colored fire candles

[Givat]

Hi guys,

I found this a video of a guy who made colored fire candles

http://www.metacafe.com/watch/701569/how_t...e_colored_fire/

 

I don';t know how reliable his "science movies" but this one sound logical.

 

As we know some metals ions can give light in the spectrum that our eyes see as different colores.

Strontium = red

barium\copper = grenn

sodium = yellow

......

 

In the movie a coton string is dipped in a solution of XCl (X=metal). and used as thread in a candle.

 

I tried this with strontium nitrate and the flame is yellow with a little red in the lower part of the flame. I think the yellow is more dominant.

as far as I know there isn't any sodium in the paraffin.

 

 

Any thoughts what to do for colored candle?

[asilentbob]

Too much charcoal/carbon to get good colors.

[Bonny]

Bluesquib has made some candles I think. See here:

http://www.apcforum.net/forums/index.php?showtopic=844

[GraafVaag]

With no chlorine, there won't be much colour. Try strontium chloride. (You can react SrCO3 with an overdose HCl, and cook it in.)

 

Ever tried making red fire with just Strontiumnitrate and fuel? It will look somewhat reddish, but you'll never get true red. (Exept with Mg, for some reason.)

 

If you don't have SrCO3, try an other chloride. Or plain CuSO4..

[Givat]

My bad, I used strontium chloride, not nitrate.

 

 

As I understood from BlueSquib, if the wax is mixed with enogh chloride it will burn colored.

So any why there is solvent for paraffin and ionic substance?

 

I'll try tomorrow to make the candle in layers - one paraffin and one chloride.

[Bonny]

My bad, I used strontium chloride, not nitrate.

 

 

As I understood from BlueSquib, if the wax is mixed with enogh chloride it will burn colored.

So any why there is solvent for paraffin and ionic substance?

 

I'll try tomorrow to make the candle in layers - one paraffin and one chloride.

I think the way to do it is to melt the wax and mix the metal salt into it. That way as the wick sucks up the wax it also draws up the salt.

[Givat]

the salt in the wax sinks to the bottom.

 

I tried to make red candle again today, I dipped the thread in the wax and rolled it in SrCl2 powder. I did several dippings until the I had 1 c"m thick candle.

 

this candle burnt with a little red halo, but after some minutes the wax melted and burnt and the thread left coated with the salt. is extinguished itself after some burning.

 

I guess this is the reason you can't buy colored fire candles in stores, if it was that easy to make - some one would have already made it.

 

I think I nedd different fuel, any suggestions?

[Mumbles]

Most of the colored flames I've seen are liquid fueled, and even these collect salt in the wick, except for perhaps boric acid.

 

The main problem I see is avoiding excessive smoke. Obviously candles burn relatively cleanly. Small amounts of smoke if any at all really. The other thing one must take into consideration is decomposition product. Obviously most of the common colorants are moderately toxic. No company in their right mind would sell strontium or barium colored candles. As many of the colorants are actually chloride species, one must also take special care to avoid any excess chlorine being released as chlorine gas or HCl.

 

I have a feeling that to make good colored candles, it would take significantly more work that just embedding salts into the wax. I'm just thinking out loud here, but I see several obstacles that must be overcome.

• Non-toxic colorants and end products
  
• An oxidiser to help remove the extreme carbon excess present in paraffin
  
• A chlorine donor. The first one that obviously comes to mind is chlorowax. It is simply chlorinated paraffin. It should be readily mixable, perhaps even soluble. Parlon also comes to mind, but might retard the burn to too large of a degree.
  
• Actual decomposition of colorant. It's obvious that stable salts like strontium chloride are going to vaporize minimally, and are obviously not soluble in paraffin. I was thinking something along the lines of benzoates or other carbohydrate based fuels. The other that came to mind was peroxides. These would increase the burn rate of the candle obviously, but also increase heat of combustion, which I think is also a problem.
  
• Low flame temperature. It's likely that the fuel isn't getting the salts hot enough to vaporise enough to make good colors. I already mentioned the possible use of oxidisers to raise flame temperature, and decrease excess carbon. One may also use metal fuels. I believe this is actually how those trick birthday candles that don't go out are made. Pieces of metal are incorporated into the wick, which stay hot enough to reignite the wax after one blows them out.
  

 

Honestly, I think in the end, it'd end up more like a pyrotechnic composition, than a candle. I can forsee this being mixed up with paraffin similarly to whistle mix(via a solvent or heat), and being pressed into candles. By the time you get a workable composition, it probably wouldn't be safe to use indoors.

[GalFisk]

Colored flame candles are being made commercially. I read a couple of patents, they both mention using a different fruel from normal wax, to limit the amount of carbon in the flame. One of the designs used a separate wick to introduce the coloring compound to the flame, the other had them in the wick and wax. Unfortunately I don't have the links anymore.

[Rogue Chemist]

https://sciencemadness.org/talk/viewthread....tid=7220&page=1

 

Look for posts by Dr. Beaker. It is how to use metal salts in the wax for coloured effects.

 

Mumbles, would a strontium candle really be that bad? Of course barium would be foolhardy, however strontium does not share the toxicity issues with barium.

[Givat]

I tried this metal soap idea and got a failure.

I made a Sr soap out of a canola oil soap I made 5 weeks ago. this soap was dried and mixed with wax (2:1, wax:soap).

I made this mix into a candle and tried it, it burned like all candles but had some "flashes" of red halo from time to time. I call it a failure.

I found out that the 2:1 mix can burn by itself after some of the larger soap chunks are burnt and for some reason function as a thread. and this didn't gave any better red too

 

for last I tried putting some HCE and PVC(about 5%) to see if this helps - no difference.

[WarezWally]

Apparently you just mix the salts in with the wax according to a eBay ad I noticed some time ago (was selling carbonate and chloride salts)