Most of the candle making eBooks are in PDF form, so they’re easy to download and save. If you know of any others, let me know. My eyes are beginning to bug out and I had to stop searching for the day.
This is a well written free manual that shares some cool candle making tricks! This is where I first found out about using Crisco for increasing scent throw in candles.
There are simple straightforward instructions on how to make soy candles here.
This has more on soap than candles, but you’ll find some interesting information and recipes here. It was originally written in the 1800s, so some of it is outdated.
The first 37 pages is free and it offers a fun lesson on votives with details on equipment, timing, temperature, amount of wax, additives etc. I love his advice on breaking up a big slab of wax. He basically advises you to smash it on the floor once it’s at chest level and/or hit it with a hammer. Luckily, I figured that one out on my own.