Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
>
> Ok I have had enough tonight of TT
> 
> 
> I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
> pic and some transistors)
> 
> I can buy the developer for £1.20, I can get a 8*4 board for £1.20, so
> for £3.60 I can get everything, except a source of UV..........
> 
> I have heard that outside in sunlight can work, any truth in this?
> anyone else do this?
> 
> I have never done UV before, so have no idea on where to go with
> exposure times etc.
> 
> I happen to have a 9w UV light on the garden pond to kill algae, can
> that be used (badly!)
> 
> 
> 
> 
> -- 
> 
> Lez
>



Mercury vapor bulbs will work the best and give the fastest exposure.
Another way is to get a cheap 500 watt quartz halogen work lamp and
use it for UV exposure. They cost about $8 to $10 USD. May work even
faster if you remove any glass filter lens as this may block some of
the UV. I tried it once and it took 2 minutes at a distance of one
foot. The etching resist was negative acting dry film. Positive resist
will take much longer.