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1) I start by drawing the circuit with Paintshop Pro. I set the resolution to the highest my inkjet will go, 600dpi in my case. To make it easier I set the grid guide and rulers to .1" (common distance between ic pins) so whatever I draw will printout exactly the right measurements. Try a test to make sure. It's easier to draw it looking from the topside down and reverse-image it when your done.
2) Get some good quality transparent film sheets and print your design at the highest quality COLOR settings even though you're only using black ink. That is the key to getting a crisp solid print. Let it dry before touching.
For the next steps I use MG Chemicals Positive coated circuit boards & chemicals. Be Sure To Use A Spare Or Scrap Piece To Do A Dry Run Test First!
3) In low light peel the protective layer off a MG Chemicals 600 series board and place it face up on a flat surface. Position your transparency carefully on top of the board & a sheet of glass from a picture frame over that. Prop on books, two 18" flourescent blacklights 9" obove your artwork. turn on the lights and expose for 4 minutes. then put in dark place till ready for next step.
4) Developing Process:
A) Mix 1 Part Developer (MG Chemicals) to 16 Parts Water (Example- 1 Ounce Developer to 16 Ounces Water) in Rectangular Glass Baking Pan (Stir Well!)
B) Submerge Board and Brush Continually With Wide Foam Brush Using Slow Light Sweeps.
C) Process is Complete When Every Hint of Green is Gone From Between all Lines and Empty Areas and Design Appears Very Sharply Defined (Usually Less Than 2 Minutes).
D) Rinse Thouroughly With Water and Pat Dry With Soft Cloth.
E) Board is Ready For Etching.
5) Etching the board. I use radioshack etchant heated by putting open bottle in a pan of boiled water taken off the stove for about 15 minutes. Pour the heated etchant in a glass baking pan & then immerse the board and continually agitate the pan or board till all unwanted copper is removed.
I used to do it the way Promocom described, but then I discovered the TTS from Pulsar (http://www.pulsar.gs) which really cuts down the production of a PCB down to a minimum.
TTS=Toner Transfer System, paper with a special coating that you print onto using a toner based device (laser printer, photocopier) as a mirror print, then thermally transfer using an iron or a laminator (Pulsar also sells modified laminator for this purpose).
Etching, I used to try all sorts of things, "baths and tubs" warm and cold, with bubbles and without. Heck I used to use Chloric Acid and Hydorgen Peroxide mixture at one time because I couldnt get Ferric Chloride and shake the dish, wait for hours sometimes. But then I learned something (from Pulsar's website again) that have radically changed the way I make PCBs nowdays.
Don't bother heating the ethcant, shaking the dish or adding an air pump and making a complex bath. All you really need is a pair of rubber gloves, shallow dish and a soft sponge. I couldn't believe it until I've tried it (I guess the electronics vet from Pulsar has figured this out long ago and kindely shared his find).
Just place the PCB into a dish, pour some etchant and gently rub with a corner of the sponge. There's absolutely no simpler and faster way to etch a board than this. Basically within minutes the board will etch, and I don't want to sound like a commerical but try it and hold your jaw before it drops (oh don't touch your jaw with the glove that was in the ethcant)
There's no developing, no hassle, not many chemicals (except etchant and the nail polish remover). Ideally you should have a laser printer and this modified laminator and there will be no end to joy.
Of course you can always get away with a photocopy of a PCB layout and an iron but need to be careful with an iron not to over or under do it.
Afterwards, drilling with a Dremel or any modeler drill on a stand, and off you go to soldering and hopefully testing the circuit...