Homebrew PCBs

Hi,

Can anyone suggest any chemicals which can dissolve paper fragments
from a toner-transferred board without damaging the toner deposits or
eating into the exposed copper?

Background:

After some experimentation with thermal toner transfer technique, I've
been getting the best and most reproducible PCB artwork results by:

1) Laser-printing the artwork onto glossy inkjet paper (this gets me
good quality image transfer - 'time magazine' glossy paper tends to
distort the image)
2) Putting paper onto board, for 10 passes through laminator
3) Soaking paper+board in warm water
4) Peeling off the bulk of the paper (some remains stuck to board)
5) Removing remaining paper fragments by gently rubbing board with
fingers under water
6) Using a head-magnifier and a fine knife, carefully picking off tiny
remaining fragments of paper, taking care not to damage toner deposits
7) Etching in FeCl
8) Removing toner with acetone

Biggest problem I'm having is with steps 5-6. This is a time-consuming
process. If there was a way to get the paper off fairly quickly,
without damaging toner or copper, that would be great.

Thanks in advance for any help

Cheers
David

On Dec 31, 2006, at 1:12 AM, daviddmcnab wrote:

> Can anyone suggest any chemicals which can dissolve paper fragments
> from a toner-transferred board without damaging the toner deposits or
> eating into the exposed copper?


Have you tried DMSO?   Of course, I haven't, so I wouldn't know if it  
would loosen the toner.

I thought of it because it's a solvent that's a waste product in  
paper manufacture.


Other than DMSO I'd think you might try an enzymatic cleaner to break  
up the paper fibers.


William

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

On Sun, 31 Dec 2006 07:12:45 +0100, daviddmcnab <david@...>  
wrote:

> 2) Putting paper onto board, for 10 passes through laminator
> 3) Soaking paper+board in warm water
> 4) Peeling off the bulk of the paper (some remains stuck to board)
> 5) Removing remaining paper fragments by gently rubbing board with
> fingers under water
> 6) Using a head-magnifier and a fine knife, carefully picking off tiny
> remaining fragments of paper, taking care not to damage toner deposits
> 7) Etching in FeCl
> 8) Removing toner with acetone
> Biggest problem I'm having is with steps 5-6. This is a time-consuming
> process. If there was a way to get the paper off fairly quickly,
> without damaging toner or copper, that would be great.
> Thanks in advance for any help
> Cheers
> David


If your toner is stuck well you can engage in step 5 quite vigorously  
which will eliminate step 6. In order to reduce wear to your fingers you  
can use some aid, like a piece of plastic foam, or even a rag. After  
peeling/rolling the bulk of the paper off i will rub the board with a foam  
piece, dipping it into water from time to time. When i feel confident that  
the paper should be gone i dip it again to rinse, and then dry it (wipe  
with a towel and wave it around or put on still hot fuser). The drying  
makes any remaining paper very obvious because it turns white. Such spots  
are rubbed again, either with a finger or the sponge, adding a little  
water, until all paper is cleared.

This all should take no more than a minute or so. If your toner is not  
stuck well enough to rub with significant force, then that's your problem.

ST

Try soaking in a little automatic dishwasher detergent. It is very caustic
and loosens the paper nicely.



On 12/31/06, daviddmcnab <david@...> wrote:
>
>   Hi,
>
> Can anyone suggest any chemicals which can dissolve paper fragments
> from a toner-transferred board without damaging the toner deposits or
> eating into the exposed copper?
>
> Background:
>
> After some experimentation with thermal toner transfer technique, I've
> been getting the best and most reproducible PCB artwork results by:
>
> 1) Laser-printing the artwork onto glossy inkjet paper (this gets me
> good quality image transfer - 'time magazine' glossy paper tends to
> distort the image)
> 2) Putting paper onto board, for 10 passes through laminator
> 3) Soaking paper+board in warm water
> 4) Peeling off the bulk of the paper (some remains stuck to board)
> 5) Removing remaining paper fragments by gently rubbing board with
> fingers under water
> 6) Using a head-magnifier and a fine knife, carefully picking off tiny
> remaining fragments of paper, taking care not to damage toner deposits
> 7) Etching in FeCl
> 8) Removing toner with acetone
>
> Biggest problem I'm having is with steps 5-6. This is a time-consuming
> process. If there was a way to get the paper off fairly quickly,
> without damaging toner or copper, that would be great.
>
> Thanks in advance for any help
>
> Cheers
> David
>
> 
>


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

--- In Homebrew_PCBs@yahoogroups.com, "daviddmcnab" <david@...> wrote:
>
> Hi,
> 
> Can anyone suggest any chemicals which can dissolve paper fragments
> from a toner-transferred board without damaging the toner deposits 
or
> eating into the exposed copper?
> (snip)


David, 

While I would not expect it to dissolve paper, you might
give consideration to using a mildly abrasive Tooth Paste
and a soft bristle tooth brush. Scrub in a circular motion.

I have not tried this my self as it just occurred to me, but the 
Toner Transfer is basically a plastic which I think should 
withstand the scrubbing for a lot longer than the paper fibers.

I suggest using a soft bristle brush because I think the bristles
would be more likely to flex and bend over instead of possibly
gouging into the edges of the traces and pads as harder, stiffer 
bristles may tend to do.

BTW there are starch based disolvable papers out there,
see my post on the subject "Water Soluble Paper " 

( http://tech.groups.yahoo.com/group/Homebrew_PCBs/message/11416 )