Homebrew PCBs

scratch_6057 wrote:
> Could those of you who are using Dry Film Photoresist 
> please give any recommendations as to what you are 
> using, results, and sources for small quanity supplies in 
> the states? 
> 
> I have a Xerox 9" Laminator that I have successfully
> Passed 0.060 board thru, so that's not a problem.
> Markings on the temperature controller go up to 
> 125C / 257F. 
> 
> I am aware of "Think N Tinker" and "Micro-Mark"
> in addition I have found quite a few suppliers of 
> Dry Film Photoresist for "Intaglio" (SP?) print plate
> making.
> 
> It looks as if what I've found so far is "Negative Acting"
> and if I'm thinking correctly then a transparency for that
> would require a LOT of ink / toner?  
> Any "Positive Acting" resist films available?
> 
> Looking to laminate my own FR4 board and probably do some 
> etching of Brass  / Copper sheet.

I get a panel of precoated double-sided negative pcb from my
pcb vendor for only 10-20% of the price in electronics shops.
I keep it in the fridge, and it's usually 2 or more years before
i use it all.

I expose it in a homemade uv lightbox for 90secs. It has a 150W
HID globe 60cm from the pcb and in a parabolic reflector.

I use a homemade program that reads positive gerbers, makes them
negative, overlays a "dimple" for each hole, and outputs postscript.
Because my boards have lots of groundplane, very little ink is used
and the FeCl etchant lasts atleast a year.