'oil slick' swirl on candle tops

[aviking]

Hello, I've been making candles for 5 years and lately, I've been noticing at an 'oil slick' effect on the top of my candles. Tops are really smooth and looks nice, but there is a swirly oil 'sheen' when light reflect off the surface as if there is a very thin layer of oil resting on the top. Any idea on how to fix this? Or is this the new normal? This seems to be the case with all the FOs I try (from several different companies as well as my own blends). Here is my process:

 

Wax: GB 464, Heating to 190 degrees, adding 9.5% FO immediately, stirring for 3 minutes, pouring at 135 degrees. 

[Moonstar]

can you post a pic by chance ?

[aviking]

Here are two pictures. One is in a glass container and hasn't been heat gunned – so you can see how the top forms naturally. The second on in a tin has been heat gunned and you can see it's nice and smooth but the oil 'swirls' are there.

 

To me it looks like the FO isn't blending in 100%, but I'm not sure why. I'm only at 9.5% FO load. 

[Trappeur]

Well, right off the bat Aviking you have waaayyyy too much oil you are using. So I would back down on that.

 

Now I have had that look on the top happen to me a few times but not at that low temperature you have poured, but a much higher temp like maybe 159 (that was an accident)...it really doesn't look like an oil slick to me...but it probably is with as much oil as you have used.

 

Not to change the subject, but how is that jar burning?  Looks like an awful big wick to me.  what jar are you using and what size wick if you don't mind me asking?

 

Trappeur

[moonshine]

That is a very high FO load - if you have been using this much for 5 years and are just now seeing this 1- I am amazed and 2- another case of absolute affirmation soy wax is NOT anywhere near what it used to be 

[DCC]

I See people saying it could be due to fragrance load. I work for a candle manufacturer and I was asked to look into swirls like this. I honestly thought it was due to the wick wax from the remelt process. There is some truth to that but I am actually noticiing siwrls when I dye wax and pour with no fragrance or wick as well. It wont let me past a picture directly into here and do not have a URL to insert image.

[DCC]

Hey, got it to work! This is not a soy blend and has no fragrance.

Edited December 14, 2022 by DCC

[BenderSF]

I can't help to answer the question, but I get the same thing sometimes.  Candles with dye sometimes look exactly like your photo, and candles without dye sometimes have that "oil slick" look like aviking's pic from 2017 above.

I haven't taken meticulous notes on this issue, though, so I've never been able to determine a pattern on when I see it vs when I don't, but I know I've seen it in paraffin and in soy, scented and unscented, dyed and undyed...which really only leaves wax or process.

[DCC]

I've been testing different variables for a couple days now. Surprisingly, when I used heavier fragrance loads, the swirls are less prominent. When I compared 10%, 15%, and 20% fragrance loads in the lab (we commonly use 10-15% for production), the higher fragrance loads had less swirl. The worst of this effect was with no fragrance.

 

One of the things I tested was topping off the candle vs going through a remelt process. The top off did have some color variation on top but nowhere near that swirl effect.

 

Next, I'm going to see the difference between barely remelted vs overly remelted. Update tomorrow!

Edited December 15, 2022 by DCC

[TallTayl]

4 hours ago, DCC said:

I've been testing different variables for a couple days now. Surprisingly, when I used heavier fragrance loads, the swirls are less prominent. When I compared 10%, 15%, and 20% fragrance loads in the lab (we commonly use 10-15% for production), the higher fragrance loads had less swirl. The worst of this effect was with no fragrance.

 

One of the things I tested was topping off the candle vs going through a remelt process. The top off did have some color variation on top but nowhere near that swirl effect.

 

Next, I'm going to see the difference between barely remelted vs overly remelted. Update tomorrow!

The uneven surface is likely due to the components and additives in your wax blend.  Every additive in commercial wax has a purpose driven by consumer demand (better glass adhesion, less shrink, higher fragrance load, etc). Each of those additives has different melt and drop temps., and they coalesce at different rates (causing uneven surfaces as they stretch and shrink during cooling).  
 

Adding that much fragrance does several things, such as diluting the additives, or wetting the wax crystals for longer in the candle.  As the candle ages sometimes those additives continue to shrink along with the recrustallization of the wax crystals the,mselves and cause tiny, inconspicuous voids where fragrance begins to seep and pool. 
 

Process improvement potential: often heating the wax to reach the melt point of the component with the highest melt temp, followed by thorough and complete blending as the wax cools improves the finish.  
 

adding more fo% is a viscous cycle.  As fragrance retailers stretch the dollar with more and different diluents to keep the price point profitable, the wax  manufacturers are tasked with making normal wax hold more of those diluents. I have moved away from most FO retailers for that reason.  It should not take 10%-15% to have a wonderful candle that burns safely, cleanly and throws hard.  I may pay more per lb for my FO custom from the lab than most are willing to pay from a retailer, but I use a fraction of the % and end up with better candles (and soap, shampoo, melts, etc)..  

[NightLight]

I work with wax with things other than candles, as TT said if you have different components in the wax you can get that look in wax.

Take that candle you posted a photo of and try heat gunning it. I have balm that always does this cooling but after it solidifies,I heat gun and it’s perfect. My product is a combo of a high melt wax and low melt and they cool different times in cooling process.

[DCC]

Focusing on why my employer and our contracts use such a high amount of fragrance load is digressing from the question. Is it necessary? No. Does it sell for a higher amount? Yes.

 

In everything I was testing, it seems to always come back to the remelt process for the swirl appearance. I took different fragrances, fragrance load, and combination of different waxes we use to all have similar behavior if I increased or decreased the time in our remelting. 

 

My conclusion is that if there is an appearance of swirls on top (not a texture, just a visual), minimizing remelt time caused them to no appear. I was able to mimic it back and forth. Took a candle with no swirls and over melt it again under the heaters and the swirls came back. Gave the same candle a minimal amount of time under the heater and they went away.

 

I know the caveat is what limitations and variables from my lab but hope this helps give some info to others.

 

Thanks for everyone’s input!