3D Printed Candle

Many of you at this point heard about 3D printing technology and even got your hands on making some stuff with it. 3D printing comes in really handy not only for prototyping purposes, but also as a very powerful production tool. In this instructable, I wanted to share my experience using 3D printing to make a candle. To make the candle, you don't have to stick with the design I used, in fact, try a different design, make your own pattern and share the results with me. I would love to see what you'll come up with!

When I first got into 3D printing and modeling, it was very hard to gather resources suitable for various skill levels, so I'm going to try to compile some of the most valuable. There are lots of softwares from very basics to fairly complex ones to get you up and running with 3D modeling. You decide how deep you are willing to dive in, but here's of the most popular ones.

Rhino 3D. Is probably the most well-known 3D modeling software often used by architects and product designers. It's very powerful tool that provides a lot of flexibility whether you design an object, landscape or a house. You can get Rhino free trial for the 90 days, then purchase it for 195$ if you are student.

Maya. Ideal for character creation and animation, very popular among animators and game designers. Also, if you know Python, it will be much easier to script in Maya. You can get a free trial for a month, but otherwise it's uber expensive, unless you are a students. They get 3 years for free.

3D Max. Similar to Maya, but a little bit more forgiving. But really it's just a matter of preference when it comes to choosing between Max and Maya. Probably a bit easier to understand and learn though.

OpenSCAD. It's a little gem for programmers. It's free and very easy to learn considering its impeccable documentation. OpenSCAD is less concerned with artistic aspect and focuses on geometry. Perfect for machine parts.

SketchUp. This free application is probably the easiest to learn and perfect for the absolute beginners straggling to understand basic concepts of 3D modeling. Caveats of SketchUp is that it’s not very precise, and, in my experience, people had a hard time transferring their files into 3D printers.

If you don’t feel like learning a new software, there are other great resource available. Thingiverse is a big open source community of people passionated about 3D printing. There you can find many good designs and ideas that you would like to try. Since most projects are licensed under Creative Commons, make sure to credit the person whose design you use. 123d is another software and open source community that could be a good resource in your experiments.

Materials needed:

1. PLA plastic for MakerBot. Could be bought at Home Depot, specialized 3D printing stores or Online.
2. Liquid Rubber or Silicon. I used brand Smooth-On, ReoFlex 30. It's very durable and works very well at capturing details. Easy to find brand (any arts and crafts store will have it) and easy-to-follow instructions, odor free as well.
3. 2 Small plastic containers - one to mix rubber in, another one to make mold in. Plastic cups or tupperware work well. Word of the wise: resist the urge to use that tin jar you found in your recycle bin- rubber adheres to metal, and you would waste the precious rubber!
4. Beeswax. There are many types of wax available on the market. My suggestion is to use beeswax, because it's non-hazardous and non-carcinogenic material, unlike paraffin. Soy wax is a good alternative, but not very environmentally friendly. Candlescience has everything you need to start making candles. But if you just want to experiment, you can simply remelt the candles you already have in the house.
5. Candle Wick
6. Glue gun

7. Thermometer

8. Scale

Optional: candle dye, fragrance.

First of all, whatever software you use to create your design, make sure you save the final design as an .stl file. STL file stands for stereolithography - a standard extension for any 3D software and will allow you flexibility should you make any changes last minute. MakerBot is most widely available printer, so I'll focus on its settings. To adjust the settings for MakerBot use their desktop application. Since we are going to cast the candle later, we want the printed object to be as smooth as possible with as few artifacts as possible (because 3D printing is additive process that extrudes material in layers, you inevitably going to have tiny stripes, that will be imprinted in your mold). To reduce this texture artifact - make sure you print at the highest resolution (see picture). Double check that the temperature for extrusion is set to 230C. Another way to go around the stripes is to send it down after printing, but that would add unnecessary labor. To proceed, export (save) your file in .x3g format - that's the format that MakerBots work with (see pic). Now put this file on the SD card (makerBots don't use other forms of flash card devices) and you are ready to print the candle. Proceed with printing. My print only took about an hour.

Now when you finished 3D printing, you are ready to make a mold for the future candle! Full disclosure: making molds is a lot of fun, you may get addicted to the process.

1. First, hot glue the 3D printed shape upside down to one of the plastic containers.
2. Then mix the liquid rubber following the instructions on the packaging using the other plastic container. You can use the scale for convenience. For a candle of approximately 2 1/2" high you'll need about 300g of each part. You would have to work fast as the mixture sets up quickly.
3. Pour the mixture into the container with the 3D object, covering it entirely. Leave the mixture to solidify over night.
4. Once the rubber fully cured, you can remove the 3D piece from the rubber. You can cut the mold for easier removal.

There are few things to keep in mind when you start making candles. It could become a dangerous affair pretty quickly if you are not careful. Keep in mind, wax can’t be melted on direct heat, because it's flammable - you have a short window between your wax melts and starts burning. Make sure you use a thermometer. The safest way to melt wax is a water bath or double-boiler. The way to do it in home without special equipment is to have two pots-one to boil water and a small pot for the wax.

If you cut your rubber mold in half, make sure to put it back together and secure position with the rubber bands.

Fill the larger bot with water about quarter way up and start heating it up. Put the wax in a smaller pan and stack it inside the bigger pot. Use a thermometer to track the temperature.

Once the wax reaches 185F degrees, you can add color dyes in.

Remove the wax pot from the heat, add fragrances if desired and mix thoroughly. Leave it to cool down.

While the wax is cooling down, place the wick inside the silicon mold and secure it in the middle with the hot glue.

Once the wax is cooled to 135F, it is ready to be poured into the rubber mold. Leave the wax to solidify over night.

Next day, remove the candle from the mold. Your candle is ready to be lit up!

Enjoy!!