Standard Track and Pad Sizes Etched Board

The pour causing less need of etching is a good (enough) reason to use it. One could actually use less etch bath and stretch out your chemical consumption.

Suggest that you start by doing a test/sample board of about the same dimensions that you envision for the final layout. Do some horizontal, vertical, and 45-deg tracks in a range of size and spacing from, say,

8-8 (.008" tracks, .008" spacing) up to maybe .128". I've done 10-10 with Press'n'Peel but it's nothing I'd ever recommend today. Inspect closely for "mossy" patches bridging between traces and over-etched spots that break or neck-down traces. Warning: it's not likely to be a pretty sight.

No experience with DipTrace (for home/hobby projects I use Kicad, which is FOSS) but if it can't handle a copper pour, throw it out.

For general advice, download and read by the esteemed David L Jones. Also, visit his

Finally, think really hard about getting the board made commercially. You can get a good double-sided board with plated thru holes, solder mask, and silk screen for a ridiculously low cost nowadays. You'll have to wait for a couple or up to a few weeks but you'll be starting with a real PCB. I've used Seeed Studio's Fusion PCB service as well as Sparkfun's old BatchPCB with good results. BatchPCB is now handled by

which is a domestic US fab and has quite reasonable pricing. Haven't used them yet but probably will for the next gadget.

Not sure about toner transfer, for the kinsten photo resist boards I do at home I always make the tracks at least 0.015" minimum and pads

0.075". You can get away with them being thinner/smaller but with my set up these sizes give me a dependable outcome.

I can usually neck tracks down to 0.010" where needed ok.

Bigger pads reduce the chances of problems when drilling, ie kerf/burrs or the pad lifting off the board.

I find my heavy old drill press at 1000+ RPM drills cleaner & better than a Dremel (in a decent stand) running at a higher speed. If you go for carbide drill bits be prepared to break lots of them. HSS bits don't last as long but are cheaper & don't break. Get bits with the 1/8" shank

- much easier to use.

You may already know all the above.... :)

If you're willing to wait a couple of week you can get good quality boards from China in small quantities through SparkFun and other aggregators. It's still $$, but it's a hell of a lot less messing around.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com

As others have said I'd look seriously at getting in done by a board house or the spark fun route. I haven't done etching in .. maybe twenty years. (Double sided is a real pain.) But I'd keep traces as big as possible. The other thing I use to do was use 1/2 oz. copper. That let it etch faster.

George H.

On Fri, 19 Jul 2013 21:35:16 +1000 in sci.electronics.design, snipped-for-privacy@interquest.com wrote,

Eschew proper toner transfer paper. Follow Tom Gootee's methods.

The paper Gootee mentioned is no longer available. Staples help line said a replacement for that paper is item #633215 "Color Laser Paper gloss finish - heavyweight".

Ed