60 replies to this topic

[zanes]

Hello, for a while I've been pondering about green colours- more specifically for rocket exhausts and possibly stars (?)

While I was making charcoal on an ancient primus stove, my mind wandered onto colours- and then i remember being told by my junior school chem teacher that certain elements compound burn with different colours- take copper for example(and the fact it's easy to get salts AND I have a large tub of CuSO4 in my chem chest )

Anyway, I scooped a bit of CuSO4- yes it is pure- no H20 (its anhydryous ) onto a nail and placed it into the flame- nothing for a sec, and then the flame was coloured a BEAUTIFUL green.

My question is: can i add CuSO4 into my rocket comp to make the flame burn green, or for that matter can I add some to lamo bp to make coloured stars? I understand about the REALLY complex formulas for green (funnily enough I DON'T have 1 kg of barium nitrate or KCL04 lying around- although I do have a bit of mg powder i foung in my chem chest.)

Cheers for listening to my endless newbie prattle-

Alex

[Arthur Brown]

Copper sulphate is hygroscopic so it absorbs moisture from the air. some compounds start to self heat and self ignite when wet read up about this on several sites before you play. Remember the device you make must be stable til you want to fire it.

[BigG]

Hello, for a while I've been pondering about green colours- more specifically for rocket exhausts and possibly stars (?)

While I was making charcoal on an ancient primus stove, my mind wandered onto colours- and then i remember being told by my junior school chem teacher that certain elements compound burn with different colours- take copper for example(and the fact it's easy to get salts AND I have a large tub of CuSO4 in my chem chest )

Anyway, I scooped a bit of CuSO4- yes it is pure- no H20 (its anhydryous ) onto a nail and placed it into the flame- nothing for a sec, and then the flame was coloured a BEAUTIFUL green.

My question is: can i add CuSO4 into my rocket comp to make the flame burn green, or for that matter can I add some to lamo bp to make coloured stars? I understand about the REALLY complex formulas for green (funnily enough I DON'T have 1 kg of barium nitrate or KCL04 lying around- although I do have a bit of mg powder i foung in my chem chest.)

Cheers for listening to my endless newbie prattle-

Alex

Copper salts are used mainly for BLUE colour, although you do find then in some green compositions. Copper carbonate can be used for blue and make good blue together with parchlorates and chloride donor. Copper oxychloride makes great blue and is also a chlorine donor. Copper Chloride is used in some formulations for blue and purple - but being corrosive and more expensive then the alternatives - is not used often.

You cannot just add Copper to your BP rocket and get blue colour. The flame temperature is not high enough. While in charcoal fire or over a direct flame using a metal to hold copper chloride - temperature might reach high enough (around 1600+) to generate colour. However, your BP compositions don't pass 1000 degree C, and therefore will not generate colour. Together with magnesium you will get there, but the colour will be "washed" due to the smoke that burned magnesium generate.

BigG

[zanes]

Really?

I thought BP would get TOO hot for colour

Can someone please post SIMPLE colour formulas (in the newbie section?)

[BigG]

It's not BP but Nitrates in general. They are not energetic enough... Look under "red stars" thread for a basic red color formula that Richard posted.

BigG

[zanes]

so you're saying that nitrates don't realese enough O2 for v. hot fires?

[BigG]

so you're saying that nitrates don't realese enough O2 for v. hot fires?

It's one of the factors. Nitrates release only 1/3 of their oxygen compare to chlorate and parchlorate that give it all away. It also has to do with what energy you need to put into the chemical to release the oxygen, the fuel, ETC. Barium and Lead nitrate allow hotter flames then Potassium Nitrate. With barium you can cross to the 1000-1200C region, which is still not enough for colour. With Magnesium, you can reach 1800+, which allow you "cold-temperature colours".

This is also the reason why Chlorates are still being used. Some brilliant colours cannot be reached without chlorate-enabled temperature (together with the fact that they are the cheapest oxidizer).

BigG

[PanMaster]

i thought chlorates were ultra low temp oxidisers? < 300c

[Richard H]

i thought chlorates were ultra low temp oxidisers? < 300c

Nope, why do you think nitrates dont work well in colour compositions? Chlorates are much more powerfull oxidising agents then nitrates.

[Jerronimo]

A formulation I use for blue stars:

KCIO3 50%
coppersulfate 25%
sugar 25%

This gives a lightblue color.

[Pyromaster2003]

couldthe copper sulphate be substituted for copper oxide?

[zanes]

A formulation I use for blue stars:

KCIO3 50%
coppersulfate 25%
sugar 25%

This gives a lightblue color.

I love you! My garage loves you! My Neighbours hate you! My car loves you!

Eh? maybe my car doesn't love you, I wouldn't know

[Jerronimo]

HAhaha what about your garage has that a mind of it's own then?

What kind of binder did you use?dextrin?

Oh by the way,
You may have to fiddle with the percentages to get a optimal burnrate.

Red star:

KCIO3 55%
strontiumcarbonate 25%
sugar 20%

Ha, don't you just love sugar.

Edited by Jerronimo, 28 October 2003 - 07:56 PM.

[BigG]

Okay here we go again?

It is obvious that many of our members do not understand anything about chlorates ? and it would be wise for them to step away from such formulas until they do. A recommended title will be "working with chlorates" by Bill Ofca.

Now, Zenes, I assume that you use BP to fire your stars. If that the case, you will be calling upon an accident rather quickly, as Chlorate/Sulphur mixture are very sensitive. You should also not mix chlorates with a verity of items, and should have completely different work surfaces/tools and storage areas for chlorates.

I stress no beginners should attempt his first colours with chlorates. The replacement of chlorates with parchlorates in recent years is down to the many accidents that chlorates are responsible for.

For those who provide chlorate based compositions on this site ? please do so with proper instructions.

BigG

[zanes]

Actually, I haven't got any KCLO3, I just appreciated the idea. I know about chlorates and sulphur.