Homebrew PCBs

Here is an interesting piece of related information:
A lot of years ago one major company, that I am not allowed to mention, was
eyeletting double sided PCB for best reliability since the plated through
holes sometimes were not so good in the beginning.

Originally they used simple split eyelets but then later the "improved" true
tubular eyelets with a rolled edge were implemented.  They caused a lot of
reliability problems!

When the PCBs were going over the soldering wave, the solder was properly
wicked up in the tubular eyelet and the component leads were properly
soldered but the solder did not reliably creep over the top rolled edge and
solder the eyelet to the top foil.  The old split one never had that problem
since it was partially open.

That brings the question: Why reflow the eyelets first?  Why not solder them
together with the leads in the holes?
Bertho
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From:  Stefan Trethan     Sent: Saturday, July 05, 2008 14:54
I most definitely remember reading somewhere that a completely "dry"
iron (free of any solder) is to be used to reflow eyelets, else the
solder will close the eyelet center making it impossible to use for
component leads later.
I do not remember where exactly i read it, or which brand of eyelets, etc..

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