Re: Type of Circuit Board for Etching?
1. the print transfer method is cheap and simple but can be difficult to get good results, the print can only be used once. It is not used commercially because it rarely gives consistent results and doesn't lend itself to volume production.
2. It depends on the PCB you want to make:
Single sided means it only has copper on one side, the other is plain fiberglass or cardboard.
Double sided is the same but has copper on both sides.
Pre-sensitized board is available single and double sided but has a special photographic paint covering the copper, you need it if you use a UV light source and resist image.
If the PCB design is simple, you could also consider directly drawing on the board with waterproof ink. The ink will protect the copper it covers from being dissolved by ferric chloride etchant. Obviously, that method is difficult if you want to make several identical copies.
Personally, I use the re-sensitized board and prepare the mask on overhead projector transparency film. You print or copy the original track layout on to the film then lay it over the paint layer of the board then expose it for about 4 minutes to a UV light source. The printed tracks on the film works like a sun shade, it stops the UV reaching the paint, where UV gets through the paint changes chemically so it can be wiped away with developer solution. You are left with an image of the PCB tracks painted on bare copper so when you etch it, the bare areas are dissolved away and the painted areas are left intact. You can get consistent results using this method and it's easy to make tracks as narrow as about 0.2mm, the artwork can be used over and over again too!
Double sided boards are much harder to make so I don't recommend you start with them. The production principle is the same but it is difficult to align the two sides accurately.
Brian.