To add a professional finish to my boards and protect them a bit I like to cover them with a solder mask. To do this I have used a 3 mils dry film solder mask Dynamask 5030 from the Dynamask 3000 series. Applying this at home requires the following.

• KiCad
• Inkscape

• Dynamask 5030 3mils dry film solder mask
• Laminator
• Stick tape
• some paper, a little larger than your PCB.
• knife (I use a scalpel)
• brush
• developing tray
• laser transparency sheets
• laser printer
• super glue
• glass sheet
• 2 x tins of beans (or similar)
• 100ml Deionized water
• 1g of sodium carbonate (soda ash)
• Mixing flask
• 395nm UV light 100W
• UV protective glasses
• Yellow light (I use an LED desk lamp with some yellow film wrapped round it).

• In the KiCad PCB editor plot the back mask to an SVG file. If you are doing a duel sided board then also plot the from mask but as a mirrored image.
• In Inkscape I then assemble the images into the same file being sure to leave plenty of whitespace around them. Now print two copies of the image onto a transparency, I set my printer to transparency as the media.
• Next I use super glue to stick the two images on top of one another being careful to ensure they are aligned and the glue does not get near the image (hence all of the whitespace).
• Now set up a 'darkroom and ensure you are working under yellow light. Here you can unwrap the Dry Film Solder Mask (DFSM) without exposing it.
• Now cut out a section of the DFSM just slightly larger than your PCB. It really helps if your PCB is larger than the etched section then you have some edges to play with.
• The DFSM has two sides a matte side and a shiny side, both are covered with a protective film. First we need to remove the matte film as it is covering the sticky side. Use two pits of tape, one on each side, to separate the film, but do not peel the whole thing off yet!
• Stick the DFSM to your PCB on the 'top' edge of the PCB. By top I mean the end you will feed into the laminator.
• In this step you really need an extra pare of hands but it can be done! Fold the paper over the BCP with the fold at the top end and feed it into a heated laminator keeping a tight grip on the matte film. The idea here is: as the PCB is pulled into the laminator you keep a tight grip on the protective film to stop it going through with the PCB. This has the effect of keeping the DFSM flat and wrinkle free as it goes through the laminator and ensures a good clean adhesion. The paper should be slightly wider than the PCB and the DFSM and is used to prevent the sticky DFSM material from sticking to the heated rollers.
• If you are doing both sides of the PCB repeats steps N to N for the reverse side.
• Now