Homebrew_PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:

> On Wed, 07 Sep 2005 15:57:41 +0200, lcdpublishing
> <lcdpublishing@y...> wrote:
>
> > 1) I am working with the powder, according to the directions, I

add

> > the powder to the water - 1 pound / 1/2 gallon. They caution to

add

> > it slowly as it could react and bubble up or get very warm. Any
> > other worries at this point?
>
> seems about right. watch those stains!!
> if you mix it fresh before your first etch you can use the heat in

the

> etchant i guess. Wasn't too dramatic.
>
> > 2) I will be using a small fish tank pump and bubbler rocks to
> > create a wide spread of bubbles. This will be my first time

etching

> > with bubbles - I expect that this will speed up the etching

process?

>
> yes, similar to mechanic agitation or brushing.
>
> > 3) I also have a fish tank heater. I am not sure if I will use

this

> > or not the first time around. However, I have read the

comments " I

> > am using a hacked fish tank heater to warm the solution ". This
> > creates two questions for me.
> > 3a) How hot do you need to make the solution?
>
> i remember something a small bit below 50C for ideal speed.
>
> > 3b) Do you really need to modify the heater to obtain the heat
> > desired or can you use it without modification?
>
> The fish would die, if there was no safety limit. many heaters can

be

> hacked by removing some sort of mechanical stop.
> Please keep in mind ferric chloride is about as conductive as

liquids get,

> so take care with the electrics.
>
>
> > 4) I suspect if I use any form of metal clip to hang the circuit
> > board in the tank, it will probably corrode away and "waste" the
> > ferric chloride. So, I am thinking of hanging the circuit boards
> > with wire (insulated), is this a good idea?
>
> all but titanium will be etched, i think. You can use a plastic

clamp, a

> strip of sticky tape, a hole and some cord, .....
>
> > 5) based on the above descriptions ( and any modifications you

folks

> > add), how long does etching take using this process? I don't

want

> > to over etch, and trying to see though that brown solution isn't
> > very good. I will of course have to lift out the circuit board

to

> > check it's progress, but if someone can provide an approximate

time

> > that would be helpful in that I could detect if something is

wrong.

>
> you must lift out the circuit board to check from time to time, it

is in

> the minutes range under good conditions up to hours under bad ones.
>
> good luck, and i hope you bought the stain remover too, for any

accidents

> ;-)
>
> ST

No, no stain remover, but I have plenty of old clothes that would
probably look better with a few stains :-)

Thanks Stefan, I hope to get some time today to do this but the day
is fading fast on me.

Chris