If the only problem I was having is to fill in an occasional pinhole,
I'd call it good. Given the amount of manual fussing you have to do,
that seems a pretty minor point.
I've been experimenting with this technique but have yet to get a
laminator becuase I've gotten reasonably good results from the iron
approach. It seems to me that there are a number of variables you
have to deal with. each one can ruin the process.
1) fusing temperature
1a) toner fusing point
1b) fusing time
2) fusing pressure
3) thickness of toner
4) quality and cleanliness of copper substrate
I think 2) is a huge issue in that there is fine line between too
much and not enough. I found that even modest pressure causes some
smearing of toner (and the widening of traces). Its my opinion that
little pressure is needed, you just have to ensure that the toner
makes contact with the substrate for a long enough time at the fusing
temperature. i.e., it has to melt and be in contact with the
substrate long enough. I've gotten good results with letting the
iron be all the weight needed. I also do not apply ANY lateral force
as that seems to cause smearing.
Since I print on an inkjet and then use a copier for my toner
deposition, I am able to control the amount of toner pretty well. I
tried a non-scientific range of toner densities and found that you
want it to be fairly thick, especialy for large ground areas. How
ever, the thicker the toner, the easier it is to get smearing. less
pressure is needed in that case.
It probably goes without saying but preparation the the board is
critical. I've gotten good results with a very fine emery cloth to
create a rough surface (i.e. significantly increase total surface
area to allow better toner bonding).
Toner fusing temperature is tricky because different toners have
different fusing points and it appears the substrate material type is
a factor as well. For example, ricoh has a lower temperature toner
to allow shorter warm up times for their printers. does anyone have
pointers to information on fusing temperatures for varous toners?
I've googled until my eyeballs hurt and found only scraps of info. I
may just have to try an experiment.
Phil
--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller"
<leon_heller@h...> wrote:
>
> >From: "joshdewinter" <joshdewinter@y...>
> >Reply-To: Homebrew_PCBs@yahoogroups.com
> >To: Homebrew_PCBs@yahoogroups.com
> >Subject: [Homebrew_PCBs] AHHH!!!! Thermography looking like a
better
> >option
> >Date: Wed, 11 Feb 2004 17:35:49 -0000
> >
> > I'm getting frustrated. I've tried all night (for several
nights)
> >to perfect my toner transfer process. I keep getting marginal
> >results. I started with an iron. Eventually, I got a laminator,
> >albeit a cheesy, low grade one.
> > My results are not production grade, and it's frustrating me.
>
> [deleted]
>
> You are probably using the wrong printer, some are better than
others at
Show quoted textHide quoted text
> toner transfer.
>
> Leon
> --
> Leon Heller, G1HSM Tel: +44 1424 423947
> Email: aqzf13 at dsl dot pipex dot com
> WWW: http://www.geocities.com/leon_heller
>
> _________________________________________________________________
> Find a cheaper internet access deal - choose one to suit you.
> http://www.msn.co.uk/internetaccess