Sciencemadness Discussion Board

Colored Candles/Halloween Stuff

Jackson - 31-10-2018 at 08:28

Im trying to do some colored flames for halloween on some candles. Im trying to do red and green flames. I think im going to use lithium (lithium hydroxide) for red and boron (from borax) for green. I plan to mix the salts directly into the candles (parafin) but im not sure if they will be soluble or produce a colored flame. Should I mix the salts with methanol to form Lithium Methoxide and trimethylborate and then add that to the candle or do I not need to do that.

Assured Fish - 31-10-2018 at 15:24

This is actually a fantastic idea, however some points need to be made.
Boric acid/oxide will not burn green on their own, i think it is the nature of the organic boron oxide bond that emits the green wavelengths of light when oxidized, im not certain but i suspect the same would be true of lithium.
Trimethyl borate should in theory be miscible with paraffin as trimethylborate is miscible with alot of other hydrocarbons such as mineral oil and hexane.
I would suggest preparing trimethylborate and trying to mix it with molten parraffin.
There is some risk with doing this of coarse as parraffin melts at about 50°c and trimethylborate boils at 68°c and is quite valatile.
Care should be taken and this should be done outside and you should make sure to keep your heat source for melting the paraffin away from the trimethylborate.
Im not sure what would happen upon solidification of the mixture but i suppose if the borate was keept at a low concentration in comparison to the wax then they should solidify and the borate should be kept trapped in a suspention throughout the wax. (Dont quote me on this though).

Jackson - 31-10-2018 at 15:28

Yeah my main concern with using a thing that is liquid at room temperature in a solid candle is that it wont solidify completely.

fusso - 31-10-2018 at 15:32

For the Li salt, you probably need something lipophilic, like butyllithium (beep~:P) no, its fatty acid salts like stearate.

Jackson - 31-10-2018 at 16:05

Could I just drop lithium metal into molten parafin?

fusso - 31-10-2018 at 16:09

Quote: Originally posted by Jackson  
Could I just drop lithium metal into molten parafin?
Eh...I don't think Li will dissolve any significant amount into it to make the flame red?

Texium - 31-10-2018 at 18:10

Quote: Originally posted by Jackson  
Could I just drop lithium metal into molten parafin?
No. Paraffin is just a mixture of long chain hydrocarbons. Lithium would not react with it, just as it doesn't react with mineral oil. You would need to get a saturated fatty acid, like stearic acid, and make the lithium salt of it, for which you could use lithium metal, or preferably something cheaper like lithium carbonate, if you have it. Then you can take that fatty acid salt and mix it with the molten paraffin.

sodium_stearate - 1-11-2018 at 06:08

Not quite sure this would work, but I'll mention it anyway:

Speaking of the salts of a fatty acid: I use a few in my
process of making the old "brown wax" that Thomas Edison
used to record sound on the old "wax" cylinders.

In my case, the metal is aluminum, and the salts
are sodium and aluminum stearate.

The process by which the metals react with the stearic
acid is as follows:

A small amount of pure aluminum metal is dropped into
a solution of sodium hydroxide and water.
The aluminum reacts with the lye.
The resulting solution is filtered to remove particulates.

The clear solution is then added portionwise to
hot melted stearic acid, and then cooked until all
precipitate is dissolved in.

The end result after a few hours is a type of wax.
It is actually saponified stearic acid with trace amounts
of sodium and aluminum.

Possibly a similar type of scenario might be used with
the lithium as a way to get it bound in with some
stearic acid. Then the lithium stearate could possibly
be added to the paraffin of the candle.

Not so sure lithium would react with lye, but from my
limited knowledge, I'd guess it may. Just an idea.

DrP - 1-11-2018 at 06:16

How about just dipping the wick in the salt solution and getting the wick coated with the salts? I think it might burn with a better colour than just impregnation of the wax. I seem to remember reading somewhere that wicks were dipped for this and doping the wax doesn't actually work that well.

Endo - 1-11-2018 at 06:36

I prefer strontium salts for red flame effects. An old road flare can be a great source. Just peel it, break up the charge inside and dissolve whatever will dissolve into a minimum of hot water.

With crystallization and evaporation the strontium salts can be used as a spectra imparter for a brilliant red in stars, and flames ect.

I wonder if impregnating the wick itself with the salt would give the effect desired.

Good Luck

DrP - 1-11-2018 at 07:11

Quote: Originally posted by Endo  

I wonder if impregnating the wick itself with the salt would give the effect desired.

This is what I have read several times before when looking into it. You impregnate the wick to get the flame colour not the paraffin.

I tried to dope some spirits with Strontium salts once to get a red flame and copper for green - it was a bit red/green but not great. With hindsight I would have impregnated the wicks I was using instead. I don't really do fire spinning with poi so much these days though otherwise I'd try it. :-)

Sulaiman - 1-11-2018 at 07:17

The green of boron is easily overwhelmed by the yellow of soot or sodium,
the only 'nice' green flame that I have made used boric acid in methanol with a fibreglass wick.
Even ethanol adds colour to the flame, as can a cotton wick.

DrP - 1-11-2018 at 08:11

Quote: Originally posted by Sulaiman  
The the only 'nice' green flame that I have made used boric acid in methanol with a fibreglass wick..

Useful to know - the copperI salt I used wasn't great - but it was in the fuel not the wick - which is what seems to be advised from reading about on the internet.

DraconicAcid - 1-11-2018 at 09:20

You want to use an alcohol burner, not a candle.

TheMrbunGee - 1-11-2018 at 10:11

Just as test I sprinkled some lithium oleate in burning melted candle, this does not color the flame, maybe tiny little unnoticeable bit of reddish, but nothing remarkable..