UV light method, PCB making
This is the only tecnique ive tried until today and if you have the proper equipment you can have some really good results. You will need the Following :
UV-sensitive PCB, there are two ways, you can buy a can of spray positiv 20, and gently spray it on an empty copper board after you have washed it and scrape it with sandpaper, after that you need to let it dry under a heater for +/- half an hour, this is the cheapest method but its a lot of work and you really need to perfect your technique.
The second way is to buy it on the shop ready, this is specially much more preferable then to make it yourself, if you are making a double sided PCB. They came with a sticker to protect it from the light and you just have to peel it just before using it.
UV light box, while there are many tutorials on the internet and its not complicated to build one im using a borrowed one from work, the only bad thing about it is only one side, meaning it only has UV bolbs on one side of the box, so for double sided pcb's i have to run it twice, one for top and then bottom, this can be problematic with alignments.
Natriumpersulfat or iron perchlorate, ive been using for many years iron perchlorate and only recently ive used natriumpersulfat and i was happy with it, it does everything the other one does with the advantage that it is colorless at the begining but it gets blueish after, still the advantage is that you see better the progress of the pcb without having to take it of the tank. Iron perchlorate is yellow all the time it just gets darker with time, wich makes it more dificult to see the board inside the tank.
Etching tank is one of the final steps, you can see my etching tank here.
Printing paper, i have been using some inkjet film, and this is one of the most important steps, to get a good printing, a good printer printing as black as possible is vital. I still havent found the ideal paper and printer, therefore i usually have to do some of fixing on the final pcb.
PCB developer can be found on online shops like farnell or elfa, or of corse your local electronics shop, it is used to remove the unecessary remaining burned sensitive layer on the pcb, after the exposure.
Let's start :
First we need to print our circuit, onto the paper, im doing a double sided board here, the good thing about this paper film is that you dont need to mirror the bottom, just print top and bottom on the same side of the paper film.
If you notice the distance that is because im gona cut it in the middle and i need some space, then i align them perfectly and put some glue between the papers.
We can now peel of the PCB, put it between the papers and insert it inside the UV box for 5 minutes each side, be very carefull when turning the board, any small shift on the board will cause bottom and top to unalign.
Now the light burned the protective layer on the copper and we need to get rid of the layer we dont need, for that we use the pcb developer gently with a pencil.
After this just put it straght inside the etching tank, and let it work, for a board this size it usually takes 35 minutes, and that because my bubbles are weak, i need to buy a better motor.
You can now clean it and srap it with a scoth britz sponge to take out the remaining protective layer.
We need to finalize it by drilling vias and thru-holes, and our PCB is now complete to start soldering.
I hope this helps someone :)