Homebrew PCBs

> derekhawkins wrote:
>
> I can do less tortuous 5/5 or 4/4 rules
> (to the limit of the printer) to debunk
> the etching myth as well. How about .003"
> or .002" lines with .005" or .004"
> spacing? What will it take to convince
> you that etching should be the least of
> your worries provided you know what 
> you're doing? Do I have to walk on water?

Derek,

I can print and etch much smaller than 8/8
in a small area of PCB but uneven etching
kills me.  The laser print-out and the
resist on the copper board are all perfect
before the etch.

I have a Kinsten bubble etcher similar to
the ET-10 bubble etcher mentioned recently.

When it is running it creates a swirl in
the tank.  This swirl makes about 40% of
the left side and 20% of the right side of
the tank etch faster than the center.

If I etch till the center area is good the
sides are over etched.  The tracks are
generally still intact but I don't call it
a success becuase there is no uniformity
and some tracks are getting very thin.

I won't say "I can do 4/4 no problems"
unless I can get 4/4 tracks on any part of
a 300mm x 150mm board looking good while
still having differing levels of copper
density across the board.

I am interested in Adams spray etcher for
this reason.  I did build myself a crude
rotary spray etcher but was too scared to
use it because of the amount of aerosol
it created during the water tests.