Homebrew PCBs

It might be worth printing say two of film, fix them together to 
hopefully make the black traces and fills more dense, and exposing 
through that. Registration will need to be watched but should be manageable.

Bill

On 22/02/2012 1:27 PM, tda7000 wrote:
> Recently I had my first try at a UV-exposed board
>
> (because I have nightmares from trying to align paper properly for a double-sided board with the laminator, ha ha)
>
>
> I used this photoresist film: http://www.ebay.com/itm/10pcs-Dry-Film-Photoresist-Sheets-for-DIY-PCB-6x8-q-/320735055777 which worked pretty nicely, although it took me a couple of goes to get it on the copper without bubbles!
>
> Some UV LEDs on a sheet of protoboard for the exposure lamp, and to test out different spacings etc (Thanks to Chris for the LEDs!) - hopefully I can make a proper exposure box once (if?) I get the other issues sorted.
>
> I used my Canon iP2000 inkjet printer and inkjet transparency sheets to make the transparency, unfortunately it did not come out as good as I had hoped, as solid black fills had many quite light parts in them when held up to the light, and when exposed left a speckled pattern on the developed board.
>
> I used a solution of Sodium Carbonate (Washing Soda) to do developing.
>
> Today I tried with a Laser printer but again, holding the transparency up to the light I see too many light areas. I haven't tried exposing using that printout but I feel it will have a similar problem to the previous one.
>
>
> What does everyone else do to get their printouts opaque enough for the UV process?
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>



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