What is the Difference between Uncoated Copper Clad boards and Positive Sensitized Copper Clad boards?
Uncoated Copper Clad boards do not have a protective coating on them. When you place them in an etchant bath as they are, all of the copper will come off. The uncoated boards require the use of toner transfer paper. One product would be 182-1003-ND.
A board pattern will be printed on to the transfer paper. The pattern is heated and melted on to the copper board. The transfer paper will protect the copper from coming off the board when it get put into the etchant.
The Positive or negative Sensitized Copper Clad boards will have a coating on them, which is know as Resist. The toner paper is not needed with these boards.