Building an Electro-Etching Unit

Instructions for connecting the wires

1. Connect the following three wires using a twist on wire connector:
   1. The green wire from the power cord (this is the ground wire)
   2. The transformer wire #2 (see transformer diagram)
   3. The transformer wire G that was connected to the transformer’s little tab (see transformer diagram)
        

2. Connect the following two wires using a twist on wire connector:
   1. The black wire from the power cord
   2. The end wire on the fuse holder  
      
      

3. Connect the following two wires using a twist on wire connector:
   1. The middle wire on the fuse holder
   2. Wire #1 on the ‘On-Off’ switch
        

4. Connect the following three wires using a twist on wire connector:
   1. Wire #4 on the ‘On-Off’ switch
   2. Either one of the lamp wires
   3. The transformer wire #4 (see transformer diagram)  
      
      

5. Connect the following three wires using a twist on wire connector:
   1. The other lamp wire
   2. The transformer wire #5 (see transformer diagram)
   3. The white wire from the power cord  
      
      

6. Connect the following two wires using a twist on wire connector:
   1. The red banana jack wire
   2. Wire #2 on the ‘On-Off-On’ switch (DPDT) 
      
      

7. Connect the following two wires using a twist on wire connector:
   1. The black banana jack wire
   2. Wire #5 on the ‘On-Off-On’ switch (DPDT)  
      
      

8. Connect the following two wires using a twist on wire connector:
   1. Wire #1 on the ‘On-Off-On’ switch (DPDT)
   2. Wire #3 on the bridge rectifier (see bridge rectifier diagram)  
      
      

9. Connect the following two wires using a twist on wire connector:
   1. Wire #4 on the ‘On-Off-On’ switch (DPDT)
   2. Wire #2 on the bridge rectifier (see bridge rectifier diagram)
      
      

10. Connect the following three wires using a twist on wire connector:
    1. Wire #3 on the ‘On-Off-On’ switch (DPDT)
    2. Wire #1 on the bridge rectifier (see bridge rectifier diagram)
    3. Wire #1 on the transformer (see transformer diagram)
       
       

11. Connect the following three wires using a twist on wire connector:
    1. Wire #6 on the ‘On-Off-On’ switch (DPDT)
    2. Wire #4 on the bridge rectifier (see bridge rectifier diagram)
    3. Wire #3 on the transformer (see transformer diagram)

Now it’s time to turn our attention to making the leads that go from the etching unit to the blade and etching pad. Take a red and a black wire and strip the ends off each. The wires should be around two or so feet to give you room to work. The black lead is pretty easy to make. Just connect one end to the black banana plug and the other end to the alligator clip. Both of these connections should not have to be soldered unless the manufacture has changed their design after the writing of this tutorial.

To make the red lead, solder the red wire to the piece of stainless steel. It would take forever to get the stainless hot enough for the solder to stick to it if you are using your solder iron, so instead use a propane torch to solder this part. Take the stainless and place it on a brick or something. Place some flux in the center and heat it up. When the flux starts to bubble, put some solder into the flame. The solder will immediately melt and form a large bead on the stainless. As the stainless heats up, the bead will start to smooth out. When you see this happen, remove the flame, stick the end of the red wire into the solder, and hold it there until the solder gets hard. It will take a while for the stainless steel and solder to cool. After the stainless has cooled, drill a 1/8” hole through the block, and run the red wire through the hole. Attach the stainless to the wood block with a piece of double sided foam tape on each side of the wire. Connect the red banana plug to the other end of the wire and you are finished building the leads.

All that’s left to do now is to attach a piece of felt over the stainless plate and secure it around the wood with a rubber band. Plug the leads into the box and you have yourself an electro-etching unit.

I hope you have enjoyed this tutorial. If you have any comments or questions, feel free to email me. Thanks again to Bob Warner for making the original information on building an electro-etching unit available.

Chris Crawford
August 2003