UV Exposure Box to Etch PCBs

UV Exposure Box to Etch PCBs

I’ve always wanted to etch PCBs at home. For several years I’ve been acquiring the necessary equipment to do so.  I tried doing some boards using the iron-on transfer method with limited success.  I started to think about ways to build a UV box to do the UV film method.

Old Metal File BoxWhile looking around on Craigslist to see if I could find a box that would fit the bill, I happened across this one:  an old file box with drawer and an interlock to keep the drawer closed. The seller only wanted $5 for it.  She asked when I picked it up what I was planning to do with it, and I tried to explain, but I don’t think she really understood.

I started working on it the next day.  The first thing I did was remove the divider inside by breaking the spot welds with a cold chisel.  I then pop-riveted some aluminum angle inside so I had a place to lay in some black acrylic which would be the shelf to hold the UV arrays.  I found a perf board design that was perfect for making a large LED array.  In total, there are 880 UV LED’s and 440 resistors.

I used a bathroom fan timer to control the exposure time, installed an interlock switch so if the lid gets opened while power is on, it kills all power.

I’ve etched quite a few boards so far with it, and it works perfectly.

  • Metal file box from Craigslist for $5.
  • Inside the top.
  • Drawer
  • Power plug with fuse.
  • Timer, power switch, power indicator and UV indicator.
  • Power Light on.
  • Safety Label applied.

Electronics Portion

  • Testing the start of the UV array.
  • Progressing nicely.
  • All light up.
  • Test fitting the array boards in the box.
  • Current draw from one fully populated array.
  • Both arrays completed.
  • Timer and small board for current limiting resistors for the LED's.
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