Now it is time to repair the aluminum panel. First step is cleaning the panel with a fine sandpaper. All color coating needs to be removed.

After, the mask needs to be ready by adobe illustrator design suit or other relevant software. Below is the designed masks for lithography. The old panels were scanned by a ubiquitous scanner and redesigned as the original shape maintaining the dimension.

Now it is time to put a photo sensitive laminate on the panels for lithography. They are mainly in use for PCB manufacturing at home or for hobby applications. It is kept in a black housing to block the ambient light. It is said that they can withstand in the low light room. Anyway I don’t take risks and use my hand-made deep red lighting to ensure that there there is no damage to the photo sensitive film.

Well, the masks are ready, so are the panels. After peeling off the removable layer on laminate, it can stick to any flat surface. At this step no air bubble must be entrapped between laminate and panel. I used a hand roller to purge air bubbles out. Below is the finished laminated panel.

Now it is time to expose to UV light to transfer the patterns on the panel. I used a piece of flat window glass to press the panel on the surface of UV light bed. The mask which is already at hand needs to be put on the laminated panel. Care should be taken to flip the mask, otherwise the wrong lithography will be done.

I put the whole panel and mask on the flat surface of the UV light bed. The UV light bed is hand-made too. It is made from UV oval LEDs to emit UV light. After several minutes of high exposure to UV light, the laminate is ready for next step: etching in chemical bath.

The exposed film must be immersed in sodium bicarbonate aqueous solution for several minutes to develop the photo sensitive layer. Then it needs to be washed out by water to remove the parts which are not exposed to light (the black pattern).

The panel is now ready to mount on voltmeter. The laminate after exposure seems purple and removed pattern denotes the pristine aluminum color.