Fisherck

The material that the paint is on should not have any affect on the resistance (as long as the material itself isn't conductive). You can control the resistance by either changing the amount of graphite powder you put in the paint, or by how much of the conductive paint you apply to the paper (a thicker coating will be less resistance). Paper should work fine, but one thing I would be careful about is making sure to not bend the paper too much after the paint is applied, because that could cause the paint to crack and break the circuit

For the most part, the bottle cap size is pretty universal. I haven't found any bottle caps that won't fit this. I designed the cutout so that the 4 semicircular grooves were just a little larger than the diameter of the bottle caps, so that they would have an interference fit. This will allow a little bit (but not much) of leeway, and if the bottle caps are smaller, they won't stay in place, and if they are too big, they won't fit.

Glad you enjoyed it!

Similar to what you're suggesting, this could probably be done fairly well with a cnc machine. It would solve the problem of burnt edges with laser cutting. The main difficulty that I would see would be a way to hold down the chocolate (because it is very brittle), and also you would be more limited by how small you can make parts. But it may be well worth it!

Thank you! Both the starch and the laser cutter do have an impact on the taste of the chocolate (which is why I tried a bunch of different things before trying a thickener). The starch is pretty subtle to me, but it did change the texture of the chocolate. However, I only used starch because I had that handy; I bet you could find a thickener that is not as grainy and would have less impact on the taste. As for the taste caused by the laser cutting, if you're eating along an edge that's burnt, it has a taste that most reminded of burnt chocolate chip cookies (not terrible, but definitely a negative impact on the taste).

Thanks! Glad you enjoyed it. It is pretty neat what kinds of things you can potentially build out of chocolate using a laser cutter.

Thanks! Yeah, unfortunately having access to a laser cutter can be difficult. This is a project that you don't need a very strong laser cutter for, so you could probably use very low wattage laser cutters/engravers to cut chocolate.

That shouldn't be a problem. The bottle caps have an interference fit with the grooves, so they get wedged in and stay there pretty well. If the bottle caps are very bent, they might slip out ocassionally, but otherwise it should work fine.

Great question! I just realized that I didn't explain that part very well in my Instructable. I added a GIF up at the top in the introduction to show how to take on/off the back.

Glad you enjoyed it !(: