A little known technique, and it's a shame, is that of the cold water bath.
Indispensable to create a hurricane shell, it will also likely come to your help for other types projects.
Let's take a look at this technique and what it involves.
The main reason to use a water bath in your candlemaking projects is to speed up the cooling process of the paraffin contained in the mold you dip in the water.
This technique is mainly used when making Hurricane shells, for two reasons: to fix the shell inclusions in place faster and prevent them from floating to the surface of the wax, and speed up the cooling process of the large volume of paraffine necessary for a Hurricane shell (something that would take hours at room temperature).
Another advantage of the water bath technique is that, by speeding up the cooling process, it gives a shiny finish to the candle (more about this in the article 3 easy surface techniques for your candles). This explains why Hurricane shells always have that shiny aspect.
Before you choose a container for a water bath, look at your collection of molds and pick the widest and the highest ones (it could be the same mold or two different ones).
The container you will use must:
The first time I made a Hurricane shell using the water bath technique, I used the mold you can see on one of the pictures that illustrate this page. As you may notice, the bucket is just large enough for the mold. Fine, so I fill the mold with about 5 kilos of 194°F paraffin wax, tap its sides with a spoon to help release any air bubble (and doing so I give the mold plenty of time to become burning hot). Then, like a fool, I burn myself trying to lift it up bare handed. Second attempt, I pick it up by its base, that isn't too hot yet, and plunge it in the bucket. Except that, half way down and before the bottom of the mold even reaches the water surface, my hands get stuck between the mold and the sides of the bucket and the mold won't go any further. As it happens, my hands get squished against the hot mold again and I burn myself a second time. And that is when the pain forces me to drop it all... and 5 kilos of hot wax end up in the water.
To make a long story short, always go with the next size up if you can. Better too large than too small...
I strongly advice against using oven gloves to lift and move a mold full of hot wax. There is always a minimal amount of paraffin wax that will end up on the outside of the mold and make it too slippery to be safely handled with gloves.
A better idea is to DIY a simple mold handler.
This unsophisticated device can be as simple as two lengths of electric wire (choose it thick enough, at least 5mm) bent and placed under the mold's base; it will let you easily move a burning hot mold around.
Just because the purpose of the water bath is to speed up the cooling process of hot wax doesn't mean the water in the bath must be ice cold. Actually, it's much better if the water is at room temperature; it is more than enough to "suck up" the heat of the mold and the wax without risking to crackle the surface of the candle or ruin the mold and/or its weldings through a sudden and important change of temperature.
By the way, did you know there's also such a thing as a warm water bath? Specific projects require that the candle would cool off as slowly as possible, like container candles or candles with a mottled surface effect. In this case, it is possible to dip the mold (or container) in a warm water bath and let the mold cool down slowly, together with the water in the bath.
While I'm talking about containers, remember you should never use the (cold) water bath technique when making container candles. Not only must a container candle cool down as slowly as possible to avoid contraction of the wax, but because most containers are made of glass, there's a risk that the thermal shock would make it burst.
Paraffin wax floats on top of water. In other words, your mold full of paraffin wax won't sink by itself to the bottom of the water bath: you will need some kind of ballast.
When you buy a mold weight from a candlemaking supplies store, you get a long, flexible lead cylinder you can wrap around the mold to increase its weight.
Two problems here: they can be tricky to find nowadays; secondly, it's LEAD, not exactly the safest thing to have around.
Fortunately, the homemade alternative works just as well and is much safer too: just run to the nearest DIY store and buy a meter of the heaviest chain they carry. At each end, attach a piece of rope, about 30cm long. Wrap the chain around your mold, just above its base, and use the ropes to secure the chain. Easy as 1,2,3.
If your mold doesn't really have a base (only metal molds tend to have one), you'll need to find a heavy item and put it on top of the mold so that it won't tip.
The most important variable in the water bath technique is certainly the water level in the bucket: too high and water will flow into the mold, too low and a unsightly line (called cold line) will be visible on your candle.
The ideal situation, and that's what we're aiming for, is when the water level in the bucket exactly matches (or is a few millimeters higher than) the wax level in the mold.
Obviously, to achieve this, you need to be sure about two things:
The first condition is no real problem as all you have to do is decide once and for all that you will fill your molds up to 1 centimeter from the top and no further (it is recommended, by the way, not to fill a mold all the way up to the top because of the risk of mixing water and wax).
As far as the water level is concerned, some preparatory work is indispensable.
First, make sure your bucket is empty. Then, fill your mold to the maximum level you've decided upon in the previous step and put the mold weight in place (very important because the weight will displace some water as well and must be taken into consideration).
Now place the mold in the empty bucket and fill the bucket with water until the water level reaches the water level in the mold (it's a good idea to add 3 to 5 millimeters to be on the safe side).
Now, carefully take the mold out of the bucket. Allow water to drip back from the mold into the bucket for a few seconds. The level of water in the bucket is the level you'll have to reproduce for THAT mold with THAT type of mold weight.
You should now clearly mark that level using a piece of waterproof electrical tape (be sure it won't go off even after it's been submerged in water) or draw a line with a waterproof, permanent marker.
As you probably have more than one mold, repeat this process with any other mold that might end up in a water bath some day. Do not forget to identify the marks in the bucket so that you can tell which mark belongs to which mold: use different colors of electrical tape or write a letter or number next to each mark.