Your safety is paramount! Before you start melting the wax (let alone the candle Gel) that will give substance to your first candle, please make sure you are in possession of an adequate thermometer. It could not only save your life but will also help you achieve predictable and consistent results: how a candle turns out greatly depends on the temperature at which the wax is poured in the mold or the container. Here's another incentive: if you add scent to your candles, you need to be sure that the temperature of the wax is not higher than the flash point of your fragrance oils. That would certainly "burn" your fragrance oil and kill the scent.
If you can and want to afford the investment, your first choice should be a digital infrared thermometer, lightning fast, precise and contactless. Or go for the less expensive alternative: a digital probe thermometer, the type used to check if a piece of meat is cooked the way you like it. Depending on the model (and its price), it takes a few seconds to read the temperature of the wax.
Non-digital options are also available, like the candy thermometer, built into a metal frame, which is originally used to help make jams and caramel. It can be clipped to the side of the melting pot for a permanent reading of the temperature.
Another possible choice is the deep fry thermometer, consisting of a probe which dips into the wax and a dial on which a needle indicates the temperature. This one clips on the side of the melting pot too.
Whatever type of thermometer you choose, it must be able to precisely measure temperatures up to the flash point of paraffin wax, which is around 392°F. That's more than sufficient because, believe me, you really don't want to be around if the temperature of your wax rises above 392°F...
Let me now talk in more detail about those four types of thermometers and how we can use then in candlemaking.
This one is quickly becoming my best friend. Completely contactless, an infrared thermometer is capable of precisely reading the temperature of your wax in under one second. Just aim, pull the trigger and voilà!
Pretty expensive less than two years ago, competition has made the prices drop like bricks and today, a small forty bucks gets you a very decent model with a range of -58°F to 1472°F.
Available in a large range of models on Amazon.
If you don't make (and don't intend to make) Gel candles nor any special projects that require melting the wax on a direct heat source (like sand candles that demand for the wax to be heated to 266°F), a digital probe thermometer will do the trick. If it offers a very precise reading of the temperature, it is however not made to remain dipped in melted wax for long periods of time; you will use it to check the temperature at regular intervals. Most digital thermometers can handle temperatures ranging from -58°F up to 572°F.
In my case, I use my digital probe thermometer after I've transferred the paraffin from the melting pot into the pouring pot, to know when I can add fragrance oils and when the time has come to fill the mold or the container. A few seconds are enough to get the exact temperature of the was inside the pouring pot, which makes this thermometer a very useful tool. Ideally, you would own two thermometers: a digital one and one of the first two models we talked about. With them, you're ready to safely embrace almost any candlemaking project.
For about seven dollars, Ikea offers a two-parts digital probe thermometer; the probe can stay in the wax at all times while the case is placed safely away. This model, called FANTAST, reads temperatures up to 482°F.
It's easier to find a digital probe thermometer locally than the other models: if you live near a very large supermarket, you should be able to find one there. If not, look online, for example on the Amazon website. A cheap model sells for about ten dollars, a reliable one will set you back twice that amount.
This was the first thermometer I purchased and it's still my favorite to this day. Well protected from blows in its aluminium frame, you can clip it on the side of your melting pot and leave it dipped into the melted wax. Most models available on the market offer a double temperature reading, in Celsius and Fahrenheit degrees, which can be very practical if you follow tutorials written or video'ed by a foreign candlemaker.
As I said earlier, this kind of thermometer is originally used by confectioners to check on the temperature of sugar syrups: it is capable of measuring temperatures ranging from 104°F to 392°F, which makes it a perfect tool for us candlemakers too.
If your intention is to make mainly paraffin or vegetable wax candles, maybe it's better to go for the model I am going to talk about next. The reason for that is that the frame of a candy thermometer features plenty of creases, edges and openings in the aluminium, not to mention the clips that hold the glass tube in place... all of that makes for a real nightmare to clean up when your candlemaking session is over. On the other hand, it works perfectly with candle Gel because the latter peels off easily once it has cooled off.
You might be able to find one in stores that specialize in kitchen accessories but you will probably have more luck online, at Amazon for example. Depending on the model and the manufacturer, expect to pay between 10 and 20 dollars.
The deep fry - or dial - thermometer is a very good alternative to the candy thermometer. Maybe even a better one for the simple reason that it's way easier to clean than the previous one at the end of your projects... Because it is originally made to keep track of the temperature in a deep fry kettle, there's nothing surprising about the fact that most models can handle temperatures ranging up to 554°F, even though the cheaper ones tend to stop at 392°F.
The deep fry thermometer is made of a dial that displays the temperature and of a probe you dip into the wax. Its clip (make sure the model you purchase does have a clip, otherwise it's pretty much worthless) allows for easy fastening to the side of the melting pot; just like with the previous model, you can monitor the temperature from beginning to end. This model comes recommended for paraffin and vegetable waxes: only the probe comes into contact with the wax and is the only thing you will have to clean at the end of the day.
Like the candy thermometer, you might find it in stores that specialize in kitchenware accessories. If that's not an option in your neighborhood, the world wide web is there to help you. Amazon has several models on offer ranging from 5 up to 30 dollars.