Homebrew PCBs

hmm i heard of this special paper before but it only found it at the electronics shops where it was more 
expensive than copper clad itself. 
i may try it but really no longer want to use photo process.

to plain copier paper i can say exposing works if you use "pausklar" which i guess is some thin oil 
spray (smells like lemons). this makes the paper enough transparent for exposure (prolong time).

regards
st

18.04.2003 01:14:30, "Jan Kok" <kok@...> wrote:

>From: Stefan Trethan
>> The temperature doesn't seem to be a problem. i set the iron to
>> highest on last try and the toner fused well. i maybe didn't soke
>> it enough. but the most problem is i think that my printer puts not
>> enough toner on the paper (also leaving pinholes). i also had this
>> problems with ohp film (and partly because of this want to
>> abandon using phototransfer process).
>
>Laser printing on overhead projector film works very poorly.  The dark parts
>aren't very dark, and if you try to make it darker, the transparent parts
>pick up some toner, and you get pits in your copper traces.  Awful.
>
>I've had much better luck with laser printing on vellum (thin,
>semi-transparent paper, can be bought in artist supplies stores for a few
>cents per sheet).  Put the vellum with the toner side down against a
>photosensitive board and expose to light.  I got excellent results with 12
>mil lines and spaces.  Got poor results with 8 mil lines and spaces (some
>traces came out too thin or broke), but I think some more experimenting
>might produce better results.
>
>I tried printing on ordinary laser printer paper, but it is just too
>opaque - I couldn't get the board to expose.
>
>One other thing to watch for: fluorescent lights change their intensity as
>they warm up and as they age.  So, if you turn on the light and expose one
>side of the board, then flip it over and expose the other side for the same
>amount of time, the two sides may not be equally exposed.  There is a
>cumulative exposure meter circuit in The Art of Electronics by Horowitz and
>Hill that might help with this.
>
>Cheers,
>- Jan
>
>
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