[sdiy] drilling pcb boards...sore throat

[Jason Tribbeck]

Hi,

> The cost of making your own (one-off) boards is minimal, once you've
"tooled
> up".  This means having some kind of layout software (typically free
over
> the web, although I do my layouts by hand in Excel because it's more
fun,

Excel!??! (I'm guessing you mean Eagle).

> and forces me to get up close and personal with the circuits), some
etching
> chemicals (pool acid and household hydrogen peroxide in a glass dish
covers
> it), access to a small drill press with some tiny drill bits, a
laserjet
> printer and a household iron.  Once all that is taken care of, the
blank
> boards and the transfer paper each cost about $1 to $2 per project,
> depending on how conservative you are with them.  Assuming you've
already
> got an iron and a laserjet printer, the drill press is paid for with
about 4
> handmade boards.

I'm getting a lot of success with an inkjet printer, and (fairly
ordinary) OHP inkjet sheets. I was looking at using some proper drafting
film, but that ran to about $3 a sheet; I bought 100 sheets of OHP
inkjet paper for about the same (not a huge amount to throw away if it
didn't work) and experimented with the settings.

It's not completely opaque, but it seems to work well (~0.006" lines do
appear [I wouldn't trust it to run signals down]; 0.016" is what I'd
normally use, spaced 0.025" apart - leaving 0.009" separation). The only
problems I've had are where the edges of the board aren't flat, and
pushed the film away (I ordinarily file the edges down; just forgot to
do that the last time). Recently, I've done an SMT PIC18F8585 (0.02"
spacing) with no hassles (even soldering it wasn't terribly difficult).

I've not actually used any prototyping boards for a long time now;
making PCBs is just quicker for me - although I really hate drilling the
holes.
-- 
Jason Tribbeck