Head Candle

Candles shaped like my head

Timespan: October 2021 - now

Published: 2024-02-01

One day, a long long time ago...

I needed to give someone a gift and wanted to give them a candle in the shape of their head. They countered with "I'd prefer a candle in the shape of your head", maybe to avoid seeming vain.

I found an app which generated a model of your head using just the iPhone front-facing camera. Take a 30-second video and pay a dollar, then voila! Head model in your email. What a glorious day that was...

3D printing your head was a pretty lame idea — it follows pretty easily from having the model. I wanted to take it a step further and decided to make a candle.

Here's some vague steps

I subtracted my head model from a solid cube in Blender/SolidWORKS and 3D printed some molds on my club's 3D printer.

One half of the candle mold I 3D printed. Resin printers > FDM

One half of the candle mold I 3D printed. Resin printers > FDM

Then I bought some beeswax and chunked it. Constructed a double boiler using two pots.

Beeswax surprisingly tastes nothing like honey

Beeswax surprisingly tastes nothing like honey

After pouring, the candle looks like this. The white bit is the wick.

After pouring, the candle looks like this. The white bit is the wick.

CANDLE TIPS THEY DON'T WANT YOU TO KNOW!!!!

I must warn you, pouring a candle is non-trivial. My first one failed because I put it in the freezer instead of leaving it out (rapid cooling means bubbles on face surface), and my second one failed because I dunked it in water (water displaced the still-liquid wax, leaving a cavity).

Failure mode of my second attempt

Failure mode of my second attempt

I also learned we needed some mold-release stuff to make the candle removal easier also, so I started coating the inside of the mold before pouring the wax. Oh, also wax shrinks as it solidifies so you'll need to top off the mold after waiting a bit.

My first proper head candle

My first proper head candle

The purpose of a candle is to be burned and provide light or smells. Unfortunately, I only ever gave head candles to people who really liked me — the people lease likely to ever burn a candle that looks like me.

I feel a weird tingling on top of my head...

I feel a weird tingling on top of my head...

In closing

The original head scanning app was called Bellus3D, and they really targeted rhinoplasty or other facial reconstructive surgery pre-work and analysis. Somehow they ran out of money and took the app down so you can't use it anymore.

Other apps for head scanning use the point cloud from the front-facing depth camera, which is much, much worse quality than doing photogrammetry (though I think a bit cheaper, computationally).

There are also some big neural network models that claim to generate 3D models from a couple of images, but there is no easy-to-run demo of this working probably because everyone decided to paywall it. Alas!

I think head candles are a great gift, and I still believe that giving someone a candle in the shape of their head is much more memorable and novel than giving them a candle in the shape of your head.