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White Soot Test

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Tired of taking people's word about whether or not soy makes soot, and whether it's white, I'm doing an experiment.

I just got some ridiculously large wick (CandleScience CSN-26) and am trying it with EcoSoya CBA in a 6 oz hex jar that, properly wicked, would use a CSN-9 (for soy) or CSN-7 (for palm). Touch of yellow dye, no scent.

So far...

I'm right. Soy can soot, and the soot is black. Score one for physics there. The only white soot I could find reference to on the web, other than in soy promotion, was from the tetraethyl lead in aviation fuel. Or, the remains from a magnesium fire. That makes sense. Metal oxides can be white. Carbon can't.

Furthermore, if soy didn't produce fine black carbon particles, the flame wouldn't have that nice yellow glow. The glow is from those carbon particles getting very hot. If the mix is right, the carbon completely oxidizes into CO2. A sooting flame is just throwing off cooler particles that never have a chance to burn up.

However, I have to admit that this candle isn't sooting much, and sometimes burns like in the picture. Nice perfect curling-over wick and a decent flame height. Normally my soy candle flames are kind of anemic looking, if sized to make normal depth melt pools and not roast the glass container at the end.

This wick is a _rope_. It's a bit bigger than 42 ply. I was expecting a cloud of black smoke. I'll burn this off and on down to the bottom (in a safe enclosure), and see if it comes out with glass as black as a lot of paraffin containers end up being.

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Soy will soot just as black as paraffin will if not wicked correctly, I discovered it when I first started experimenting with soy. I was really surprised because I had always "heard" that soy don't soot. Should have saved my jar for the proof :cheesy2: :cheesy2:

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This has been discussed here many times if you do a little searching. All candles soot when burned. And as grama pointed out overwicking a candle will result in black soot. The difference in the color of the soot has a lot to do with the type of wax. Then there are factors that add to that such as additives; FOs, wicking, etc. Anytime you burn a candle the wax is the fuel which is consumed by the flame which produces a byproduct; soot.

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The difference in the color of the soot has a lot to do with the type of wax.

I think that's the assertion that this test is intended to refute.

Soot is that black stuff that comes out of a disturbed flame. There's only one kind that I've ever seen. Nobody has ever seen white soot for the same reason nobody has ever seen a unicorn.

For a clue as to how this stuff gets started, head to your local craft fair and look for the hypo-allergenic candle vendor.

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  • 2 weeks later...


White soot, my foot. Not surprised, but there it is, on the jar in the photo, and in person it clearly is throwing out the occasional black plume. Black, I say.

ON the other hand, I have to admit that it seems like soy is a lot more forgiving than paraffin in terms of wick size vs. amount of sooting.

If I'd overwicked, say, 4630 paraffin this badly (LX-30-ish), I'd probably have a flame licking the rim of the jar and throwing out continuous soot. Not really scientific if I don't try, but I have had 1274 LX-12 votives or small 4630 containers sooting much worse than this soy candle. Granted, the soy here is pretty much unscented, but still. You're one or two sizes too big with paraffin, and you have a sootfest.

Why do I bother? Well, I might have the chance to talk to the owner of Candlescience over lunch, and when I met him at the warehouse sale he did say something about white soot. I don't _want_ to disagree with someone I respect, and who has a Chem E background, but at least now if the subject comes up I have a concrete example instead of just my novice chandler's (1 yr?) suspicions vs his extensive experience.

Oh, and in case you're curious, I didn't know the bit about the yellow part of a candle flame being, essentially, burning soot until I read this: The Chemical History of a Candle by Michael Faraday, from 1861. It may be old but, largely, candles haven't changed a bit since then.


There sure is some bafflingly bad info out there about "natural" wax, though. This site, for example, claiming that beeswax flames are so hot that their light is more like daylight than candlelight. i.e., it has a flame that's around 6000K instead of the more usual neighborhood of 1000K (727 C). Boy would we have some wicking issues with beeswax if that was the case. Then, there's the whole organic beekeeping thing, but that's a whole 'nother subject.

I just don't understand how crap like that ends up getting posted on so many websites. It's like someone, somewhere, comes up with some marketing BS, probably knowing it is BS, and then everyone else comes around and copies it.

Here's another one that really takes the cake: "Melting point 65 C (149 F), highest melting point of any known wax." Really? No, really? 65C is that remarkable? I had _no_ idea. Sigh. I guess overdip wax is a true undiscovered country.

I have trouble being comfortable making reasonable claims about my candles, and so many others maybe don't think twice about running with ... well, whatever.

By reasonable I mean the kind of text you see on legit sites, but which strikes me as "filler": long burning, highly scented, finest wax, true-to-life scents, etc. Not to mention estimated burn times.

I mean, they're candles. Humanity has been familiar with the technology for thousands of years. What can you really say about a competently made candle that really means anything that the customer isn't already perfectly aware of? They may not trim their wicks, and might be dumb enough to burn pillars unattended, without a holder, on top of a stack of newspapers; but, I bet they have an idea how quickly candles tend to burn, at least if they've ever had any that don't spill out the side or tunnel down a few inches and drown their wicks.

As for playing up scent quality, that just seems too subjective to say much on. Though, I sure wish I could buy some boutique manufacturers' FOs like Illume's Sahara Sage.

Maybe it's just the engineer in me. I look at one of my candles and think of what isn't _wrong_ with it. What's good is, well, expected. I made a candle that doesn't suck - great! But seems to me that is just an ordinary... candle.

"It's not crap" isn't exactly great ad copy, though.

Edited by radellaf
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