Specific gravity of FO, and wicking

[calan]

Being "that guy" that's always looking for logic in things that sometimes aren't logical...

Has anyone ever done any wick testing to see if there is a correlation between the specific gravity of fragrance oils and the necessary increase or decrease in wicking from a baseline of pure wax? I want to think that there should be a correlation.... that a FO with a similar SG to another FO should require roughly the same type of wick adjustment, all else being equal.

I understand that each FO formulation is going to have different burn characteristics, but I've found over the years (especially in things like race fuels, some exotic paints, etc), that SG is usually a pretty solid data point to make comparisons from.

And if there is (or could be), is there a source of data for the SG of common FO's from each manufacturer? (Guessing this is where it starts getting murky).

Just curious.

Edited September 26, 2019 by calan

[Forrest]

That is a good question.The experts on the board will tell you that certain fragrance categories tend to need to be wicked up, or down. I might be able to test this as I have 19 FOs that I have wicked for 6006. I would just need to test the density and compare it to the wicking. If they correlate it would make initial wicking much easier. I may try that when I get the time.

 

[calan]

I only have small sample bottles of FO right now, so not enough to measure with my old-school tube/hygrometer....otherwise I'd be all over it myself. 

[Forrest]

1 hour ago, calan said:

I only have small sample bottles of FO right now, so not enough to measure with my old-school tube/hygrometer....otherwise I'd be all over it myself. 

Beware the sample size FOs, they are highly addictive

[bfroberts]

31 minutes ago, Forrest said:

Beware the sample size FOs, they are highly addictive

And they breed like rabbits.  I started with 5 or 6 and now I have hundreds.  It's shameful.

[calan]

5 minutes ago, bfroberts said:

And they breed like rabbits.  I started with 5 or 6 and now I have hundreds.  It's shameful.

Oh I know. The little bastards.   lol

I have over 200 bottles of food flavors for the same reason.

[Kerven]

I don't know about most suppliers' and manufacturers' - good luck figuring out which manufacturer(s) a supplier is sourcing from - spec sheets on fragrances and whether or not they publish or have them available upon request. However, I did take a peek at Candlewic because I know they have MSDS and SDS for waxes. Turns out, they do supply the sheets for some of the fragrances. Candlescience and WSP also have MSDS/SDS sheets for some fragrances.

[calan]

Did you happen to notice if they show the specific gravity?

I'll check some out when I get a chance.

 

[Kerven]

They do, although, I can't vouch for their accuracy.

Of the sheets I glanced over, some had specific gravity values that appeared a bit suspect. For example, one supplier had sheets for a few vanilla fragrances and, although they were different formulations, the values were exactly the same (1.01) with a +/- .05 margin for each. That wasn't the case for most sheets, however, so I would consider them fairly reliable with a grain of salt; keep an eye out for standard copy-paste values.

Some will use relative density instead of specific gravity.

Edited September 27, 2019 by Kerven

[calan]

13 minutes ago, Kerven said:

For example, one supplier had sheets for a few vanilla fragrances and, although they were different formulations, the values were exactly the same (1.01) with a +/- .05 margin for each.

I'm no chemist (by any stretch), but that may not be an invalid observation. Assuming all vanillas are well... vanilla (), it might be that the differences in formulation cause very small changes to the SG.

I would be interested to see what happens when a vanilla is mixed with something else, like tobaccos, etc., or how they compare to known lighter fragrances.

Edited September 27, 2019 by calan

[calan]

Maybe we could get a sticky thread where people can list the SG's of various FO's as they come across them, and see if any patterns start popping out? I dunno...I'm just weird like that.  lol

 

@TallTayl ... thoughts?
 

Edited September 27, 2019 by calan

[candlesinflorida]

30 minutes ago, calan said:

Maybe we could get a sticky thread where people can list the SG's of various FO's as they come across them, and see if any patterns start popping out? I dunno...I'm just weird like that.  lol

 

@TallTayl ... thoughts?
 

Is it too lame to ask, what is specific gravity? And what could it tell us about the candle making process? (Slept through hs science and went to a college w/ zero actual requirements-but now I am interested!)

[calan]

24 minutes ago, candlesinflorida said:

Is it too lame to ask, what is specific gravity? And what could it tell us about the candle making process? (Slept through hs science and went to a college w/ zero actual requirements-but now I am interested!)

 

In simple terms, it is a measurement of a liquid's density, or viscosity...usually measured in reference to a standard such as water.

As for why I brought it up, it seems that there should be a correlation between the viscsoity of various FO's, and how easily they are drawn into a wick. I was just curious if this holds somewhat true.

In other areas, SG is usually a pretty good tool for comparing and predicting how various types of fuels, paints, plastics, etc. will react in various conditions... all other factors remaning equal.

Edited September 27, 2019 by calan

[TallTayl]

Specific gravity is an interesting question to ponder, but not for the reasons we might think. WSP used to publish that info on the CoA. I chose one of the fragrances I love from them, Oakmoss Sandalwood. CoA used to be great to know to figure out if your FO bottle was full or not. 

 

Could not find the CoA for it, but read the SDS (http://www.crafters-choice.com/PDFs/ProductDocs/7276-SDS.pdf). this was the most inclusive SDS I have ever read. It contains a full list of major components in the composition of ingredients section. There’s nothing special I can see regarding the SG of the fragrance, but man does it need a wicking down usually.  Now I want to compare this SDS to something I know requires a wicking up, like a patchouli or vanilla or lemon. A very small % of patchouli in a blend makes my usual wicks fizzle requiring a big wick up.

 

back to specific gravity for a sec. one of my fragrances, Dragons Blood, needs to be wicked up in coconut wax, and wicked down heavily in soy blends. Same bottle of FO, so the same SG. There’s something Chemically changing that burn between the waxes.  The same phenomenon occurs with several fragrances, and in reverse with others. Perhaps pH is a better rabbit hole to chase.  Or the chemicals in the compound like on the WSP SDS. 

[TallTayl]

5 minutes ago, TallTayl said:

Specific gravity is an interesting question to ponder, but not for the reasons we might think. WSP used to publish that info on the CoA. I chose one of the fragrances I love from them, Oakmoss Sandalwood. CoA used to be great to know to figure out if your FO bottle was full or not. 

 

Could not find the CoA for it, found the SG to be 1.034 in the SDS (http://www.crafters-choice.com/PDFs/ProductDocs/7276-SDS.pdf). this was the most inclusive SDS I have ever read. It contains a full list of major components in the composition of ingredients section. There’s nothing special I can see regarding the SG of the fragrance, but man does it need a wicking down usually.  Now I want to compare this SDS to something I know requires a wicking up, like a patchouli or vanilla or lemon. A very small % of patchouli in a blend makes my usual wicks fizzle requiring a big wick up.

 

Here’s the SDS for wicker upper, Black raspberry vanilla. http://www.crafters-choice.com/PDFs/ProductDocs/3905-SDS.pdf

 

Ironically no vanilla in there.  SG is 0.983. 

I noticed there’s no isopropyl myristate in this one. That is a propellant type ingredient, so maybe this in the Oakmoss sandalwood is a culprits. 

 

5 minutes ago, TallTayl said:

 

 

back to specific gravity for a sec. one of my fragrances, Dragons Blood, needs to be wicked up in coconut wax, and wicked down heavily in soy blends. Same bottle of FO, so the same SG. There’s something Chemically changing that burn between the waxes.  The same phenomenon occurs with several fragrances, and in reverse with others. Perhaps pH is a better rabbit hole to chase.  Or the chemicals in the compound like on the WSP SDS. 

 

[Kerven]

There are other factors that influence wicking such as surface tension of the wax pool, oxidation, and polymerization. Oxidation and polymerization also apply to the wax and its performance. There are various bits of literature (scientific articles, patents, books, technical docs, etc.) discussing the use of antioxidants and other additives to improve the performance and stability of waxes and difficult fragrances. GE has a several years old document floating around out there (it's even mentioned somewhere on this forum) promoting the use of organo modified silicones and even states formulations that were specifically designed to improve the performance of, for example, vanillas. Some national brands are using BHT as an antioxidant in their candles.

Solvents in the FO could also play a role in compatibility with certain waxes. For non-phthalate (those without DEP) fragrances, IPM is the go-to, although DOA is said to have better performance - even in soy, which has a habit of smothering fragrances.

Fragrance traveling up the wick isn't so much the problem as the scent is released from the molten wax. I suppose, FO's could sink in the molten wax, unable to breach the surface if their SG is greater than the wax's and convection currents within the wax aren't strong enough to move it (might be related to viscosity), but then SG variables change because the wax's temperature rises above those used to calculate SG. That doesn't mean there couldn't be a correlation between SG and wicking adjustments. 464's SG is 0.698 - 0.921, so going by that line of thought any FO with SG =< 0.921 should perform well not taking into account other factors (viscosity, surface tension, temperature, solvents, additives, etc.). I'm curious to see if there's a connection between SG and flash point as well, because the FO's that worked best for me in 464 had flash points < 200F.

 

If we could compose a list of difficult to wick FO's and track down their SG it would be easier for comparison.

[calan]

22 minutes ago, Kerven said:

Fragrance traveling up the wick isn't so much the problem as the scent is released from the molten wax.

I was thinking more in terms of how the FO might affect the wick's ability to draw fuel and sustain a certain burn rate/flame height...not so much the impact on throw.

Some very good info you posted up there ^.