Homebrew PCBs

> I've used it quite a bit.  It seems to work well *if* you have a
> vacuum system.  Here are some 5 mil and 3 mil lines exposed with it:
> 
Why do you need a vacuum system? Is this to make sure the mask layer is tightly against the board?

>         http://www.delorie.com/pcb/djspirals/

Those are really very good. I remember using your spirals to check out my 1200dpi laser. I have not had chance to actually generate any etched results. Your 3 mil is very impressive. 

> 
> You are seeing only the visible portion of the spectrum; they radiate
> mostly in the UV.  The spacing was designed to take into account their
> UV pattern.  Plus, I don't recall if that picture was taken before or
> after I went through and aligned all the individual LEDs.
>

I thought the visual light would show something similar to what would be happening with the UV. I have found some superflux UV LEDs that have a viewing angle of 100+ degrees so I was thinking I could make a thinner version and also make two so I could do both sides at once. I did a bit of math and reckon I probably only require the board to be 2cm - 3cm away from the LEDs. I just do not at this moment know how good the intensity will be. I suppose I just have to give it a shot really. 

Trev