Re: Printed Circuit Board Supplies

>From: hansw <hansw@...>
>
>the same boards today are over $133 ! close to double price in 9
>months...
>
>I looking for a different source, any recommendation, in the USA...

Before I gave up trying to run a circuit shop in a "Green" community, I
built them. I used screening techniques to do production, but I used
photosensitized boards to do prototypes.

I sensitized them with photosensitive polymers. They are available in both
positive and negative working chemistries. The only real trick is to get
the boars very clean. Water must sheet over it, not stand in drops. You
can pour the sensitizer over the board in ordinary room light. I prefered
incandescent to flourescent because flourescent contains a lot more UV.

The boards don't become light sensitive till they dry. You can stand the
board on edge (in a dark place) and let the excess drain off, or you can
spin it. The polymer that drains off can be reused, though you may want to
filter it first. I learned to clean the boards so well that reuse didn't
require filtering.

The polymers are hardened by UV light so you can work them with a yellow
safe light. You can expose them with sunlight if you don't have a good UV
lamp source.

Having said al that, I must add that I would never use a chemical process
again. The paranoia of experience compels me to point out the legal danger
you face when using chemicals. Technical illiterates saving their planet
will make your life very difficult. I would route boards today, not
because it is a good way to make a board, but because you could easily end
up in jail using rather common and relatively innocuous reagents.

Ted