Homebrew_PCBs

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:

> With my first board now drilled, and "Detailed", I am quickly
> gaining the appreciation for alternative methods.
>
> I used a riffler file to clean between the traces - worked pretty
> good. It was easier to use than a hobby knife.

You probably didn't leave the board in the etchant long enough. from
looking at the pictures, even with trace spread, there seemed to be
some gap. I usually give my boards a few minutes past where I think
its done. I use AP to etch which is clear and with good lighting in
my vertical etch tank, I can see a lot of detail.

>
> I used a #60 high speed steel drill for the holes. Chucked up real
> short in the drill press chuck (yes I know, your not suppose to
> chuck on the flutes - but it works great). Drilling went real easy
> and the bit did not walk around as I suspected it would.

That's kind of a big bit. I use 64-69, depending on the leads.

>
> There are a number of problems I don't like about the process
> already...
>
> 1) Chemicals - nasty stuff

AP is a lot better than FeCl or CuCl on the nastiness scale. I've
used all 3 and like AP the best, even with the disposal problem.

> 2) Toner transfer & detail - maybe a hit or miss process. Although,
> it it looks bad, you can remove it and try again with no real loss
> at this point

I agree with ST, this will get a lot better with practice. I've
gotten pretty good at it - lots of little tricks to learn. I've been
batting 1000 for that last 5 or so boards.

> 3) Chemical etching appears to be a bit tricky, especially in the
> areas where the traces are tight together. It is hard to see if you
> etched away those areas until you get the board out and cleaned.

as I said above, give it more time. you might also get a loup, pull
the board out, rinse and carefully inspect it. If not done, put it
back into the brew.

> 4) Drilling lot's of tiny holes is very hard on the eyes. I used a
> large magnifier light device to help, but my eyes must be getting
> older than the rest of me :-(

yeah. a cnc driller can help but the best "holes" are the ones you
don't have to drill. I use SMDs where ever I can. My last board had
3 ICs, 30 various other parts and a number of connectors. 26 holes
all together. and my eyes are getting pretty old along with
"floaters" but I manage. good lighting helps there.

> 5) Detailing - cleaning up touching traces. Again, the process is a
> pretty basic mechanical process using: picks, files, and hobby
> knife. Would be pretty easy if I could only see this stuff without
> so much eye strain.

as said, this will diminish. you should plan on some testing time, no
matter what. buzz out your board to find those hidden shorts and
such. By the way, I picked up a stereo microscope at a local auction.
It really helps for this sort of thing.

> 6) Rather slow - step-by-step process. I am sure would get faster
> with time and practice.

Yes, you will/would. I've gotten to the point where I can do a board
in about 2.5 hrs of effort.


Have fun with the CNC approach. there are many advocates but its got
its own set of issues as others are sure to point out.