Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!husc6!cmcl2!rutgers!ucla-cs!ames!think!bloom-beacon!mit-hermes!jpexg From: jpexg@mit-hermes.AI.MIT.EDU (John Purbrick) Newsgroups: sci.electronics,rec.audio,comp.sys.apple Subject: Re: PC board photo etching kits Message-ID: <2868@mit-hermes.AI.MIT.EDU> Date: Sat, 4-Jul-87 22:55:13 EDT Article-I.D.: mit-herm.2868 Posted: Sat Jul 4 22:55:13 1987 Date-Received: Sun, 5-Jul-87 07:43:42 EDT References: <2392@uwmcsd1.UUCP> Organization: MIT AI Lab, Cambridge, MA Lines: 24 Summary: How to make PC boards Xref: mnetor sci.electronics:893 rec.audio:2352 comp.sys.apple:1905 Re how to make usable PC boards: Cleanliness is next to godliness!! Put on rubber gloves. Take the board to a sink (not a heat sink, dolt!) and scrub it with Ajax or a similar abrasive cleaner. Get it so that the board has a little "tooth", that is, a uniformly rough surface. It has to be so clean that water won't bead up on it. Then shake off as much water if you can--blasting it with compressed air is better, the idea being to stop the impurities in the water from drying on the surface. Let the board dry in a dust-free location, resting on an edge, not flat. From now on I can only speak of negative resist, but yours should be similar. Handling the board by its edges, pour a uniform coating of resist over it. Tip it back and forth, and let as much of the resist drip off as you can, the idea now being to get a very thin coating. It helps to warm the board (with a heat gun if you have one) as this makes the resist flow better, but use some caution as the resist may well be flammable. Again, dry on edge away from dust. After 24 hours you should be able to use the board. Make sure that your artwork is clamped firmly to its surface. We used a setup of glass sheets on both sides of the board, clamping it with bulldog paper clips--the artwork must be flat! Then expose, develop and etch. The last stages are the easiest.