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Subject: Re: [Homebrew_PCBs] Re: toner questions

From: Stefan Trethan <stefan_trethan@...>
Date: 2004-05-22

> I came across a paper that will allow the toner to stay on it as long
> as you don't breathe too heavy. It will come off 100% with an iron,
> but the questions I have regarding all the reading I have done is as
> to pressure.
>
The coming off 100% is NOT a problem.
even with cheap photo paper there is no toner left at the paper here.


> It seems that I always have open specks in the print. It also seems
> that heat and pressure will force the toner together to cover over
> those little gaps.

Yes, pinholes, or more like nailholes ;-).
I have them to if the tracks get too wide.
It is because my printer does very poor toner density, not uniform etc...

solutions:
good printer
thinner paper.
c) manual touchup.


> A clothes iron will get the heat, but not the pressure. My next
> attempt is to get it hot and transferred and then use a roller to get
> the pressure.

Too much pressure is no good, it flattens out the tracks and you get
inconsistent
width. you need uniform pressure.

> I can see why the rollers are gettting high praise.

Because it is uniform and repeatable, not because you get more pressure.
I actually had to reduce the spring pressure quite a high amount to
prevent spreading.
Now you can see the tinyest isolation gap between 2 tracks 2 pixel
(6,66mil) wide,
spaced 7 mils. Before reducing the pressure i had too much spreading.

the pinhole problem was not increased, of course the spreading did lessen
the effect but
it greatly reduces quality.


gentle does the trick, not much pressure is needed

ST