Fred_Fred asked to see the method I use to make my boards.
Here is the technique I use to make them:
First, you need a few basic supplies.
Positive resist copper clad board
Positive developer solution
Exposure light (I built my own)
Laser or inkjet printer (pick transparency film compatible with your printer)
Plastic trays to develop and etch in
One or two pieces of glass of plastic sheet (I use two sheets of glass I cut from an old window)
I also have a couple of optional items that make my life easier:
A small Drill Press and a Tile Saw.
First, I like to cut my boards to size:
The photo sensitive board has a protective white coating. Make sure when you are cutting
that the blade cuts down into this layer and not up through it.
Next, prepare your transparency:
You can print more than one on a sheet to save money, transparency film is not cheap.
The good thing is you can use them over and over. I like to cut them so they are
just a bit bigger than the board.
Now, you can take the board that you previously cut to size and remove the protective coating.
Line the transparency up with the board and set your glass on top of it. The glass keeps the
transparency flat and in close contact with the board. This is very important!
The side of the transparency that you printed on goes closest to the board.
Now you can expose your board to UV light.
My exposure time is about 13 or 14 minutes.
As soon as you are done, plop the board into the positive board developer.
I use a cheap foam brush to gently wipe back and forth across the board
to help the process along. It should take two to three minutes to remove the
exposed etch resist. If it takes longer than this your exposure time is too short.
Here is the result:
Now they are ready for the copper etchant. I use the same foam brush technique here too.
Here are the boards etched and drilled:
You can clean the resist off when you are done with alcohol or you can leave it on. You can solder right through it.
Good luck with your boards!