diy pcb making problem (acid + oxygenated water)

[Rafael Ignacio Zurita]

Hi, I have been trying to make a diy pcb.
Before I have had success, but I do not know really now (in my new diy
lab) what is the problem.

I am using toner transfer and acid to make the board. My problem is
the acid part.
What I am seeing is that the toner is removed when I am trying to
remove the copper with acid. Then, the board left ruin :(

I show two pictures :

first, the toner transfer looks okey for me :
Loading Image...

Then, when I put the board for a few minutes in the acid 50% +
oxygenated water 50% I get this board with destroyed tracks :(
Loading Image...

If somebody has some ideas about this kind of making the board and
this problem I would appreciate some help.

Thanks in advance,
Rafa
P.S. The board is for using a mk20dx256 from freescale

[Werner Almesberger]

Post by Rafael Ignacio Zurita
What I am seeing is that the toner is removed when I am trying to
remove the copper with acid. Then, the board left ruin :(

Interesting effect :-) How long did you etch until you got
this ?

Post by Rafael Ignacio Zurita
http://fz.hobby-site.org/hp660lx/board-problem.jpg

The solution looks very green. Maybe add a bit of 30% peroxide
until the color gets more blueish. You also seem to have a lot of
etching solution. You only need enough to submerge the board.

If you use a hermetically sealable container, you can reuse the
solution. If it gets stale, you can refresh it by adding a bit of
HCl and peroxide.

- Werner

[Rafael Ignacio Zurita]

On Thu, Aug 27, 2015 at 12:28 PM, Werner Almesberger

Post by Werner Almesberger

Post by Rafael Ignacio Zurita
What I am seeing is that the toner is removed when I am trying to
remove the copper with acid. Then, the board left ruin :(

Interesting effect :-) How long did you etch until you got
this ?

I got that "interesting effect" in few boards I tried :(
But I do not loose the hopes ;)

it lasted around 7min - 10min etching I think

Post by Werner Almesberger

Post by Rafael Ignacio Zurita
http://fz.hobby-site.org/hp660lx/board-problem.jpg

The solution looks very green. Maybe add a bit of 30% peroxide
until the color gets more blueish. You also seem to have a lot of
etching solution. You only need enough to submerge the board.
If you use a hermetically sealable container, you can reuse the
solution. If it gets stale, you can refresh it by adding a bit of
HCl and peroxide.

Thanks a lot Werner. I will try with a bit more of peroxide like you suggested.
News soon :)

Rafa

[Werner Almesberger]

Post by Rafael Ignacio Zurita
I got that "interesting effect" in few boards I tried :(

I've never seen anything like this. Maybe the toner chemistry
is unusual.

Did you clean the PCB with alcohol before applying the toner ?
When cleaning, you'll also remove any (usually black) residues
from the steel wool you used for scrubbing.

Post by Rafael Ignacio Zurita
it lasted around 7min - 10min etching I think

This sounds like a reasonable duration. By increasing the
peroxide concentration you'll make it faster, which may help.

- Werner

[Rafael Ignacio Zurita]

On Thu, Aug 27, 2015 at 12:48 PM, Werner Almesberger

Post by Werner Almesberger

Post by Rafael Ignacio Zurita
I got that "interesting effect" in few boards I tried :(

I've never seen anything like this. Maybe the toner chemistry
is unusual.
Did you clean the PCB with alcohol before applying the toner ?
When cleaning, you'll also remove any (usually black) residues
from the steel wool you used for scrubbing.

Werner, your tips did this now :

Loading Image...

Thanks a lot! I did both tips, a good cleaning of PCB and less
muriatic acid than oxygenated water.

Now I can rest

Rafa

[Werner Almesberger]

Post by Rafael Ignacio Zurita
http://fz.hobby-site.org/hp660lx/20150828_085752.jpg

A feast for sore eyes ! :-) Congratulations !

Post by Rafael Ignacio Zurita
Now I can rest

s/rest/solder/ ;-)

Not sure how long you can leave the board like this before
you get nasty copper oxidation. In any case, once you've
removed the toner, you should quickly tin all the traces.

- Werner

[Rafael Ignacio Zurita]

On Fri, Aug 28, 2015 at 10:09 AM, Werner Almesberger

Post by Werner Almesberger

Post by Rafael Ignacio Zurita
http://fz.hobby-site.org/hp660lx/20150828_085752.jpg

A feast for sore eyes ! :-) Congratulations !

Post by Rafael Ignacio Zurita
Now I can rest

s/rest/solder/ ;-)

ok ok, ... soldering in progress
Loading Image...

Post by Werner Almesberger
Not sure how long you can leave the board like this before
you get nasty copper oxidation. In any case, once you've
removed the toner, you should quickly tin all the traces.

I will try to do this then as well.

Thanks a lot,
Rafa