Homebrew PCBs

I have been using "the" toner transfer method for about 2 years and 
produced some very good PCBs.
Until a week ago!
I had problems making the toner sticking to the copper.

After a lot of frustration I tracked the problem to the kind of 
liquid soap I used with Scotchbright pads to clean the copper.

It turned out that my wife changed the brand of liquid soap to 
one "that is kind to your skin". So it may be - but it leaves an 
invisible (oily?) film on the copper which is virtually undetectable.

Using my old liquid soap brand cured the problem.

I feel pretty silly now, but then again 20:20 hind sight always leads 
to highly accurate observations.

The moral of the story is of course - check the cleaning agent and 
don't let your wife decide the brand.

Frank

I still swear this:
After the scotch brite and cleaner,
the last thing to touch the board is either a wipe with acetone, or 
denatured alcohol (what I usually have on hand) and a quick little blow 
dryer to remove
any moisture that condenses from the evaporation.

-Lee

Lee Studley wrote:
> I still swear this:
> After the scotch brite and cleaner,
> the last thing to touch the board is either a wipe with acetone, or 
> denatured alcohol (what I usually have on hand) and a quick little blow 
> dryer to remove
> any moisture that condenses from the evaporation.
> 
> -Lee
> 

I found water still beads on the surface after that method. Only way 
I've found to get a continuous water film over the entire copper surface 
is to scotch brite it with heavy duty NaOH based degreaser.

At 04:47 PM 1/30/2009, you wrote:
>the last thing to touch the board is either a wipe with acetone

Don Lancaster, famed electronics writer online at the guru's lair has 
said that after chemical cleaning, the board should be quickly dipped 
into ferric chloride and then well rinsed before beginning any kind 
of PC resist coverage. he said that a truly clean copper board is the 
"pink" board that you see during etching, not the shiny brassy color 
of even a cleaned copper blank. although i've had very good results 
over the years with scores of boards by scrubbing the blanks with a 
brass-bristled brush in a sudsy ammonia bath and then a good rinse. i 
learned this trick from an old antiques dealer who cleaned all brass 
and copper antiquities in his shop in this manner.


William Alford

GI Motility Medical Research Page
http://alford.grimtrojan.com/ 

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

On Sun, 01 Feb 2009 00:48:37 -0600
William Alford <walford@...> wrote:

> he said that a truly clean copper board is the 
> "pink" board that you see during etching, not the shiny brassy color 
> of even a cleaned copper blank.

Now there's a good idea... and the dull surface may actually be better for
accepting toner transfer too.

Thanks,
John

I want to try this for ages but never get around to it, if anyone
tries with TT let us know if you see a difference.
I have few problems with toner adhesion, but do need to sand the
boards with an abrasive pad. Maybe that could be dispensed with.

What i noticed is if you dip a board in etchant you will immediately
see any dirt on the surface, such like grease or oil.

ST

On Sun, Feb 1, 2009 at 6:54 PM, John Coppens <john@...> wrote:

> Now there's a good idea... and the dull surface may actually be better for
> accepting toner transfer too.
>
> Thanks,
> John
>

--- In Homebrew_PCBs@yahoogroups.com, William Alford <walford@...> wrote:
...
> 
> Don Lancaster, famed electronics writer online at the guru's lair has 
> said that after chemical cleaning, the board should be quickly dipped 
> into ferric chloride and then well rinsed before beginning any kind 
> of PC resist coverage. 

...

> 
> William Alford
> 
> GI Motility Medical Research Page
> http://alford.grimtrojan.com/ 
> 
> [Non-text portions of this message have been removed]
>

Yesterday I was working on some small urgently needed boards using
toner transfer and my usual methods.  Everything went well enough
until i ran out of fresh board material and needed to reuse some that
had been used for an earlier, incorrect pattern.  

Suddenly, though I cleaned with 91% IPA, then Acetone, then Toluene,
used Scotchbrite and Bar Keeper's Friend copper cleanser, one at a
time and then in combinations, I could not get acceptable toner
adhesion.  

In desperation I put the cleaned board into the ferric chloride for
just long enough to see a patina.  It wasn't pretty - the slight
whorls and general unevenness in the copper's color made me uneasy
about trying this.  But after that things went much better, and I
finished the project.

Like traditional photography, the limitations one has on process
control makes producing small quantity PCBs a challenge, and sometimes
something of a mystery.

Dave Witten

I dip my pcbs in white Vinegar, which cleans well and also etches very 
little of the copper. I then wash the dirty spots and dip again if required. 
So far it has worked well for me.
Kim

I don't use any chemicals to clean my PCB panels.  I use Scotch-Brite 
pads and dish soap & hot water to clean my PCB panels before putting 
the toner pattern on them.

I like the Red Scotch-Brite pads better then the Green ones, as the 
Red pads are a bit more aggressive then the Green ones - and the Red 
pads seem to last longer.

The Scotch-Brite pads scuff up the Copper just enough to provide some 
roughness, allowing the toner to adhere better to the Copper, but 
also causing no distortion to the toner pattern when it's fused to 
the Copper.

I use dish soap because it is specifically designed to cut grease & 
oil, which is what you want to get good fusing of the toner to the 
CLEAN Copper.

I use as high a water temperature and I can tolerate, as this helps 
the PCB blank to dry as quickly as possible, helping reduce 
oxidization of the Copper.  A clean bath towel to Pat the blank PCB 
down with also ensures no oxidization and Copper discoloration occurs.

I try to fuse the toner pattern to the freshly cleaned PCB blank 
within a few minutes, and then get the patternized PCB blank into the 
enchant as quickly as possible, also reducing any chance of 
oxidization and Copper contamination.

Further, I don't touch any exposed Copper area with my fingers after 
I've cleaned the surface of the blank PCB panel, as the oil from ones 
fingers will prevent the toner from adhering to the Copper, as well - 
always hold the prepared PCB blank by it's edges.

These are some of the things that I've learned and use over the past 
10 years or so of using the Toner Transfer method of applying artwork 
patterns to Copper clad PCB material.

I hope it helps...


--- In Homebrew_PCBs@yahoogroups.com, "pork_u_pine2000" <wittend@...> 
wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, William Alford <walford@> 
wrote:
> ...
> > 
> > Don Lancaster, famed electronics writer online at the guru's lair 
has 
> > said that after chemical cleaning, the board should be quickly 
dipped 
> > into ferric chloride and then well rinsed before beginning any 
kind 
> > of PC resist coverage. 
> 
> ...
> 
> > 
> > William Alford
> > 
> > GI Motility Medical Research Page
> > http://alford.grimtrojan.com/ 
> > 
> > [Non-text portions of this message have been removed]
> >
> 
> Yesterday I was working on some small urgently needed boards using
> toner transfer and my usual methods.  Everything went well enough
> until i ran out of fresh board material and needed to reuse some 
that
> had been used for an earlier, incorrect pattern.  
> 
> Suddenly, though I cleaned with 91% IPA, then Acetone, then Toluene,
> used Scotchbrite and Bar Keeper's Friend copper cleanser, one at a
> time and then in combinations, I could not get acceptable toner
> adhesion.  
> 
> In desperation I put the cleaned board into the ferric chloride for
> just long enough to see a patina.  It wasn't pretty - the slight
> whorls and general unevenness in the copper's color made me uneasy
> about trying this.  But after that things went much better, and I
> finished the project.
> 
> Like traditional photography, the limitations one has on process
> control makes producing small quantity PCBs a challenge, and 
sometimes

> something of a mystery.
> 
> Dave Witten
>

... and if you add salt to the vinegar, you get dilute hydrochloric  
acid and it strips off any oxide like it was never there (try it with  
a filthy dark brown copper coin). I'm kinda through my "honeymoon"  
period on DIY PCBs, and probably wont be etching a few for a while,  
but I suspect the salty vinegar dip would be highly effective,  
provided you've got any oily stains off. I'll certainly be trying it  
when I do make a PCB again.

PG

On 02/02/2009, at 7:02 AM, Kim Vellore wrote:

> I dip my pcbs in white Vinegar, which cleans well and also etches very
> little of the copper. I then wash the dirty spots and dip again if  
> required.
> So far it has worked well for me.
> Kim
>
>
>

At 03:05 PM 2/1/2009, you wrote:
>get the patternized PCB blank into the enchant as quickly as 
>possible, also reducing any chance of
>oxidization and Copper contamination.

don't really think  you have to worry about this one as far as 
etching is concerned, as long as they are kept from getting filthy. i 
used to produce multi-copy pc boards by screen printing resist onto 
the boards. i've etched boards that were stored over a year after 
i've printed them, with various discoloration on the exposed copper 
and when etched in ferric chloride, worked just fine.

>Further, I don't touch any exposed Copper area with my fingers after
>I've cleaned the surface

this one is vitally important.


William Alford

GI Motility Medical Research Page
http://alford.grimtrojan.com/ 

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

> I have been using "the" toner transfer method for about 2 years and
> produced some very good PCBs.
> Until a week ago!
> I had problems making the toner sticking to the copper.
> 
> After a lot of frustration I tracked the problem to the kind of
> liquid soap I used with Scotchbright pads to clean the copper.
> 
> It turned out that my wife changed the brand of liquid soap to
> one "that is kind to your skin". So it may be - but it leaves an
> invisible (oily?) film on the copper which is virtually undetectable.
> 
> Using my old liquid soap brand cured the problem.


That's a common story, the jewellery people complain about it to.  They
polish metal (including copper) by tumbling, and add a bit dish washing
liquid.

The main one seems to be manufacturers adding anti-bacterial agents (which
are useless anyway) to the mix.

I've found Simple Green works well, I've used it to clean parts before
powdercoating (it's very fussy too), but I've yet to try it for PCBs.  It's
far more pleasant than acetone etc that I was using.

Tony

--- In Homebrew_PCBs@yahoogroups.com, "frankwinter1"
<frankwinter1@...> wrote:
>
> I have been using "the" toner transfer method for about 2 years and 
> produced some very good PCBs.
> Until a week ago!
> I had problems making the toner sticking to the copper.
> 
> After a lot of frustration I tracked the problem to the kind of 
> liquid soap I used with Scotchbright pads to clean the copper.
> 
> It turned out that my wife changed the brand of liquid soap to 
> one "that is kind to your skin". So it may be - but it leaves an 
> invisible (oily?) film on the copper which is virtually undetectable.
> 
> Using my old liquid soap brand cured the problem.
> 
> I feel pretty silly now, but then again 20:20 hind sight always leads 
> to highly accurate observations.
> 
> The moral of the story is of course - check the cleaning agent and 
> don't let your wife decide the brand.
> 
> Frank
>



A mild etching of the copper before lamination will always help
adhesion of the etch resist. This process is known as micro etching. I
use a Dupont hot roll laminator to apply dry film photoresist for my
boards but always microetch the blank panels first. One method that
works good is a vinegar and peroxide mixture. This makes a very weak
etchant that leaves a matte surface on the copper. Here is my process:

Wet sand copper with 220 grit sandpaper using a bit of dish detergent

Water rinse

Soak in the microetch mixture for five minutes

Rinse and dry

Laminate dry film photoresist with hot roll laminator

Wait thirty minutes for photoresist to bond 

Expose panels using film negative and UV light

Wait twenty minutes for photoresist to polymerize 

Develop in 1% sodium carbonate (soda ash) solution

Rinse

Etch copper panels

Rinse and dry

This is the process I use and I make a lot of boards with almost zero
rejects. Sanding and microetching the copper panels first is the most
important step. Proper adhesion of the etching resist is critical as
this prevents the etchant from lifting the edge of the resist. Micro
etching should be used no matter what type of etch resist system you
plan to use. 

Tom

--- In Homebrew_PCBs@yahoogroups.com, Lee Studley <indigo_red@...> wrote:
>
> I still swear this:
> After the scotch brite and cleaner,
> the last thing to touch the board is either a wipe with acetone, or 
> denatured alcohol (what I usually have on hand) and a quick little blow 
> dryer to remove
> any moisture that condenses from the evaporation.
> 
> -Lee
>


I, like Carl and Lee, have excellent results with just a Scotch Brite
pad and dish soap.

I scrub the board in hot water with a strong application of Dawn dish
soap( just plain 'Blue' Dawn as it cleans and cuts grease and doesn't
have any extras). I apply a few drops to the board (a generous
concentration of Dawn) and scrub with a green Scotch pad in both
directions until all is smooth and shiny. Then I rinse well and blot
with a plain cheap white paper towel. That's good enough to do the
trick every time. Sometimes the board gets handled afterwards (such as
forgot to drill the alignment holes) in which case I'll wipe it with
99% alcohol before applying the TT. I soak part of a plain white paper
towel with the alcohol and wipe the board good on both sides. I let it
air dry as the alcohol is 99% and it dries clean. Many solvents don't
dry clean as they are petroleum based and leave an oily residue or
other films behind. Those who remember the old days know there are
only two solvents acceptable for cleaning tape heads ... Freon TF
(good luck finding that one anymore) and 99% alcohol, because these
both leave no residue behind. I always use alcohol for a final wipe if
I need one.

I use Toner Transfer and never have a bonding problem with this
method. Always 100% on trace adhesion with old or new boards. Micro
etching the board is simply not necessary for this process.

One other note, I've seen references to sanding with some pretty
coarse grits. I'd be careful of using the sand paper as 1oz copper is
only 1.34 mils thick (0.00134") and 1/2 oz copper is half that.
Sanding would significantly reduce the thickness of the copper
possibly leaving it very thin in some areas. I'd personally hesitate
to use anything coarser than 600 to 800 grit (and wet) myself.
phil - KA0HBG

--- In Homebrew_PCBs@yahoogroups.com, "Carl W. Livingston"
<microcarl@...> wrote:
>
> I don't use any chemicals to clean my PCB panels.  I use Scotch-Brite 
> pads and dish soap & hot water to clean my PCB panels before putting 
> the toner pattern on them.
> 
...

> 
> I hope it helps...
> 

Point taken, but since when isn't 'dish soap' a mystery mix of
chemicals?  Usually the stuff from the grocery is some undisclosed
mixture of synthetic detergents, semi-synthetic detergents, coloring,
perfume, and thickening agents.  No soap (soaponified fats) at all. 
Sometimes the stuff from the 'health food' stores is even scarier.

-- dave

--- In Homebrew_PCBs@yahoogroups.com, "pork_u_pine2000" <wittend@...> 
wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "Carl W. Livingston"
> <microcarl@> wrote:
> >
> > I don't use any chemicals to clean my PCB panels.  I use Scotch-
Brite 
> > pads and dish soap & hot water to clean my PCB panels before 
putting 
> > the toner pattern on them.
> > 
> ...
> 
> > 
> > I hope it helps...
> > 
> 
> Point taken, but since when isn't 'dish soap' a mystery mix of
> chemicals?  Usually the stuff from the grocery is some undisclosed
> mixture of synthetic detergents, semi-synthetic detergents, 
coloring,
> perfume, and thickening agents.  No soap (soaponified fats) at all. 
> Sometimes the stuff from the 'health food' stores is even scarier.
> 
> -- dave
>
OK, poor choice of wording...

I don use anything other then dish soap and Scotch-Brite pads to 
clean the Copper on my PCB blanks.

Is that a bit more generic???

I have been using the same simple method for years and it works very well. I 
scrub the board with no-name steel wool soap pads from the supermarket. Then 
I give it a good rub down with acetone on a paper towel. Then iron on toner 
transfer from Epson No S041140 photo paper or 100gsm glossy paper from 
Officeworks printed on a HP laserjet. I use a 2400W iron on the hottest 
setting.

Works perfectly. The Epson paper floats off beautifully in a water bath. The 
Officeworks paper needs a bit of frictional encouragement.

Morris