Homebrew PCBs

> > andrewm wrote:
> ST Wrote :

> > It takes some time to make.
> Not really, if you start with HCl and H2O2 you
> can immediately etch boards and just have it
> grow.

Ok - yeah - I suppose.  I made my CuCl in a big
batch to the right concentration/density before
ever using it - and that took a few days.

If you go the HCl + H202 route you can etch
WHILE making it.

Question for you though.  Is it very aggressive
on resist and does it undercut much when doing
it like that ???

I have found if the acid is very high in my CuCl
I seem to get more undercut than when it is
lower.

Is there a disadvantage to making it as you use
it ?  Or should I recomend that route to everyone
that asks me ?

> Remember the other etchants are usually
> made up from powder or crystals as well, unless
> you get bottled FeCl.

Probably comes down to the philosiphy of "making
CuCl" again.  I made mine to be CuCl right from
the outset rather than HCl+H2O2.  And that was a
lot more work than "add XXX grams of power to XXX
mL of hot water"

> > It takes some time to look after before use.
> Does it? I usually drop the board right in and
> then add some H2O2 if i believe it is too dark
> to make the board. Every few months (if i feel
> like  it) i'll measure molarity and add HCl,
> usually while waiting for a board to etch.

Yeah - If you use it a lot you don't need to
check it every time.  Mine goes for weeks/months
without use - so I have to check molarity/density
almost every time before I use it. (usualy needs
water)

> > Vapours from it can wreak things.
> Indeed that is an issue. You need a lid on
> the tank. I have found it doesn't have to be
> totally airtight but it should be closed.

I solve the wreaking things problem by keeping
it outside in a big PE storage box - (thats
what leads to the last problem)

> > Your neighbours look at you funny and call
> >     the anti-terrorisim hotline when you are
> >     using it outside.
> 
> Don't show them ;-). The other etchants may
> cause funny looks too...

Ah - but I used to do my other etching inside.
Now there is nasty HCl fumes I have to do it
outside and wear clothes while etching.
(maybe I am just moaning at having to wear
clothes - I dont know)

But - still big thumbs up to CuCl.

ALL you people out there - if you etch
regularly - use it :D