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HowTo: How to photo etch a PCB
( Russell Watson)
Step 6 : Exposing the board
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| | I used a 48” florescent shop light with ‘Day Light’ florescent tubes in it for the exposure stage. Set the shop light up 5 inches from the top of the board. I used 2” by 4” and some other sized blocking for this.
Working in safe light, gently peel off the white coating. Don’t touch the green photo resist. Put it under the florescent light, which is not yet ON. I put the PCB board on top of a piece of melamine board so I could move it around under the light (take account 5” top of the board adjust if necessary). Take your transparence, lay it printed side down. Now your reference word will be the right way around. Take the piece of glass or clear plastic and lay it on top of the transparency making sure everything is lined up the way you want it. If so, turn on the florescent light for ten minutes to expose the board. It is better to overexpose than to under expose. I did it for 12 min. 30 sec. Turn off the florescent light; remove glass weight and transparence (still in safe light).
(This picture was taken during the process).
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