I’ve been making candles for about three years now, and since getting into pottery the combination of the two mediums has become a regular topic of discussion.
I decided to make my own candle vessels because pouring melted wax into pre-made containers didn’t really feel ‘hand made’ enough for my brand. I joke that I don’t consider something to be ‘hand made enough’ unless I bred both it’s parents and chose its name. Making the candle vessels certainly seemed like a step in the right direction, and designing cute vessels was the icing on the cake. Hence the birth of the Candle Cauldron, a stylised ceramic cauldron designed to be sold as a candle, that can then be used as a planter or trinket dish or refilled and used again as a candle.
It seems like every second person is starting their own candle business these days, and the internet certainly makes it look like a simple undertaking. But if you care about the quality of your product and don’t want to be responsible for burning anyone’s house down, you really need to take a breath, do lots of research and most of all do lots and lots of testing.
This blog is mainly for those wanting to put soy candles in hand made ceramic vessels. Mass-produced candle vessels are readily available and come with a long history of other people testing them, so a little search will tell you which supplies best suit which vessels. But for unique hand made vessels things are a little trickier.
Is my vessel safe?
Most pre-made candle vessels are made of glass, which is universally accepted as a safe medium for candles. Ceramic of the same thickness is stronger than glass and better able to withstand high temperatures. So if your ceramic vessel is stable and fired to the required temperature to vitrify your clay, it should be at least as strong as the glass equivalent.
Most glass vessels are cylindrical, but when making your own vessels there are a few things to consider. A tall thin vessel will use a smaller wick and the candle will last longer than in a broad shallow vessel, but may not put out as much fragrance due to the smaller melt pool. I aim for broad and fairly deep vessels with straight sides. My cauldrons are roughly spherical with large openings.
Preparing for re-use
Remove the wick tab and as much of the wax as you can with a metal spatula or blunt knife. I pour boiling water into the vessel and let the wax melt before tipping it out and wiping with paper towel. You could also wash in a sink of hot soapy water, or even put them in the dishwasher. Make sure your vessel is completely dry before refilling.
Why soy wax? The truth about working with soy wax
The main candle waxes available are paraffin, soy, palm, beeswax or coconut. Most cheap candles found in department stores use paraffin, which is derived from crude oil, or palm wax, which comes with a host of environmental considerations. If you are someone who avoids palm oil, you will probably want to avoid palm wax. Soy wax is made from soy plants, and most of it is grown in the USA, meaning no rainforests are cleared to grow it and no poor communities are exploited to obtain it.
The thing about soy wax, as a natural product, is that it can be a little temperamental. For best results, you need to work at fairly specific melt, mix and pour temperatures to get a good-looking candle. It is very inclined to frost (discolour) if you add colour to it, it is also quite prone to pulling away from the edges of your vessel (mainly evident in clear vessels) and it can be a bit ugly on top when it re-sets after burning. These issues are the price of admission for using pure soy, but fortunately most customers don’t even notice.
Choosing your wick
When you buy vessels from a candlemaking supplier, you get all the useful information like how much wax the vessel holds and which wick is recommended. You still need to test these to make sure your combination of wick, wax and fragrance gives you a good burn, but when you get it right you’re set. When you make your own unique vessels you have to figure this out yourself, and because no two vessels are exactly the same you really only get one go at it.
I use CDN wicks, which are made in the USA and are widely available. There are plenty of wick size charts online, and when you find a good one you can print it out and post it over your candle making station or store it with your notes. I prefer to choose a smaller wick than suggested in most cases. This will stop your vessel from getting too hot. Over time, as the candle burns down and warms the vessel, any wax left stuck to the clay near the top should melt. If you choose a wick that is too small you risk the candle ‘tunneling’ or the wick drowning in the wax, which you also want to avoid.
Vessels over 10cm diameter should be double-wicked. This reduces the depth of the melt pool and increases the burn time. When double or triple wicking you want the total burn pool of the wicks to equal the diameter of the vessel. I haven’t gone beyond three wicks in a 12cm diameter vessel, but if you are making much bigger vessels you can search for multiple wick suggestions.
Finding the volume
To find the volume of your vessel, put it on a scale, zero the scale, and pour in water until it gets to the desired wax level. Record the weight of water. This is the volume of your vessel.
Converting to wax weight
To convert the volume to the weight of wax required, multiply by 0.9. Wax is lighter than water, so you need less weight of wax to fill the vessel.
Fragrance ratios, and a bit about fragrance oils
Doing the math to find out how to convert your wax weight to a ratio of wax and fragrance is confusing. Fortunately there are apps to help you. I use an app called Candle Maker which allows you to enter the wax weight for your vessel, and the fragrance ratio. It then tells you how much wax and how much fragrance, by weight, you need to fill the vessel.
Safe fragrance levels in soy wax are up to 10%. Beyond this you risk the candle catching fire or the fragrance preventing the candle from burning properly. Many fragrance oils are quite strong at 8%, some at 6%. Test your fragrances at different strengths to get to know them and how they perform. Some fragrances are strong as soon as the candle is set, others require a cure time of two weeks. Some aren’t ever going to be strong enough for your liking. Most candlemaking suppliers sell fragrances in small enough volumes to make a test candle, so you can try out several before buying in larger amounts.
Why not essential oils?
Many essential oils are toxic when burned, others are flammable, others are too volatile to use in candles as they evaporate at fairly low temperatures. If you are really keen to use essential oils because they are ‘natural’ be sure to do plenty of research to find out which ones are safe for candle making and at what rate. I use loads of essential oils in my soapmaking, but stick to specialised fragrance oils for my candles.
Melting your wax, melt mix and pour temps
Each wax comes with a recommended melt, mix and pour temperature. These can usually be found on the website where you buy your wax. Sometimes there is a range of suitable temperatures, and you will need to refine your process with testing over time.
To melt your wax you can use a double boiler or a wax melter. I use a small rice cooker which can melt up to 1kg of wax at a time. You can use this time while your wax is melting to attach your wicks to the bottom of your vessel using either a glue gun, a little bit of BluTak, or a wick sticker dot. Make sure to centre your wicks using a centering tool or a skewer across the top of the vessel that you can twist your wick around to hold it straight. Wicks will flop when the hot wax is poured in, so you can’t rely on them just to stand up straight.
Keep track of the temperature of the wax, and when it gets to the desired temperature, weigh the melted wax into a mixing jug. Once the wax cools to the mixing temperature, add your pre-weighed fragrance oil and mix until the wax appears clear again. Monitor the temperature and once it reaches the recommended pour temperature, pour it into your prepared vessel.
If you get your temperatures right your candles should have a smooth top with no sinkholes. You can re-set tops with a heat gun if they are uneven, but you’ll get the best result if you can get it right the first time.
Hot throw/cold throw
Candle fragrance is described as ‘throw’ and different fragrances have different strengths of throw while burning and while just sitting around cold between burns. You might like a candle that smells strong before you light it, or one that really fills a room with scent once lit. I’ve probably tested 50 different fragrances, and of those there are about 8 that I use regularly. I choose fragrances with good hot throw that don’t need much cure time.
Curing
Some wax and fragrance combinations give a better throw if the candle is allowed to cure for a couple of weeks before burning. I have found candles made months earlier that had weak fragrances to begin with but have become much stronger over time. Generally, a fragrance that is strong straight away will perform better than one that is weak to begin with but improves after curing.
Some fragrances will discolour over time, especially those with high levels of vanilla in the mix. If you are giving away or selling these you want them to be as fresh as possible when they arrive at their new home, so a long cure time might not be practical.
Burning the candle including melt pool and wick maintenance
All candles should be sold with a warning label and preferably a candle care card outlining the safety issues and how to get the most from a candle. Burn on a heat-proof surface, away from flammable items. Do not leave the candle unattended while burning, keep it out of reach of small children and pets.
The first burn of a large candle should be for about four hours, long enough to almost melt the entire top of the candle. This is called a full melt pool. After the initial burn always try to allow the candle to achieve a full melt pool before extinguishing it. Wicks should be trimmed to 5mm between burns. CDN wicks in soy wax are prone to ‘mushrooming’ if the wick is allowed to get too long, which causes a bigger flame and faster burn. Burnt wick ends will snap off in your fingers to the right length, but if you don’t want to get soot on your fingers a wick trimmer is a handy tool.
In multi-wicked candles always light all the wicks every time you burn the candle.
Can I put flowers in it?
I never put anything other than wax, fragrance and wick in my candles. Things like petals, leaves, bits of bark and crystals pose a fire hazard or if you are lucky they will just drown your wick. Plenty of people do it and get away with it, but I don’t, and I recommend against it.
So that information should see you safely making candles in your ceramic vessels, or refilling vessels you already have. There are various Facebook groups you can turn to for info, and a lot of the suppliers also have tips and tutorials on their websites.
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