48 replies to this topic

[Richard H]

Indeed this might be the case. I tried it ad verbatim and the results were not too encouraging.

[Phoenix]

OK. I'm also quite interested in these hexamine based comps. Ofca's Fireworks Chemicals Reference Manual says that hexamine produces a yellow colour in some formulae, but he doesn't mention it as a colour or flame volume enhancer. However, he warns that mixing with chlorates can result in spontaneous ignition - ie don't do it.

I'll get some next time I get the opportunity, and give some nitrate based colours a try.

Edited by Phoenix, 28 March 2005 - 04:43 PM.

[aapua]

I decided to try this today. I prepared 10g of composition, weighing the components with a reasonably accurate (0.1g) set of pocket scales. I screened the chemicals together through a 60 mesh screen 3 times.

Got all excited as I placed the composition in a small pile on a test plate outside. Lit the length of blackmatch fuse and retired...Nothing

????????????????????????????????????
I tested it once again today, OK as the first time... Maybe this type of mixing is not enough? I put all the stuff together to coffemill and leave for few minutes. Sr-nitrate is from Merck, urotropine technical pure. NH4Cl from China.

[Richard H]

I will try again and see what happens. I don't think I plan on using a coffee grinder however.

[Richard H]

Just tried Strontium nitrate 85 Hexamine 15. Same problem again. My Hexamine appears very crystalline, perhaps the problem is insufficient mixing, even through a fine screen.

[alany]

Try it pressed into a tube with a little greenmix on top. If that doesn't get it burning nothing will. Even the most granular garbage mix will burn pressed into a tube if it has any possibility of doing so correctly mixed.

The comp does sound pretty suspect though, Ammonia and Nitrates?

[Richard H]

Put it this way. A small pile with a depression formed in the middle, with magnesium turnings and aluminium dust could not get it going.

[alany]

Who the heck uses sal ammoniac as a chlorine donor anymore?

[aapua]

Who the heck uses sal ammoniac as a chlorine donor anymore?

A bit ago I wrote about my experiments with different chlorine donors.

I started with base: 85 Sr or Ba(NO3)2 and 15 hexamine (known more as urotropine for me). Then I started to replace urotropine with smth else - dextrin, sulphur, Al etc. As a matter of visual colour, urotropine results were MUCH better than others. (Especially good is it with Sr, because SrO gives good red line in spectrum, but even green was clearly seen as green). The problem with urotropine appears, that it melts very easily, blocking the burning process. Adding a little of Al powder will increase brightness and burning speed, but doesn'd destroy the colour.

Then I started to add different chlorine donors. Sure, NH4ClO4 is the best. I do have it, say some 20 kg or so, but many of you here write it's difficult if not impossible to get it . Basicly seems PVC and parlon are used as donors. OK - what I noticed, was that flame turns yellow, the edge of the flame turns dark red. Note - just Sr(NO3)2 and hexamine give ALL THE FLAME IS RED. Not dark, but WITH NO YELLOW AT ALL.

And, NH4Cl was just one experiment. It darkened the colour, and the most important (at least for me): no yellow colour appeared. So, it was just the description of my small experiments, honestly I can't say why it's not gonna work in your hands. All 3 basic colours - red, green and blue - I made with same principe. Not as stars, just loose powder. The 1st idea was to see what fuel would be the best, and 2nd to find alternative chlorine donors.

About igniting the powders - I use usual match, so the actual igniter is open wood flame - one of the coldest flames.

Comment, taken from a russian patent. It says (for red colour): the most intense colour would be with SrCl2, Mg and urotropine. The exact mechanism of that fenomena is not known.

As for using nitrates and ammonia salts in the same mixture - I read your earlier comments. Just few days ago I tested a shell (2'' silynder), red peony, that was made 1,5 years ago. Seemed that all or at least very most of the stars ignited perfectly. I don't know exactly, maybe helps that sometimes (and for sure in this case) I use nitrocellulose as a binder. It should make stars more or less waterproof (humid-proof...).

Just comments.

Aapua

Edited by aapua, 28 March 2005 - 08:20 PM.

[alany]

There's a trick about using Carbon Monoxide to reduce Magnesium Oxide to Magnesium in the flame. Magnesium gas doesn't have the continium radiation fhat Magnesia does, so it clarifies the flame by removing that broadband black body light leaving the desired monochloride emitters as the major light emitting species.

Strontium Carbonate is normally used because it liberates Carbon Monoxide on decomposition. In a SrCl/Mg/Hexamine composition there is no Oxygen, so no Magnesia production would occur in the flame. Will it actuall work? Not sure, XCl/Mg mixtures will burn, usually quite brightly and coloured if X is chosen correctly. Such compositions usually aren't very practical though, most colour donors are similar or more powerful reducers than Mg. Works with Copper though.

[aapua]

Well, if anybody is interested, here I post the results of my small experiments.
All the compositions are made like: Sr(NO3)2 or Ba(NO3)2 83%, hexamine 12% and X 5%. X is NH4Cl, PVC or C2Cl6. In order to better understanding - these compositioms are not meant to be ignited as stars copositions.
For sort of my dissapointment, seems that the type of urotropine plays great role in the process. So, if compared to my earlier experiments, this time I got some differences. This time C2Cl6 gave very nice result - note that although the flame itself is mostly yellow, the bursts are very dark and clean colours. And PVC acted not bad as well. Anyway, you look and decide yourself.
Just one more note. It is much more pure and nice in the nature, video is just the pale shadow of that...

The address is:
http://www.hot.ee/aapua1/flares

Edited by aapua, 06 April 2005 - 09:00 PM.

[Yugen-biki]

Very interesting!

PVC seems to be the best Cl-donor, and it has the advantage of being a fuel at the same time. Makeing it a bit more easy to ignite and keeps the flame vibrant/strong.

Readers of Skylighters? newsletter about blue stars find that the ones containing hexamine are hard to ignite. And because of that ranked lower than others. This might be a problem for other stars as well, the ignintion problems that is. They'll probably need a heavy prime to be practually useable as stars.
But the colors are good, no doughts about it!

[KABOOMIE_SITH]

hi well i am an amatur enthusiast, i have a query though, i can really only use shop bought chlorate, i tested said chlorate with aluminium, to discover the wonderfull world of sound and light enhanced by several thousand metres per second. I wish seriousley to byuild a high energy rocket that isn't briscant, i tried grinding in charcole but the mix burns so slow as to be of no use. I realise sensitisers can make it burn faster, such as phosphorus and sulpher but what percentage am i looking at for a resonable burn for a rocket tube as i wish to push my saturn 5 replica too dizzyheights rather than blow it to bits or get a damp squib. The other curious question zirconyl oxide di perchlorate, this must produce some peritty decnet thrust as ziconium boils at about 5,000 c but is there any legal hassles anyone knows of ?

theorectecally this should work if you follow my thinking

ClONa +H2O + NAF -----warm to boiling then simmer-----NAFO3

sodium flourate should be the end product, that will give you a superior propellent if mixed in with a hydrocarbon or alluminium as the Hydrogen flourine reaction is very energetic. Without wishing to break a rule this would have to be prepared from home as nowhere i have seen sells it ! I have a degree, i spend all day working out this stuff for fun . Ideally because of the florine being also a halogen and stronger than chlorine it should have a greater affinity for the oxygen than chlorine...i dont think the chlorine will displace flourine, but as all theories go i could be wrong. Saying that they are in the same period and florine is going down the period so must be more reactive. It will also give a bigger bang in salutes, knallkorpers etc. But it may also be more friction sensative...it may give up to 25% extra energy .

Edited by KABOOMIE_SITH, 11 April 2005 - 07:39 PM.

[paul]

Never heard of that stuff. Sodium flourate.

ClONa +H2O + NAF -----warm to boiling then simmer-----NAFO3

seems not to work.... Where?s the Cl gone?! Its not balanced correctly I think.

What do you think about it?

[Stuart]

Sodium Fluorate could never exist, Fluorine's only oxidation state is -1, unlike Chlorine which can go all the way to 7+. What exactly are you trying to do, make a big nozzle less rocket or a normal rocket to be sent a few kilometers in the air?

Edited by Stuart, 11 April 2005 - 08:59 PM.