>
> - To take out the toner when the pcb is finished it is much
> easier to use
> acetone (industrial or even of the kind the women use for removing the
> paint from the nails : more expensive) than grinding the pcb.

Acetone and similar hydrocarbon solvents will break down the pcb resin of
many glass and paper composites. That surface will then invite contaminants,
including whatever you washed off with it - a good reason why all the
packaged transfer systems suggest scrubbing.
>
> - It is very important to use the appropriate paper. Do not
> spare on the
> paper : with glossy photoprint paper the success is
> guaranteed. I can make
> pcbs with tracks going through 2 IC pads (2.54 mm distance)
> without too
> much trouble.
>
> - As a reference : stay with the iron (full power) over the
> pcb board face
> up
> covered with a piece of cloth 1.5 minutes, moving the iron so
> as to achieve
> a more uniform heating (not all the iron base has the same
> temperature) and
> strongly press the iron against the board. Do not stay too
> much time or you
> risk the toner spreading too much and getting tracks too wide.

As the toner heats more & more, the viscosity drops, allowing the pressure
from
the iron to spread it farther. If the temperature is controlled between 420
& 450 deg F.
and the pressure on the iron doesn't change, the traces should spreadless
than 5 mils.
How about movement of the transfer image while moving the iron?
I have done this w/o moving the iron (small boards only, of course) then
applying even
pressure with a small brayer to ensure good transfer.


>
> - To remove the paper it is better (according to my
> experience) to use very
> hot water instead of cold water. In a couple of minutes the
> paper peels-off
> without having to touch at it.

I think the cold water is intended to "set" the toner by cooling it rapidly.
But I'm sure hot water removes the paper better. I have done cold, then hot.
>
> >
> > For ease, nothing beats the iron-on transfer method.  You
> can use glossy
> > ink jet paper, laser print the layout on it and iron it onto the
> > copper-clad.  It takes a bit of finesse but once you figure
> it out you
> > can get pretty fine traces on there consistantly.

The blue stuff seems to be pretty reliable also, but nothing beats Advanced
circuits doing them 2 up for $28 US with silk and mask with real through
holes. Nobody on tis list can set up to do an iron on board for the
equivalent cost in time. I figured the last iron on board I did, at about
1.25 x 2 cost me about the equivalent of $750 in billable time. Now I will
only do thismethod when I have nothing else to do.

PS, thanks for the nice description & summary.

Chris
> >
>

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