DIY Spin Coater

YouTuber Bridbrain had an application where he needed to deposit a very thin layer of insulation, on the order of one micrometer – a thousandth of a millimeter – onto a surface. This is obviously a huge/tiny challenge, but thin deposits just happen to be the purview of spin coaters, capable of spreading a liquid down to the 10s of nanometers – i.e. hundredths of a micrometer. The problem with spin coaters is that they can cost thousands of dollars/euro, so BBE decided to make his own.

Considering the expensiveness of professional rigs, BBE’s DIY spin coater is actually pretty simple, and quite reasonable price-wise at around $69 in parts and materials. The base of the spin coater is an Arctic P8 Max 80mm PC fan, with four wires that allow for PWM control and RPM feedback.

The fan was sawed in half, and a number of 3D-printed parts were applied to hold the part-under-spin in place and protect the motor. A 25-CD spindle case was modified into the spin chamber, and an overall housing was 3D-printed to fit the mechanical parts and electronics together.

As for control, BBE first considered using an Arduino Nano, but after finding it didn’t have the computational horsepower he needed, instead settled on a Raspberry Pi Pico. The build was finished off with a 4x4 keypad and a microSD card reader for input/storage, along with a 2x12 LCD display for user feedback.

While it appears there is still a bit of work to do to get coatings uniform, it does indeed cover surfaces at a fraction of the price of the professional version. Hopefully we’ll see it perfected and put into use in a future video. For now, code and other project files are available on GitHub if you’d like to build – or build upon – this device.