Homebrew PCBs

Hi all,

I obtained some surplus PCB material recently which was pre-coated 
with some sort of photo resist. The coating is red/orange coloured 
and in poor condition. My question is, How can I get this stuff off? 
I have tried acetone, alcohol, soap & water, citrus cleaner and 
Shellite (a hydrocarbon based solvent) all to no or little avail.

Anybody recognise this stuff and know how to remove it?

Thanks,

Morris

Try lacquer thinners then steel wool & ajax. Colin
On 28/12/2008, at 12:44 PM, morriso2002 wrote:

> Hi all,
>
> I obtained some surplus PCB material recently which was pre-coated
> with some sort of photo resist. The coating is red/orange coloured
> and in poor condition. My question is, How can I get this stuff off?
> I have tried acetone, alcohol, soap & water, citrus cleaner and
> Shellite (a hydrocarbon based solvent) all to no or little avail.
>
> Anybody recognise this stuff and know how to remove it?
>
> Thanks,
>
> Morris
>
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and  
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

Alma & Colin Lane
Adelaide, South Australia
Skype     colinalma
clan1623@...






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

In a message dated 12/27/2008 8:14:34 P.M. Central Standard Time,  
vilgotch@... writes:

Anybody recognise this stuff and know how to remove  it?




Morris:  Use lacquer thinner.  I THINK this is known as Amyl  Acetate.  You 
MAY have to submerge the PC board under a few mm. of that  solvent for half 
hour, to "break it loose".  You might try wiping it off  with several mm. of the 
said thinner atop it (in a shallow pan) with Scotchbrite  abrasive (this is a 
textile coated with very fine abrasive grit, effectively  similar to 0000 
steel wool).
**************One site keeps you connected to all your email: AOL Mail, 
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[Non-text portions of this message have been removed]

----- Original Message ----- 

From: "morriso2002" <vilgotch@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, December 28, 2008 2:14 AM
Subject: [Homebrew_PCBs] PCB resist cleaning question


> Hi all,
>
> I obtained some surplus PCB material recently which was pre-coated
> with some sort of photo resist. The coating is red/orange coloured
> and in poor condition. My question is, How can I get this stuff off?
> I have tried acetone, alcohol, soap & water, citrus cleaner and
> Shellite (a hydrocarbon based solvent) all to no or little avail.
>
> Anybody recognise this stuff and know how to remove it?

Try leaving them in NaOH solution. It's a developer, but a concentrated 
solution is used for stripping the resist. It depends on the resist, though. 
Rubbing with IPA might work, as well.

Leon

If you already tried acetone, i believe you are out of luck with solvents.

Try strong developer (NaOH) for some time, see if that gets it off.

The problem with mechanical removal (sanding) may well be that you
thin out the copper too much in some areas before all of the resist is
removed.

ST

On Sun, Dec 28, 2008 at 3:14 AM, morriso2002 <vilgotch@...> wrote:
> Hi all,
>
> I obtained some surplus PCB material recently which was pre-coated
> with some sort of photo resist. The coating is red/orange coloured
> and in poor condition. My question is, How can I get this stuff off?
> I have tried acetone, alcohol, soap & water, citrus cleaner and
> Shellite (a hydrocarbon based solvent) all to no or little avail.
>
> Anybody recognise this stuff and know how to remove it?
>
> Thanks,
>
> Morris
>

morriso2002 wrote:
> Hi all,
> 
> I obtained some surplus PCB material recently which was pre-coated 
> with some sort of photo resist. The coating is red/orange coloured 
> and in poor condition. My question is, How can I get this stuff off? 
> I have tried acetone, alcohol, soap & water, citrus cleaner and 
> Shellite (a hydrocarbon based solvent) all to no or little avail.
> 
> Anybody recognise this stuff and know how to remove it?
> 
> Thanks,
> 
> Morris

Its most likely negative dry film resist. If so then room temp 3~5% NaOH 
will strip it off in a 5~10 minutes (no scrubbing as it will swell and 
just lift off the copper). You'll damage the copper removing it any 
other way. Most common solvents and household cleaners won't touch these 
photoresists once polymerised.

It's almost as if they were designed to resist ;-)

ST

On Sun, Dec 28, 2008 at 11:22 AM, Adam Seychell <a_seychell@...> wrote:
> Most common solvents and household cleaners won't touch these
> photoresists once polymerised.
>

Morris,

its probaly negative resist that has been exposed or aged,
Xylene or Xyloh(Xylene with Alcohol) should remove it, 
you may need to soak for a while if its old.

BoonS

--- In Homebrew_PCBs@yahoogroups.com, Colin & Alma Lane 
<clan1623@...> wrote:
>
> Try lacquer thinners then steel wool & ajax. Colin
> On 28/12/2008, at 12:44 PM, morriso2002 wrote:
> 
> > Hi all,
> >
> > I obtained some surplus PCB material recently which was pre-
coated
> > with some sort of photo resist. The coating is red/orange 
coloured
> > and in poor condition. My question is, How can I get this stuff 
off?
> > I have tried acetone, alcohol, soap & water, citrus cleaner and
> > Shellite (a hydrocarbon based solvent) all to no or little avail.
> >
> > Anybody recognise this stuff and know how to remove it?
> >
> > Thanks,
> >
> > Morris
> >
> >
> >
> >
> > ------------------------------------
> >
> > Be sure to visit the group home and check for new Links, Files, 
and  

> > Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
> 
> Alma & Colin Lane
> Adelaide, South Australia
> Skype     colinalma
> clan1623@...
> 
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

Bingo! NaOH worked like a charm but took a little longer than 10 
minutes.

Thanks to all for your suggestions.

Morris


--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@...> 
wrote:
>
> How can I get this stuff off? 
> > I have tried acetone, alcohol, soap & water, citrus cleaner and 
> > Shellite (a hydrocarbon based solvent) all to no or little avail.
> > 
> 
> Its most likely negative dry film resist. If so then room temp 3~5% 
NaOH 
> will strip it off in a 5~10 minutes (no scrubbing as it will swell 
and 
> just lift off the copper). You'll damage the copper removing it any 
> other way. Most common solvents and household cleaners won't touch 
these 
> photoresists once polymerised.
>