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I'd like to buy or build a UV exposure unit for the photoresist method of making my own PCBs.

Nice-to-haves:

  • adjustable timer knob
  • works for double-sided PCBs
  • US$50 budget

What are my options?

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Making one for $50 with those features is going to be difficult. Here is my very simple one:

Here

It's made from MDF and some strips of wood, held together with some glue and wood screws. A sheet of ordinary window glass rests on the upper wood strips.

I used standard 12" fluorescent light fittings, disassembled, with the tubes replaced by UV tubes. They are connected to a piece of mains cable and a mains plug.

I time the exposure (11 minutes) with the kitchen timer on my Dell Streak tablet. Although it's very crude, I get excellent results - 8/8 mil tracks if necessary - with transparencies printed on my cheap inkjet printer.

It cost me the equivalent of about $40.

You could build a basic unit like mine, and add the bells and whistles later.

Some members of the Homebrew PCB Yahoo group are using UV LEDs, but they are far more expensive than a couple of UV tubes. Enough LEDs for a small board could cost over $100, IIRC.

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  • \$\begingroup\$ Do you have time to describe the circuit? I'm new to fluorescent lamps. \$\endgroup\$ – Isaac Sutherland May 4 '11 at 19:08
  • \$\begingroup\$ It's quite obvious if you buy standard 12" fluorescent light fittings. The ballasts should have the connections on them. \$\endgroup\$ – Leon Heller May 4 '11 at 19:24

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