Let's make a box!
To make a chocolate mould we need to assemble a vacuum forming table. Vacuum sheet forming is the simplest and least expensive of all thermoforming processes. A sheet of hot plastic is is blown in to a bubble and then sucked onto the surface of the form. A vacuum forming table basically is a simple box with some holes on top to create a suction area.
To make this box I’m using a sheet of 2x2 feet MDF, 1/4” thickness and two poplar boards 1”x3” x 2 feet. As a reference for my table dimensions I used a letter size sheet of paper.
I used a 45 degree miter joint to create my box, but you can use any joinery method for your box. As long as you have straight corners you will be fine.
Cut your top and bottom panels to the size of your frame. The top panel will be our suction area, so we need to make some holes there. I marked a grid to drill my holes so they are approximately an inch apart from each other.
After I drilled all my holes (including a hole on the side of the frame for my vacuum connection) I attached my panels to the frame with some drywall screws.
Making a mould.
From the same piece of MDF I made a frame to hold up the plastic sheet. I've attached the plastic sheet to it with binder clips. The more binder clips the better the edges of the form will hold the shape.
But before you put plastic in the oven, you need to create a razed support for the frame there, so you have space for hot plastic to stretch down. I put 4 ceramic bowls in the oven to create a support for each corner of the frame. For plastic I'm using a food safe PET plastic, 0.5mm thick . Preheat your oven to a 350F. Don't forget to use oven mittens then you working with hot stuff. Put your frame with mounted plastic sheet on it in the oven for about a minute or two. Get the frame out of the oven as soon as the plastic sags 2-3 inches below the frame level.
Put it over the running suction table. And in seconds the plastic magically will be shaped around your object. It takes some practice, and depending on your plastic you will need to play with the heat settings.
Melt some chocolate chips or baking chocolate in a double boiler. Pour it in the mould and put it in the fridge to cool down. Super easy! Now you know how to make an awesome custom chocolate. You can use different objects to create the form. It would make a great present or a
sweet treat for yourself. =)