Al Koholic - 19-1-2004 at 07:14
A few weeks ago I machined a nice double-boiler pot to heat wax for making candles in. Inevitably I got to thinking..."Hey, what if I could mix
some organic copper salts into this wax to create colored flames?"
My idea basically revolves around creating a copper salt of say, octanoic acid or some other long chain aliphatic carboxylic acid. These salts, if
they can be made, should dissolve nicely in the molten wax due to their long chains. I was also considering copper II acetate but that might be ionic
enough to not dissolve.
Actually, now that I look in CRC, I found that copper oleate and copper sterate are listed as soluble in ether and alcohol. Good news so far! Were
these compounds to be included in a molten wax mixture of proportion to be determined, I should be able to make candles that burn with a nice blue
flame!! :-)
Also, if I didnt want to go with such a long chain, I could cleave the double bond in the oleate chain to yeild to smaller but still longish chains.
My main problem is still getting the copper salt in the first place.
I can get oleic acid from the hydrolysis of triglycerides found in many cooking oils. The glycerin could be removed from what would basically be soap
by simply pouring off the larger part initially. Next I could acidify the mix with HCl to create the free carboxylic acid. After this, I could
separate the carboxylic acid from the water with ether. I could let the ether evaporate and be left with a mix of long chain aliphatic carboxylic
acids and some residual glycerol perhaps. Now would be the stage to do any oxidative cleavage with KMnO4 but other-wise, how would I get the copper
salt of these acids since copper hydroxide is so insoluble in water and I don't think these acids will dissociate enough in water to really react
with the solid Cu(OH)2....
I know this can be made....copper oleate is a very common fungicide but I'd rather make my own of course!!
chemoleo - 19-1-2004 at 08:29
Hmm,
You will have to use the oleic/stearic acid salt of Cu(I), not Cu(II). In pyrotechnic mixtures, Cu(I) is used for colouring the flame. But, you may
have found that Cu(i) is easily oxidised to Cu(II), so you might have a problem in this respect. Also, I doubt that Cu(I)oleate will be easy to make
...
I would much rather try something simple at first, such as the same thing with Barium or Strontium. However, don't forget that a candle flame is
yellow in its own right, so that will certainly change the colour to a mixture.
The other problem is that the Oleic/Stearic acid salt needs to have a low melting point, else it wont go up the string in the middle of the candle. I
once played with some sodium oleate, and this still had a high MP, >300 deg C IIRC. Certainly not the temperature to get it liquid to travel up the
string where it could get burned (molten candle wax from a burning candle doesnt even burn you if you drop it on your skin! While boiling water
certainly does!). Do you think that Barium/Strontium/Copper oleate would have a much lower MP?
Nice as it sounds, I woldnt place my bets on your idea 
blip - 19-1-2004 at 12:39
Couldn't you just add some cuprous salt to the wick instead? I read somewhere that you have to soak it in some salt mixture and then dry, so why
not add some impurity? Too bad I don't know too much about candle-making, so if this sounds stupid please excuse my ignorance.
Al Koholic - 20-1-2004 at 20:26
Well as far as adding copper salts to the wick...I figured this wouldn't last that long really. I have these pine cones at home that are wax
coated and have lots of CuSO4 stuck to the wax. You put them in the fire and it burns blue for about 5 or 6 minutes and thats it. I imagine that
however the salt is being decomposed would still occur as the wick burned and because the salts might be gone before the wick burns down appreciably,
the blue wouldn't last that long.
By adding a wax soluble copper compound with a low melting point to the candle I should be burning the compound and hence, as long as the candle
burns, it will have a blue flame due to the additive. I have been doing some research on this and I have found that copper oleate can be obtained by
reacting K-oleate and CuSO4. I have the JCS reference (from Merck) and will check it out tomorrow probably. The melting point might be my only
problem as it could be significantly higher than the molten wax. If this is the case, I think a stearate or linoleate might do the trick. All of
these are relatively easy to come by through ester hydrolysis of triglycerides. Additionally, I think that if I get some impure fatty acid salts, ie:
a mixture of potassium oleate, stearate, etc, the melting point should be lower than any of the pure compounds alone which might actually help the
stuff melt into the wax! Think of how cool it would be to have blue or green flamed candles that once made, would only burn with that color!!! So
sweet....
Saerynide - 21-1-2004 at 00:22
Red-burning strontium candles would be nice. Or purple candles! 
kryss - 22-1-2004 at 11:06
What about just dispersing the metal oxide in the wax - I suppose the density of the MO is working against you. Or even a finely braided copper wick
Don't forget if it does work that metal vapours arent good for you!
Making a copper salt of a soap shouldnt be too hard, look how easy it is to make the Ca and Mg salts. Try boiling/simmering soap flakes in CuSO4
solution then filtering
chemoleo - 22-1-2004 at 11:50
Could you please explain how you want to get the metal-salt into the wick? If it is not molten, it wont, and will just accumulate in the molten wax.
Now, do you know of a copper/sr/ba salt that melts at 80 deg C??
Al Koholic - 22-1-2004 at 13:33
Actually chemoleo...I was in the stacks today reading synths for Al, Ca, Mg, and Cu soaps. The Cu soap I looked at was of course, cupric oleate
complexed with oleic acid. Its melting point is 83-84 C!!!
After mixing this into molten wax, there should be no problem with dissolution...
Oh, BTW...adding metal salts to the wick would simply involve dipping the wick in a hot saturated solution of the salt and then letting it dry out
before using it in the candle.
[Edited on 22-1-2004 by Al Koholic]
Darkfire - 5-2-2004 at 18:00
At this store i found a 5 pack of colored candels, red, green, blue, yellow and purple.
coloured flames
Pyroking - 4-3-2004 at 05:57
If any one does know how to make coloured flames from some fairly simple chemicals, ive been meaning to try this for ages!!!!!
AngelEyes - 4-3-2004 at 07:08
FFS...
This whole thread is about making coloured flame candles. All you gotta do is read....you can read, right?
I have read some of your other posts. It seems like you're either a bogus poster or a chump. You go to your Nans and use HE's in her compost
heap do you? So why in the name of twat do you need to know where to get KNO<sub>3</sub> et al?