ETCHING THE 
P.C. BOARD
Etching the board is a process which requires patience.  Although the process may take a while to complete, the result of having a professional looking board is well worth the time.
The etching process described here is the easiest, most common, and least expensive method.  The etching chemical used is called ferric chloride (see Step 1 for an explanation of how this chemical works).  Although there are methods and chemicals that provide for a faster etch, ferric chloride is a great choice for beginners and those who infrequently make p.c. boards.

Step 1: Gather Materials
 
 








Safety glasses. It's a good idea to wear these at all times while working with the etchant.
Gloves.  Because the etchant is a mild acid, it is an excellent practice to wear gloves at all times when handling the etchant: from pouring the acid into the etching tray, to working with the board, to cleanup.
Plastic dropcloth.  This protects the working surface from the acid - important since it stains everything permanently.  A plastic trash bag can be used here.
Etching tray.  The etching tray provides a convenient container to process the board.  If you purchased a kit, this is the container for that kit.
Ferric Chloride.  This is the etchant - what actually makes the circuitry.  Ferric Chloride is a mild acid and will permanently stain anything it comes in contact with (clothing, etc).  It will also discolor your skin and may give you an acid burn.  Here's how it works: The acid weakens the exposed metal (copper) of the p.c. board and literally eats it away.  Registering the board prevents the acid from eating away at the copper, thus leaving the copper traces ready for you to drill the board and insert the components.  Ferric Chloride works best and fastest when it is hot - above 100F.  See Step 2 if you have a dry powder and need to mix the etchant.
Heat Lamp.  Aids in heating the acid to above 100F.
Scouring Pad.  This comes in handy after you have etched the board.

In addition to those materials pictured, it is suggested that you have:
Stirring Stick. Stirring the etchant helps to reduce etching time.
Jar of Water. Helps to clean the etchant from the board and loosen the tape.
 
 

Step 2: Set-up Materials

Select a clean, level surface to work.  This area must have good ventilation because the heated acid gives off some fumes.  If you have purchased the dry powder etchant, follow these directions:

Arrange your supplies neatly on the plastic drop cloth.  Very carefully pour the acid into the etching tray to a depth of between 1/4-inch and 1/2-inch.  This is about the minimum depth to produce adequate etching.  Set up the heat lamp approximately six to eight inches above the tray.  In about three minutes the acid is up to temperature and you're ready to start etching!
 
 

Step 3: Etch!
 
 








This step requires patience and good timing in deciding when to remove your board.  After you make your first board, you'll know exactly what "clues" to look for.
Once the etchant is hot - and remembering gloves and glasses - place the board into the bath as shown above.  Use the stirring device you selected to stir the acid frequently (every 30 seconds or so).  Stirring drastically reduces the time it takes to etch the board.
After about 10 minutes, check the progress of the board.  The etching should be noticeable at this point–especially at the edges of the board.  The copper that is getting etched will turn in color to almost pink.  Once the edges are noticeably etched, check the board more and more frequently.  After about 5-10 minutes longer the board should be nearly complete.  It is important not to go too long because you can actually start etching the copper out from under the taped traces!  Don't worry if the board is taking 30 minutes or more to completely etch.  If your board is relatively small, try stirring the etchant more frequently.
When the etching has been completed you should not see any exposed copper on the board.  Only the taped traces should remain.  If you still see a small amount of copper on the board, go ahead and etch it off but BE CAREFUL not to etch too long and undercut the traces.  Move on to Step 4 when you are satisfied with the appearance of your board.
 
 

Step 4: Clean the Board

For this step you will need the scouring pad and the jar of water.
Remove the board from the acid bath and place it into the jar of water to wash off the ferric chloride.  Once the board has been washed, use a dampened scouring pad to remove all the traces from the board.  The taped tracks can usually be peeled off or scraped off by hand, but the rub-on dry transfer patterns are easier to remove with the pad.  The scouring pad also helps to clean the board and the traces after the etching process.
 
 
 
 
 

Congratulations!  You have just etched a professional looking p.c. board!  Now dry the board well and let's view the finished board which is now ready for drilling....
 
 

Finished Board!
 
 

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