bit to do with these kinds of things. I have never used copper chloride, but I can see it being very useful.

I am going to try the final formula you posted. As well as substituting Barium Carbonate for the Strontium Carbonate to see if it performs as well.

Evilblaze: Next time think before you post. It is in my opinion best to assume readers know common knowledge of pyro and/or chemistry when posting to help keep the forum clean and the text worth reading.

UPDATE: I was not aware that any authentication was required to download from that site. Regardless here is the Rapidshare file location: http://rapidshare.com/files/18488411/red_flash_test.mpg.html

The video can't be downloaded unless you are a member of that board.

Either provide a Username/Password, or an alternate source like rapidshare. ;)

Gomis, the first of the three red flash/reports was very nice indeed!

Having tried several times with less than spectacular results, I found that it's not as easy as it looks to get an acceptable color depth, at least using Degn's green and purple formulas.

I think much of the problem lies in my having used magnalium in place of Mg.

For those of you who haven't seen this there are some excellent colored Flash recipes here>http://www.privatedata.com/byb/pyro/pfp/flash.html

Regarding the Oxygen balance of the first mix posted by Gomis- The carbonate will decompose to produce CO₂. The CO₂ can then oxidize Mg, which burns fairly well in it. But both of these processes drain a lot of energy from the flame, relative to more commonly used pyrotechnic oxidizers which produce free O₂ and require less energy to decompose than a metallic carbonate-

You might want to try using Teflon powder as a dual purpose oxidizer/halogen donor along with Sr(NO₃)₂ as a dual purpose Oxidizer/colorant in such proportions to bring the Sr content to approx. 8% of the total mix, with Mg as a primary fuel and only enough low temperature fuel such as Sulfur or organics as needed to ease ignition. For color production, it is best if the mix is SLIGHTLY O₂ deficient-

I agree with you Bert. It seems that in this type of compositions to be O2 deficient is good for color saturation. I have tried many times and proportions using Sr(NO3)2 as color agent/oxidizer and never such a good color as that one achieved with SrCO3. Furthermore, a Degn type formula, mixing both Strontium salts, will not work. What's worse: the results are much more whiter flashes than those using only Sr(NO3)2 and Mg in a 50%-50% ratio !!

I think boosting the oxidizer through KCLO4 or even KClO4+Barium Nitrate can make a more fast burning, keeping the color saturation. Did not try...maybe this week.

Don't add Barium. The mix of Barium and Strontium produces an indeterminate, muddy color.

This may be unworkable, but I am going to give it a shot anyways. I was thinking maybe adding metal salts to a KClO4/Al mixture will add some color to the flash as the reaction of the flash composition will burn the metal salts. I may be completely wrong on this, but I do have the opprotunity to try this out come Monday unless someone tells me it isn't worth the effort. No one had anything that I could find using the dearch engine, but I am still a little green in these matters. Any advice or words of wisdom will be welcome.

Also, normally I would post this in the water cooler, but it seems to be down, so please don't come down too hard on me if it doesn't seem like I know what I am talking about.

You will have better results by using Mg instead of Al in color flash comps.

A good red flash comp is:
KClO4 15
Mg 50
SrCO3 35

For a louder report with color, add ~10% more KClO4 and remove ~ 10% SrCO3.

Mg should be fine. Works well with KClO3, also.

Blue flash (blue in general) is a difficult color to achieve with any degree of clarity. One reason is that metals like Al & Mg typically drown out blue with white from the burning metal. Some time back PGII members were experimenting with brass powder which many claimed was worth a try. It needed to be somewhat course (key shavings?).

A ball mill with steel bearings would drive brass to small flake configuration relatively easily. I have tried (while making stars) copper powder, barium nitrate (& carbonate), etc, etc and came very close but it was too dark to carry at night. Brass may be a good compromise.

By all means give it a try, there is no substitute for experimentation.

Generally, for color production Mg is a far superior fuel to Al, and Mg/Al alloys are the second best. Al₂O₃ in a flame is a solid dust, and produces white light (a solid heated to incandescense produces black body radiation of mixed wavelengths). This washes out any color, you want only GASSES inside your flame envelope, with the desired color producing species being the mono chlorides of Barium, Strontium or Copper. MgCl₂ formed from extra Chlorine donor in a slightly Oxygen deficient environment is FAR lower boiling than Al₂O₃. MgCl₂ will be a transparent gas inside the flame envelope- That's why good quality metal fueled colors are known as "Mag colors" not "Aluminum colors", and why you keep hearing references to "chlorine donors" as part of a color mix.

.............Melts........Boils

Al₂O₃... 2,054 C... 3,000 + C

MgCl₂... 714 C..... 1,412 C




(edit)

Summer is here, and the pyro forum jumps to life...

Anyone who is going to be at the PGII convention some of the days between Sunday and Wednesday and who wants a display credit towards their display operator's credentials, you may contact me. I may have work for you.
If you are in the twin cities area, I have other learning opportunities as well. Must be 18, no felonies.

Thank you for the words of wisdom Bert, and it happened pretty much as you said. Either the ratio I was using wasn't right, or it simply won't work at all, but all of the trials I did had the aluminum wash out any of the colors that could have been produced by the metal salts (there was a little bit of blue around the edges when I used copper chloride which gave me a little hope, but after more experimentation I realized that was from the aluminum). After reading your reply I really want to try it with magnesium, and make the fuel a mix of 1:1 Mg to a metal salt such as strontium chloride or copper chloridefor the desired color. Unfortunately I have just graduated :rolleyes: and no longer have access to my highschools lab facilities and supplies. Some friends and I might order some chemicals for the soon upcoming fourth, but if that doesn't happen then I won't be able to test this until college :o .
Also, if you coud email or pm me some more information about this PGII convention, I would definately be interested. Only issue is where and when and whether I could get transportation for it. Always looking for more learning opprotunities.

Here is a formula for a Red flash composition that I think is good:

Magnesium, atomized, 100-325 mesh 10
Strontium Carbonate 7.5
PVC 1.6
Potassium Chlorate 1.4

And why do you think it's good?

Did you make it, burn it, and like the color?

Or did you copy it off a website somewhere?

I doubt he tried it, unless he transposed the parts of chlorate and carbonate. And even then it would be fuel rich.

With ~50% MG and only~7% KClO3, it probably will not ignite, let alone be "good".

If anyone wants to try a good, proven red flash formula, here's one:

Pyro-Tec Red Flash
Mg, fine 50
Strontium carbonate 38
Potassium chlorate 12

Hi all

I tried this Formula long time ago:

50% CaCO3
40% Mg-powder( homemade, fine as flour)
10 KNO3

Produced a very blinding flash and when confined a good bang.

I caught some flash on tape.

Here you go:

http://youtube.com/watch?v=NLJw_tXbJ5E

And here is a salute with 1,0g in it:

http://youtube.com/watch?v=_A3kYd7EKrA

Rainbow Salute Compositions:

Blue: 20 Parts Magnesium Powder (100 mesh or finer)
20 Parts Potassium Perclorate
6 Parts Paris Green
1 Part PVC

Green: 10 Parts Magnesium Powder (100 mesh or finer)
10 Parts Barium Nitrate
1 Part PVC

Purple: 10 Parts Magnesium Powder
10 Parts Potassium Perclorate
3 Parts Cupric Oxide
3 Parts Strontium Nitrate
1 Part PVC

Red: 1 Part Magnesium Powder (100 mesh or finer)
1 Part Strontium Nitrate

White: 1 Part Magnesium Powder (100 mesh or finer)
1 Part Potassium Perchlorate

Yellow: 1 Part Magnesium Powder (100 mesh or finer)
1 Part Sodium Oxalate
1 Part Potassium Perchlorate

These were taken from the Westech Fireworks Manual.