Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "dagmargoodboat" 
<dagmargoodboat@...> wrote:
>
> Robert wrote:
> 
> --- In Homebrew_PCBs@yahoogroups.com, Robert Hedan <robert.hedan@>
> wrote:
> >
> > > -----Message d'origine-----
> > > De : Homebrew_PCBs@yahoogroups.com 
> > > [mailto:Homebrew_PCBs@yahoogroups.com] De la part de 
dagmargoodboat
> > > Envoyé : juin 28 2006 22:59
> > > À : Homebrew_PCBs@yahoogroups.com
> > > Objet : RE : [Homebrew_PCBs] Re: Toner melting points, pt. 2
> > > 
> > > 
> > ...
> > > My board prep *was* slightly lax--stainless steel
> > > potscrubber, with soap, then Comet cleanser, towel
> > > dry--but it's robust enough to cut through the dull
> > > oxide and leave a mirror finish on the Cu.  Same
> > > procedure as used on the "perfect" trial board.
> > > 
> > > I'll post any fixes I devise.
> > > 
> > >   Thanks again Robert,
> > >   James
> > 
> > 
> > James,
> > 
> > I recommend at least either acetone or 90% + isopopyl alcohol to
> remove any
> > leftovers, and then wipe that dry.  I think Comet leaves a residue
> behind,
> > you might not have wiped it dry evenly between the 2 tests.  The
> last time I
> > used Comet on the sink, it leaves a very shiny and 'slippery'
> finish, it's
> > like a wax effect.
> > 
> > Robert
> > :)
> 
> 
> And Stefan suggested:
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@> wrote:
> >
> > I have not followed the thread, so maybe this is not a suitable 
answer.
> > 
> > Some printers use fuser oil on the fuser roller. maybe your toner
> surface  
> > is contaminated with that?
> > 
> > ST
> 
>   Thanks to both--what a nice group this is!  Here's my update:
> 
>   I've improved pcb copper preparation by rubbing to ensure complete
> removal of any cleanser films, and adding a wipe with isopropol 
alcohol.
> 
>   My earlier work measuring toner melting points suggests laminator
> heat is not a problem.  To double-check, and to eliminate questions 
of
> adequate pressure, I transferred the toner first with the laminator,
> then pressed hard with the edge of a household iron, working the 
surfaces.
> 
>   After soaking and removing the paper, I "flash fused" the 
remaining
> toner by heating the boards to ~180 C (360 F) for five or ten 
minutes.
> 
>  Despite the extra steps, results are not much different.  I
> transferred and etched 7 more boards.  Toner transfer isn't super --
> the 0.006" ((0.15 mm) traces show one or two gaps per board, which I
> touch up with a Sharpie marker, then bake to cure before etching.
> 
>   John Popelish's float etching method (floating the boards on FeCl
> ethant) worked a treat, saving over-etching in a number of places.
> 
>   If these were 0.010" lines I think the boards would be superb as
> they are; the defects that ruin a 0.006" trace would be much less
> important.  Fortunately these are tiny boards with only a few 
traces,
> so I can touch them up and still get good prototypes without too 
much
> trouble.  It is nerve-wracking though, to try and paint 0.008" /
> 0.006" / 0.008" space / trace / space rules with a Sharpie!
> 
>   Robert--since my tests transferring the toner patterns on Staples'
> Picture Paper leave gaps even on decorative foil when I try, I think
> this excludes copper surface prep. as a variable (though I did 
upgrade
> my procedure with some of your suggestions, as noted above).
> 
>   Stefan--yes, I still suspect (but cannot yet prove) something's
> wrong with the toner print, either dust, fingerprints, oil from the
> fuser rollers, or perhaps just from not using them immediately
> (oxidation?).
> 
>   I've a new test for toner adhesion, the "Rip Test."  After
> transferring the toner, I just rip the paper off, no soaking.  I
> discovered that, surprisingly, this left as much toner as gently
> soaking and rubbing.  I conclude that, once transferred, the toner
> grabs pretty well, and is tougher than I thought.
> 
>   So, that's the update.  Despite lack of a solution to my immediate
> situation, I'm encouraged that the toner's adhesion strength and 
ease
> of melting suggest that truly excellent 6/6/6 boards are possible.
> 
>   Thanks again for all the suggestions guys.
> 
>   Cheers,
>   James
>

James

Try the following to see if you can improve your toner adhesion:

Soon after you have your laser print and just before you wish to make 
the toner transfer, take a grease and lint free cloth and wipe the 
image with isopropyl alcohol. Only a minute amount of toner pigment 
will colour your cloth. Let it dry (a few seconds) and then do it 
again. No pigment should be seen to be staining the wet cloth this 
time. 
This should degrease the toner surface to some extent but not damage 
the image.
All the best.