Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
11/01/05 02:02
Read: times


 
#103208 - Q&A double sided etching
Responding to: ???'s previous message
Hello Vignesh,

1. How to home-make thru holes? Soldering a pin between top and bottom layer to simulate Plated thru hole? how do you do them?

Ans. I solder a pin between top and bottom. This can be done easily when you first start to build the board. Put a couple of coins under the board to raise it about 1/16 inch from a flat surface. Insert the wires and cut off about 1/16 above the board. Do this for all the feed thru and then solder in mass. Flip the board over and solder the other side making sure coins raise the PCB. Once you get the hang of it you can do a lot in a short period of time.

2. What is the etchant do you use? FeCl2 or Ammonium persulphate?

ans. FeCI2. Can't ship Ammonium persulphate into Hawaii via air.

3. Do you etch both sides simultaneously or single side at a time? Because, I usually etch single side by shaking it within a tray of Ferric Chloride etchant, with the copper side up. If I put upside down the PCB, then the toner gets knocked off and tracks get etched away.
Since double sided boards have toner on both sides, how do you do?

Ans. I etch one side at a time. For the other side I protect it by putting shipping tape over it. Four or five passes gives me (2 inches wide * 4 = 8 inches of protected area. I use a flat file to get rid of the tape rough edges. Very quick and dirty way but extremely good way to protect the other side of PCB. I then make a handle using shipping tape (example tape handle folding ___|___) and put on the top of the board. This allows me to drop/raise the PCB onto/from the top of the acid under control conditions (the PCB floats on the acid). This is an important step.

Once one side is etched I then drill the holes and do the other side. Aligning the pattern to the other side is easy and you can get it to a Nat's ass of being on target if you do it right. Its really simple. Just push pins thru outermost edges (four total) and position over the PCB. Use very little glue (I use a glue stick) on four ends to hold pattern in place. Remove one pin at a time flatting down the pattern. Once done it will stay put with rough treatment.

For tinning I use a solder pot and solder. Any square metal pan will work. I use a propane burner to melt the solder. Takes only about two minutes to go from solid to liquid. Then reduce the flame enough to keep the solder a liquid until I am done. Sand the PCB foil pattern and drop in solder. I use an air hose (hooked up to a small air compressor) to remove any solder blocking holes.

Regards,

Charles Bannister


List of 25 messages in thread
TopicAuthorDate
Toner Transfer PCB's            01/01/70 00:00      
   Toner Transfer            01/01/70 00:00      
      Don't forget            01/01/70 00:00      
         I used acetone            01/01/70 00:00      
         clean copper side            01/01/70 00:00      
   File Edges of PCB top and bottom.            01/01/70 00:00      
      Type of paper used            01/01/70 00:00      
         PNP BLUE Type thermal paper.            01/01/70 00:00      
      Amazing            01/01/70 00:00      
         Double sided...            01/01/70 00:00      
         Alignment of Top and Bottom PCB Layers            01/01/70 00:00      
            Double sided etching            01/01/70 00:00      
               Double sided post !            01/01/70 00:00      
               Q&A double sided etching            01/01/70 00:00      
                  Bubble tank            01/01/70 00:00      
                     Making one with these guidelines            01/01/70 00:00      
                     addendum            01/01/70 00:00      
                     Like these...            01/01/70 00:00      
                     Something like this?            01/01/70 00:00      
                        Yes            01/01/70 00:00      
                  New methods            01/01/70 00:00      
         Art Paper            01/01/70 00:00      
            Blue sheet Vs Photographic paper            01/01/70 00:00      
            Timing and Tinning            01/01/70 00:00      
               Tin your self            01/01/70 00:00      

Back to Subject List