4630 tops sunken

[jbrooks]

So I've made 6 test candles (8 oz smooth sided jelly jar) with 4630, all with same fragrance but different sizes and types of wicks. I have a real problem with the tops not being smooth, they're sunken in towards the wick pretty significantly. I'm heating to 180-185 in the Presto then ladling into warmed fragrance in a warmed pouring pot (Pyrex.) I have tried pouring at 175 and 165, I have poured into warmed and unwarmed jars, I have left them on the countertop and I have put them into a Styrofoam insulated box/cooler to cool. Still all the tops are sunken, every single one. Other than a repour or a heat gun, is there anything else I may be able to do to fix this? Thankfully I am not having a big problem with wet spots, just the tops.

Also, I read different things, but is there a "recommended" curing time for 4630? I ask because they all having outstanding cold throw but I started to burn one after less than a full 24 hrs to test the wick and there is no smell whatsoever unless I lean right over it. I'm sure that less than 24 hrs isn't enough time, but is there a recommendation of time to wait?

Thanks so much for any input!

[rjdaines]

I use 4630 and rub into slightly sunken tops only with larger diameter containers. While it's supposed to be a single pour wax, it does shrink a little. Why yours are behaving as they are I can't explain. I heat to 185, add cold FO, heat to 180, stir, and pour at 175 into cold containers. The containers are nestled on a cork mat and left to cool.

I am not a believer in curing but do wait a week to test burn. Not all FOs will work in all waxes. To test if it is the wax or your system, make some melts and test those. If you get good HT, then your system is not optimized and, most likely, you need to find a different wick. I find that a weaker burn works better than a more vigorous one.

[jbrooks]

Thanks for the advice RJ. Do you mind if I ask which series of wicks you tend to have the best luck with? I'm testing HTP, LX, ECO, and Zinc. I like the look of the HTPs and ECOs the best but I realize that doesn't mean anything at all. I read a lot of people having good luck with HTP and Zincs in this particular wax, so just curious what works for you.

[ksranch]

I use 4630 too, and echo what RJ said. I was zincs in my system.

[jbrooks]

Thanks KS. Do you also go for a weaker burn instead of a hotter one? Do you tend to go for a full melt pool on the first burn? I know this is a good wax for throw, I'm just trying to work out the kinks to get it to throw for me As far as the melt thing, I have poured any leftover wax into little melt cups and when put in the warmer, they throw really well, so I know its not the wax or fragrance, its the system for sure.

[rjdaines]

Don't go for a FMP on the first burn, by the end of the candle you will have a hot and sooty mess. As for wicks I use a variety as dictated by the container size and the FO. These wicks are HTP, ECO, and CD. Many people use zinc with great success but I have not tried them.

[jbrooks]

Well so far it seems that the zincs are working out best for me, second would appear to be LX. I have pretty much fixed the bad sunken tops problem but HT is still almost non existent for me Also, when I said earlier that I didn't have a problem with wet spots, I take it back. Its really hit or miss for me. A couple have no wet spots at all, a couple start with none and then develop several, and some look like one big wet spot. Thankfully wet spots aren't a huge concern for me, but it does seem like there's no rhyme or reason to them forming.

I am planning on trying some more waxes. I like the look of soy, but know I will prob have heat throw issues with it as well. I ordered the small sample sizes of GB 464 soy, IGI 6006 parasoy, and IGI 4627 paraffin from Peak today after I got the email about the 25% off shipping sale. I figure since I'm just starting out my best bet will be to try multiple waxes that interest me and see which I initially prefer, and then work on perfecting all the elements for that wax.

Thanks again for all your help everyone! As a newbie I appreciate any and all input!

Edited October 31, 2013 by jbrooks
Additional Info

[Vernie1]

In my experience with 4630, the tops would sink if I poured around 160 and less. I notice the temperature drops really quick with this wax, so you must pour around 180-170 to avoid sunken tops. For me the best wicks are the htp's, the eco's and cd wicks were too big. This wax doesn't need big wicks such as soy wax. I think I used this wax straight with no additives, with 1.5 oz fragrance and get great ht.

[Candle guy]

I use 4627 in the jellies. I have the same issue with sunken tops. I have great HT and use lx wicks. I always have wet spots no matter what I do. I just grew to accept them. I ordered a 4630 sample and it's on its way. I have zinc wicks so I will experiment with them with this wax. Hope everything worked out

[Former Member]

Candles get sunken tops when they cool too fast. We all know that wax shrinks when it cools, but have you ever thought about HOW a candle cools? Understanding the nature of the cooling process is the key to solving this problem...

 

If every part of the candle cooled at the same rate then you would end up with a candle that has a flat and even top. But every part of the candle does not cool at the same rate. After you pour a candle, the first part to cool is the bottom. This is because the surface that your candle is sitting on dissipates heat more efficiently than the air surrounding the candle. As a result, this portion of the candle cools the fastest. If you haven't witnessed this yourself, next time you pour a candle you should notice that the bottom of the candle is the first part to become opaque. How fast the bottom cools doesn't really have an impact on whether or not the top will sink. It could affect whether or not you get wet spots around the bottom, but ultimately, how the tops of candles turn out is more dependent on the rate at which the sides and top portion of the candle cools.

 

The next part of the candle to cool are the sides. This is because the glass is also good at dissipating heat. It is not quite as good as the surface that the candle is sitting on but still better than the air on top of the candle. You should notice that when the sides of the candle become opaque, that the center of the top of the candle is still somewhat dark and fluid. Once the sides cool, they will stay at the same height in the container and will not shrink down the sides anymore as the rest of the candle cools.

 

After the sides cool, the top is next. When the top cools, it will seem flat and even for a short period of time, but gradually become sunken as the candle sets over the next several hours. Why does it sink? Because the center is the last part of the candle to cool. The center of the candle is insulated from the air and surfaces that are dissipating heat, and therefore cools the slowest, but still shrinks the same amount as the rest of the wax. This creates a negative pressure in the center of your candle. Gravity won't allow the bottom of your candle to compensate for this pressure change (not to mention the vacuum this would create on the bottom of your candle), so the bottom stays in place. Do the sides compensate for this pressure change? Yes, to a certain extent. This is where wet spots come from. But the top of the candle is the most affected because it cools later than the bottom and sides of the candle and is therefore more flexible during the time of this pressure change. This is where sunken tops come from.

 

Now that we know where sunken tops come from, we can address the issue of how to prevent them. In order to prevent sunken tops, you need to manipulate the environment that the candles cool in so that it dries from the bottom upwards, not from the outside inwards. You need the center of the candle to cool before the top to avoid this pressure change. This might seem like a complicated thing to do but is actually relatively simple and straight forward. All you need are some heat lamps!

 

By allowing your candles to cool under heat lamps you can ensure that the top is the last part to cool and avoid the pressure change that causes the sunken tops. Personally, I let my candles sit under a 250 W heat lamp, about 2 ft above the candle for 1 hr. Then I let them sit under a 125 W heat lamp, about 2 ft above, for 20 mins. After this I turn the heat lamp off and let the ambient air do the rest of the cooling (the tops are opaque by this point anyways). The tops, while not exactly flat, are flat enough that you wouldn't feel the need to take a heat gun to them. Here is a candle after this process:

 

 

Edited March 4, 2016 by hapathy
Better pic

[grama]

The simple solution is to simply do a repour.  Save enough wax after you pour your candle.  After it cools melt your wax and just repour enough to get to the original top of wax from first pour.