Homebrew PCBs

Okay,

I am about to take my first "real" etching tank for a test drive 
today.  There are a number of "Firsts" in this for me.

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?

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?

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?

3b) Do you really need to modify the heater to obtain the heat 
desired or can you use it without modification?

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?

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.

TIA!

Chris

On Wed, 07 Sep 2005 15:57:41 +0200, lcdpublishing  
<lcdpublishing@...> 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

--- 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

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:
> Okay,
> 
> I am about to take my first "real" etching tank for a test drive 
> today.  There are a number of "Firsts" in this for me.
> 
> 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?

nasty stuff.  wear old clothes.  mix in a large vessel as splashing
and sizzling can get pretty intense if you over do it.  at this point
I suspect AP will sound pretty good :)  There is a non-anhydrous form
of FeCl that people have mentioned that doesn't sizzle/splash/heat but
I've never seen it.

> 
> 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, speed up some but also make it more uniform.  You'll get better
speed up by heating the etchant.

> 
> 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?
> 
> 3b) Do you really need to modify the heater to obtain the heat 
> desired or can you use it without modification?

I use a Top Fin heater.  I don't know if it's similar to yours but I
suspect they all come from the same chinese factory.  There is a
mechanical stop that prevents much above 100F.  You can leave it this
way and it will etch ok - about 12-15 minutes, typical.   But, I like
my etchant at about 130F.  I've heard of people going up to 160F but I
don't know how my plexiglass tank will take it.  

You can remove the mechanical stop but there is a themo safety switch
(I don't know the correct name) that trips off at 110F.  It takes
about 10 minutes to reset so I shorted it out (just twisted it) and
use a dimmer to control the temp.  I'll someday build a real temp
controller for it.

> 
> 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?

enamel coated wire is great, I use it all the time.

> 
> 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.


some thoughts (many of which I'm sure you have figured out):
- keep your tank in a larger tub - there will be
  splashes and FeCl makes a gawdawful mess.
- wear a rubberized apron (and your worst 
  old clothes)
- use rubberized gloves
- eye protection (the thought of a splash of FeCl
  in the eye gives me the willys)
- make it easy to lift the board out with one hand
  for inspection

Have fun and let us know your results

Phil

On Wed, 07 Sep 2005 19:58:18 +0200, Phil <phil1960us@...> wrote:

>
> nasty stuff.  wear old clothes.  mix in a large vessel as splashing
> and sizzling can get pretty intense if you over do it.  at this point
> I suspect AP will sound pretty good   There is a non-anhydrous form
> of FeCl that people have mentioned that doesn't sizzle/splash/heat but
> I've never seen it.


I mixed it in a PET bottle (filled with cold water and added FeCl with a  
funnel) and the heating wasn't bad. Splashing was not a problem in the  
bottle. You can do it near a sink then you could put the bottle in a cold  
water bath should it get too hot. The thing to remember is start out with  
what the label suggests on water, no less. If you think you'll add some  
water later you'll potentially have too much ferric chloride and not  
enough water, and it could overheat.


As for eye protection, i found i much prefer a face shield over goggles.  
Not so much of a difference with chemicals, as i never had an accident,  
but when sawing etc. somehow the chips always find their way round the  
goggles into my eyes. (Even have burnmarks on the EYE-SIDE of optical  
glasses over which i wore ALLROUND CLOSED safety goggles when using the  
angle grinder)
Dunno but those goggles do not seem to fit my face ;-)... hmmm maybe i  
ought to try a diving mask!

Anyway, the face shield is much better protection and visibility, and it  
was expensive so i make damn sure i avoid scratching it... wish they were  
more popular here so i could get them replacement plastic sheets in the  
shops.

ST

lcdpublishing wrote:

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

I find diluted (1:0) hydrochloric acid removes ferric chloride stains in 
minutes. Just apply a drop directly to the stain, then rinse.

Marketers have a habit of re-labeling and selling rudimentary products.

In a message dated 9/7/2005 3:47:15 P.M. Central Daylight Time,  
a_seychell@... writes:

I find  diluted (1:0) hydrochloric acid removes ferric chloride stains in 
minutes.  Just apply a drop directly to the stain, then  rinse.



Even quite diluted HCL will at least WEAKEN the fabric, no  matter HOW 
quickly you rinse!  I would not do this on "good  clothing"!


[Non-text portions of this message have been removed]

lol, if you are trying to remove an FeCl stain, it is no longer "good
clothing".

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
>  
> In a message dated 9/7/2005 3:47:15 P.M. Central Daylight Time,  
> a_seychell@y... writes:
> 
> I find  diluted (1:0) hydrochloric acid removes ferric chloride
stains in 

> minutes.  Just apply a drop directly to the stain, then  rinse.
> 
> 
> 
> Even quite diluted HCL will at least WEAKEN the fabric, no  matter HOW 
> quickly you rinse!  I would not do this on "good  clothing"!
> 
> 
> [Non-text portions of this message have been removed]

On Thu, 08 Sep 2005 08:46:04 +0200, Phil <phil1960us@...> wrote:

> lol, if you are trying to remove an FeCl stain, it is no longer "good
> clothing".
> --- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
>>
>> In a message dated 9/7/2005 3:47:15 P.M. Central Daylight Time,
>> a_seychell@y... writes:
>>
>> I find  diluted (1:0) hydrochloric acid removes ferric chloride
> stains in
>> minutes.  Just apply a drop directly to the stain, then  rinse.


Well, surely better than what i did!
I tried to get out a FeCl stain of a pair of jeans using some chlorine  
(tablet) meant for pool water treatment.
Oh well, i still had the FeCl stain, but now i also had a much larger  
bleached white area around it to highlight it ;-)

ST