You are looking for an idea to decorate your table or cocktails on Halloween?
This tutorial will help you realize some decoration for your drinking glass (glasses that will contain your monstrous cocktails!). Those decors are quick and easy to create. A 3D printer can create one in less than one hour.

We are going to explain the steps to print them, and use them with the patterns of your choice. You will find the needed files at the end of the tutorial, to print and modify them at your will.

Supplies

A 3 printer

PLA filament

Boiling water

A container for the printed fla

Step 1: The Idea

A 3d printer is used to print a thin plastic sheet, with some patterns and drawings stenciled on it.
The sheet is very thin, to make it fast to print. Usually, glasses are vertical, but it's harder to print a vertical shape than a flat one. Furthermore, every glass has a different diameter length, and it's not easy to measure it beforehand. Therefore the main idea of this tutorial is to print those flat sheet of plastic horizontally, flat on the printer bed. The plastic used is PLA, so after the print, you can dip the plastic sheet into boiling water to soften it and apply it around a glass, and then let it stiffen in a few seconds.

PLA is going to soften at boiling water temperature, but not melt completely. You can then shape it as you wish (be careful to not burn yourself with boiling water !). We don't recommend to use ABS, because it's not based on corn starch like PLA for this specific usage.

Step 2: The Plastic Sheet

The plastic sheet, of dimensions 15cm x 10cm x 2.5mm, has been designed with OpenSCAD. SVG images and patterns are then duplicated, rotated and scale on that plastic sheet, substracted from it, to create stencils.
The liquid of the glass is going to be seen through the holes created by the drawing. Be careful to use drawings without 'unattached' parts. Any part that isn't attached to the contour is going to go away when substracted from the main plastic sheet!

Step 3: Boiling Water

We use a cake mold, which has the right depth, to have the whole sheet be enclosed in it.
We then pour boiling water on it, one or two centimeters deep. You can retrieve the plastic with a fork, and apply it directly on the cylindrical part of the glass. Don't burn yourself with the water or the plastic!

If you use a soup bowl to hold the glass, you can pour water on the glass after the plastic has been put on it if you want to change the shape a little bit.

Step 4: The Glass

If the plastic sheet is larger than the glass, you can cut some parts with a pair of scissors, since the sheet isn't very thick.
Fill the glass with orange, red, or green sirup and water to give a nice effect to the glasses!

If your PLA isn't food safe, remind your guest to not put the plastic part, around the glass, to their lips!

The template should be made with some extra plastic material at the bottom of the plastic sheet, so it can be cut away if the glass is not high enough.

Step 5: OpenSCAD

The file are create with a main flat cube for the plastic sheet, in OpenSCAD.
Some SVG is loaded and repeated to create the top pattern of the decor. This pattern is can be different from the main design, and changed to add some variations Other SVG are loaded, rotated, scaled and shifted to create holes in the plastic sheets.

We also provide the original drawing, made in Affinity Designer, and put in the public domain (the original design is our, so we release them here for free).