Homebrew_PCBs

If I build a box with four fixtures and put in them black light bulbs and wire them to the other parts with a piece of glass 10cm above the bulbs what happens 

Yes, the top should be opaque. It doesn't have to be glass. I had a piece of wood with a sheet of glass on a hinge.

Anything black will work. It is however so much easier to do both sides at once. I went to home depot and bought 2 black light tubes and a single ballast that runs 2 tubes. Made a 2 quick wooden boxes with a glass pane on one face. I lined the boxes with tinfoil to reflect as much light as possible. Then I used connectors directly to the tube pins to wire the tubes and ballast together. The 2 boxes have a couple of feet of wire between them so I can move the top box around. Then to do both sides at once. I print off both images and hold them together up to light so I can see through them. Then staple the 2 sheets together on 3 sides. Then its just a mater of slipping the board between the images, dropping them on the bottom box and placing the top box on top.  Flicking on the power and watching the clock. Always comes out perfect with perfect alignment. You could use 2 similar sized cardboard boxes instead of wooden boxes to make things simpler.

Thank you but I will cover the top board in black like I saw on a video.

Thanks that is what I assumed after watching a U-Tube video with two color bulbs. One a bug light in a darkened room, the second a black light bulb

Very good I already have four or five fixtures laying around so all I need

On 29/03/2014 07:22, kbyrne10@... wrote:

> Very good I already have four or five fixtures laying around so all I need
>
> is black light bulbs. How much time under lights if bulbs are 10cm away
> from the glass if I may ask?

It depends on the UV lamps, you need to calibrate it with test strips.

I use 11 minutes with two UV tubes and about 20 cm.

Leon
--
Leon Heller
G1HSM

similar set up and 11 to 12 mis is good. I have even used 13 mins on boards with large ground planes and the boards develop very quickly while leaving the resist totally untouched where needed.