How to make a printed circuit board (PCB) using the UV light LED method.

Step 4 Prepare the developer solution.

Prepare the MG Chemical developer solution with 1 part developer, 10 parts tap water. I used 1/4 cup developer, 2 1/2 cups of tap water. Be sure to mix the solution with tap water thoroughly before placing the PCB in the solution, otherwise the photoresist will be eaten away in undesired spots.

Place the PCB in the mixed solution and shake it around face up. The parts where the photoresist was exposed to UV light will be washed away in about 5-10 seconds. Do not leave the board in the developer solution for too long, otherwise all the photoresist will be washed away. Place the PCB in cold water immediately to stop the reaction once the board is finished.

The developer solution can be re-used for multiple PCBs.

Note: The solution is dangerous to skin and eyes. We suggest wearing gloves and goggles.

Note: We tried all sorts of chemicals to eat away at the photoresist. We found that the MG Chemical brand developer worked the best. You could also try using Sodium Hydroxide (Lye from Ace Hardware) but you will have to experiment with what % to put in tap water. The percentage of Sodium Hydroxide to tap water is important because too strong of a solution will wash away your non-exposed UV photoresist.