Dynamask is a great way to protect and clean up your proof of concept circuit boards when you're testing and iterating your final design.
Dynamask can be finicky, below are the basic guidelines to make a perfect mask every time.
Clean the board with acetone. The board should be cleaned completely.
The following steps are UV sensitive, perform them in a dim lit area to minimize exposure to UV radiation. (stay away from natural sunlight)
Remove the frosted layer from the Solder Mask. (use two pieces of tape)
Affix one edge of the mask to the board, rolling smoothly across the surface lightly to prevent trapped air bubbles or wrinkles.
Trim excess mask away from board, when heated it will become very sticky, if excess material adheres to the laminator it will be difficult to remove.
Prepare heating tool
Set iron to the 'wool' settings or set the laminator to the hottest position.
allow adequate time for the heating element to reach temperature.
If using a laminator no protective coversheet is required, Run the board through the laminator 3-4 times.
- If using an iron, lay a paper towel or teflon sheet over the circuit board. Apply pressure to the board with the iron while moving it around slowly to distribute the heat evenly. (around 15-20 seconds of the hot ironing, do not over heat)
Submerse the board in cool water immediately for best adhesion.
Expose the dynamask side of the board (approx. 45 sec. at 4×15 watt UV or 5-10 minutes in direct sunlight depending on intensity)
Lay down the board: :45-:60 minutes in a dark place to allow for the mask to cure!
Remove the second (shiny) layer. (use tape)
Develop in 1 liter water and 10 grams developer at 45C/113F degrees.
Use a soft acrylic brush for developing. Gently rub the board until solder mask desolves away in unexposed areas..
If things haven’t worked out OK completely, you can just leave the board in the developer. After a few hours, everything will be dissolved and you can start all over again. In this case you need to make new developer.
After developing do not touch the Solder Mask.
Rinse with water and let the board dry.
Expose 30 minutes to harden under UV or direct sun light
Time to assemble your board!