Material for scrubbing Cu-clad boards

[pimpom]

This is for those of you who are making their own PCBs for hobby,
prototyping and low-volume production.

I've seen things like fine sandpaper and steelwool recommended on
hobbyist websites for cleaning copper-clad boards prior to
transferring the pattern and etching. 40 years ago, I used wood
ash. It worked quite well but wasn't always readily available.
Then I tried tooth powder as it's more abrasive than toothpaste.
It sort of worked, but required too much scrubbing. Then I got
the idea of using household scrubbing powder. It works fast,
having just the right amount of abrasive property with no danger
of inflicting deep scratches. Vim and Biz are two popular Indian
brands.

I feel no need to look for a better material, but I'm curious
about what others are using.

 

[Gerard Bok]

This is for those of you who are making their own PCBs for hobby,
prototyping and low-volume production.

I've seen things like fine sandpaper and steelwool recommended on
hobbyist websites for cleaning copper-clad boards prior to
transferring the pattern and etching.

I feel no need to look for a better material, but I'm curious
about what others are using.

It has been quite a while, but in the old days I used Seno
Polyblock. That is (or was) a kind of big (matchbox sized) crayon
eraser, specially made to clean Cu plating.
http://www.hamers.de/en/electronics/print6.php
shows a picture.

 

[Archimedes' Lever]

It has been quite a while, but in the old days I used Seno
Polyblock. That is (or was) a kind of big (matchbox sized) crayon
eraser, specially made to clean Cu plating.
http://www.hamers.de/en/electronics/print6.php
shows a picture.

The acid is going to eat it off of ALL the unmasked areas and a little
tarnish wont stop it. I think abrasive scrubbing was overkill this whole
time.

 

[Hammy]

This is for those of you who are making their own PCBs for hobby,
prototyping and low-volume production.

I've seen things like fine sandpaper and steelwool recommended on
hobbyist websites for cleaning copper-clad boards prior to
transferring the pattern and etching. 40 years ago, I used wood
ash. It worked quite well but wasn't always readily available.
Then I tried tooth powder as it's more abrasive than toothpaste.
It sort of worked, but required too much scrubbing. Then I got
the idea of using household scrubbing powder. It works fast,
having just the right amount of abrasive property with no danger
of inflicting deep scratches. Vim and Biz are two popular Indian
brands.

I feel no need to look for a better material, but I'm curious
about what others are using.

I use 400grit or finer sandpaper lightly and I don't get deep grooves.
I suppose for RF you would want a very light abrasive so as to keep
the cooper uniform. This assumes the board itself already has uniform
copper distribution. I doubt that most general purpose boards have
precision distribution .

 

[Gerard Bok]

The acid is going to eat it off of ALL the unmasked areas and a little
tarnish wont stop it. I think abrasive scrubbing was overkill this whole
time.

Acid ?
I use Polyblock to remove the photolayer.
That is after the etching process

 

[GregS]

Acid ?
Tarn-X



I use Polyblock to remove the photolayer.
That is after the etching process

 

[GregS]

Tarn-X

That should also get rid of oils with a little aggitation.

 

[pimpom]

The acid is going to eat it off of ALL the unmasked areas and
a
little tarnish wont stop it. I think abrasive scrubbing was
overkill
this whole time.

But FeCl3 has a hard time eating through grease and finger
smudges. I always have a stack of 12"x12" copper-clads in stock
and some of them go through a lot of handling and shuffling
before it's their turn to be used. And since it's best to remove
any tarnish anyway before soldering, scrubbing followed by a
thorough rinsing in running water ensures a smooth process.

 

[pimpom]

Acid ?
I use Polyblock to remove the photolayer.
That is after the etching process

I was really talking about pre-etch cleaning.

 

[pimpom]

I use 400grit or finer sandpaper lightly and I don't get deep
grooves.
I suppose for RF you would want a very light abrasive so as to
keep
the cooper uniform. This assumes the board itself already has
uniform
copper distribution. I doubt that most general purpose boards
have
precision distribution .

I suppose not. I'm not really concerned about that, but it's nice
to know that individual particles of the scouring powder are not
hard enough to score deeply into the copper. What I didn't
mention earlier was that I keep board and powder wet while
scrubbing. A level teaspoonful of powder is more than enough to
get a palm-sized board sparkling clean without any visible nicks
and scratches, and it takes under a minute of mild scrubbing
unless the board is heavily tarnished.

 

[pimpom]

I use a green nylon scrubbing pad (3M or generic equivalent)
with
either some Comet household scrubbing powder (for fast cutting)
or a
squirt of Gojo hand cleaner (an orange-scented gel which
contains some
pumice).

I tried using the green pad too, but I really prefer scrubbing
with my fingers. Of course, I wouldn't recommend it for mass
production!

On the last board I did, I scrubbed down the board in this way,
rinsed
well, and then dipped it into the PC-board etchant solution for
a few
seconds and then rinsed again. The brief dip in the etchant
left the
copper surface with a very uniform matte appearance - I think
it
evened out the larger scratches left by the pumice/cleanser.

The pattern ironed on quite well and etched nicely.

I sometimes do the pre-etch (brief dipping) too, but somehow I
don't have the patience to make it a regular practice. No logic
here as I'm normally a very patient type.

 

[Artemus]

There used to be a liquid cleaner for "Revere Ware", the copper
-bottom cooking pots. Use with a plastic or nylon scrubbing pad.

...Jim Thompson
--

Kleen King worked like a champ for me.
Art

 

[Archimedes' Lever]

Scotchbrite, with soapy water. When scotchbrite was first invented, it
was a very expensive industrial product and one of the first markets
was PCB fabbers. Years later it became a household product.

Use the green kind, the more agressive stuff, not the gentle version.

John

NEVR-DULL tarnish removal wadding will aid in getting the stuff scrubbed
off too. Also a very good pre-prep for the HASL to follow.

 

[D from BC]

Scotchbrite, with soapy water. When scotchbrite was first invented, it
was a very expensive industrial product and one of the first markets
was PCB fabbers. Years later it became a household product.

Use the green kind, the more agressive stuff, not the gentle version.

John

Yup..That's what I use. Or whatever generic synthetic scouring pad I can
get.

In the past I've tried Rag with abrasive( Vim, toothpaste, baking
soda),400 grit wet sanding paper, copper wool and steel wool.

 

[Joe]

Where's that? In supermarkets here, we have several brands of kitchen
sponges that have generic Scotchbrite on one side. They work great to
clean up pc boards.

He probably is in or near Tripura, Mizoram, or Manipur,
some Indian States that are 300-500 Km east of Kolkata.

 

[Tim Watts]

The acid is going to eat it off of ALL the unmasked areas and a little
tarnish wont stop it. I think abrasive scrubbing was overkill this whole
time.

I've used those blocks after etching to get nice bright copper prior to a
quick spray of hobby grade conformal coating. 000 grade (super fine) steel
wool would be OK too, as long as you wash all the strands off afterwards.

 

[Robert Roland]

The acid is going to eat it off of ALL the unmasked areas and a little
tarnish wont stop it.

It depends on the acid. Ferric chloride, which is popular among
hobbyists, is stopped even by a fingerprint.

If you use toner transfer, it is essential that the copper is clean,
otherwise the toner will not stick reliably.

 

[pimpom]

He probably is in or near Tripura, Mizoram, or Manipur,
some Indian States that are 300-500 Km east of Kolkata.

That's right. I'm in Aizawl, Mizoram.

 

[Archimedes' Lever]

It depends on the acid. Ferric chloride, which is popular among
hobbyists, is stopped even by a fingerprint.

If you use toner transfer, it is essential that the copper is clean,
otherwise the toner will not stick reliably.

A laser printer prints on both conductive and non-conductive surfaces,
but you want clean copper because you want the resist directly on the
copper, not on a fingerprint.

 

[[email protected]]

That's right. I'm in Aizawl, Mizoram.

Neat, India to the East of Bangladesh.