>The spray you need is named POSITIVE 20 made by KONTAKT CHEMIE has Art. >No. 20.820.6.04.25.02 >I got my last can from the UK, but can't find the source right now. >I used Circuit Specialists for a while until they jacked up the price >too much, then I found > >http://www.oselectronics.com/ose_p78.htm > >6" X 9" double side board for $9.90 > >About the Positive 20: > I used it for many years, the trick is to clean the PCB ONLY with Ajax >powder and water. Make a small paper towel pad, wet it and the board >then apply Ajax powder and rub in small circles. DO NOT use wire wool. >The reason: Ajax powder makes the surface much smoother and when you >spray the Positive 20 on it, the surface tension is far lower and it >allows the Positive 20 to spreads in an even film. ( no need to spin it >and all that other crap... ) >If you use wire wool the Positive 20 will bead and not spread, and after >using wire wool there is NO hope of getting Positive 20 to spread evenly >unless you spin it... and that's a big mess. >Dry it in a dust free environment, you can also speed up drying by >placing in a warm oven. >Positive 20 exposes fine with a Garden Grow Lamp, and develops very well >using household Lye ( I use Red Devil Lye) > >Good luck... >hansw >PS may be some one form UK knows where it can be purchased. www.schuricht.de or www.distrelec.com do have this product. No idea though if they deliver to the US. Worth a try though since they also have an online shop. I haven't followed the thread, but I wonder why one want's to use this spray. I use either pre coated material or then dry film resist, but anyways.... Markus
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Re: [Homebrew_PCBs] Re: Positive resist
2003-07-05 by Markus Zingg
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