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HowTo: How to photo etch a PCB
( Russell Watson)
Step 9 : Etching the board
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| | Still working in safe light, drill a hole in a corner of the board where nothing is there. Place a piece of string, fish line, (I used weed eater line) through the hole so you have something to pull the board out of the etch ant with. Place the board in the etch ant for 5-30 mins. Depending if you have a heater on and bubbles going. I heated the etch ant to 42 C or 108 F with air bubbles and took 11mins. to etch the board. I started checking at 4 mins. and noticed that the top of the board was etching quicker than the bottom, so I turned the board around. When finished, take the board out and put in water. I had 2 buckets to check the board during the etching stage and one clean bucket of water for it to sit in while I cleaned up. CLEAN UP TIME!
Ferric chloride is able to be heated no higher than 57 C or 135 F. An ideal etching temperature is 50 C or 120 F. I could not go that high because the fish tank thermometer I used did not go that high. I am going have to find one that does.
This is a homemade etching tank made from acrylic plastic. It holds 1 liter or 32 OZ of etch ant nicely. Here is a ‘how-to’ that I found www.embeddedtronics.com/etchant.html. I don’t recommend building one, just get 1 gallon of etch ant and a 1 gallon rubber made container. If you do decide to make one, notice the big rubber made container that the pump is sitting on. Place the tank in one of those when etching in case the tank leaks or ruptures. Use proper acrylic glue not just silicon like they recommend.
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