There are two methods of making your printed circuit board. One is the use of a positive resist chemical and by simply masking the pattern where the copper tracks are meant to be. Tracks could be drawn directly on the tape. Using a paper cutter, remove the excess tape to expose the wash away surfaces.
Etching. The two suitable etchants are ferric chloride and ammonium sulfate.
When ferric chloride is used, an ideal etching method for one or two circuit boards is as follows: Use a small shallow plastic or Styrofoam tray. Place the circuit board with the pattern side up and pour the etching solution just enough to submerge the boards. Constant agitation is essential; brush off the surface periodically to remove washed copper surface. A fresh solution should etch completely in ten to twenty minutes. Used solution will etch extremely slowly, especially when cold. Scrub the laminate thoroughly with a cleanser, using a new scrubbing pad to have a clean, shiny, oil-free surface for better adhesion of the solder.
Safety Precautions
1. Exercise caution when using all chemicals. Avoid spilling or splashing the etchant. If any is spilled or splashed, immediately wash the affected areas with water.
2. When etching is completed, wash the laminate by using running water; then, strip off the masking tape.
3. Do not use metal trays as the solution is highly corrosive. Wear appropriate protective clothing. The chemical will permanently stain your clothes. On no account should you use for preparing or eating food any utensils which have been used with chmicals. For good results, practice good housekeeping.
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