Cast Cement Incense Burner + Tea Light Holder
Introduction: Cast Cement Incense Burner + Tea Light Holder
Hi Instructables! It's been a while since I last published anything, and I'm stoked to finally have something to share again. This project grew out of a simple paperweight I designed as a practice project to help me get more comfortable with casting. The more time I spent with the paperweight, the more I liked the shape, so I started trying to come up with other things I could make that borrowed from its design. I settled on an incense burner / tea light holder combo, and I love the contrast between the heavy, industrial look of the finished product and the softness of fire and colourful incense.
I decided to use quick-setting cement instead of concrete for two reasons: 1) I'm lazy, and didn't want to wait for the concrete to cure (days for concrete vs. hours for the cement); and 2) Since the burner is so small, I didn't want to have to deal with large pieces of aggregate.
It's designed for shorter, Japanese-style incense such as this, but it will work with most types of incense. The benefit of using the incense highlighted here is that the ash falls into the burner, making for easy clean-up. If you plan on using it for longer or thinner incense, it's a good idea to put a plate underneath to catch any ash that may fall outside the burner.
Step 1: What You Need
Supplies:
-Quick-setting cement (I used Quikrete anchoring cement)
-Vaseline, or similar (for lining the mould)
-Water
-40 gauge (~0.12mm) copper or brass foil
-1mm thick cork sheet with adhesive backing
- 1/8" brass rod (you can use another metal, but brass rods are easy to bend)
-3 elastic bands
Tools:
-Small container for mixing concrete
-Wooden sticks for mixing concrete (I used a chopstick and a skewer)
-Trowel or small shovel
-400 (or higher) grit wet-dry sandpaper
-Hacksaw, or similar metal cutting tool
-Scissors
-3D printer or printing service
-CAD software (I used Fusion 360)
Step 2: Designing the Mould
You have two options for the mould: 1) download and print the .STL files I've attached below; or 2) make your own!
If you choose the first option, I recommend printing the files with a 0.2mm layer thickness and 20% infill.
If you choose to go with the second option, I highly recommend checking out this excellent Instructable by Further Fabrication. 787
It really helped me develop my mould. I won't try to re-state Further Fabrication's instructions here, but I will offer a few general tips/some useful information I stumbled across during the design process:
1) If you plan on making a similar shape to mine, I recommend using a three-part mould. When I tried to make a two-part mould that combined the "Lower Walls" and "Base" files, it was hard to remove the casting without cracking it.
2) Try to avoid having any walls thinner than 8mm. I found that thinner walls were prone to caving in and/or cracking when de-moulding.
3) Shapes with more aggressive draft angles and continuous profiles (shapes where you can freely "twist" the mould) are a lot easier to work with.
Step 3: Preparing the Mould
-Cut a ~5cm length off the brass rod, and bend the top 1-2cm at a slight angle. The rod will form the hole that holds the incense. The bend at the top makes the de-moulding process a lot easier.
-Put one of the elastics around the smaller diameter opening of the "Lower Walls" print, like in Image 2. This helps center the "Lower Walls" in the "Base", and doubles as a gasket to prevent any cement from leaking out during casting.
-Liberally coat the 3D printed mould parts and the longer straight section of the brass rod with Vaseline. Try to apply as smooth of a coat as possible.
-Assemble the mould (from top-to-bottom: brass rod, "Upper Walls" print, "Lower Walls" print, "Base" print) and hold it together with the two remaining elastic bands, as shown in Image 4.
Step 4: Casting
-Mix cement and water until it has the consistency of pancake batter (thick, but still flowable).
-Pour the mixture into the mould, stopping just (~1mm) below the top. 220