Re: A note on PC boards, double and single sided.

Brad Thompson

Harvey White wrote on 1/5/2021 8:55 PM:

Printed circuit boards are generally made with one of two materials (there are others), either a paper epoxy (FR-3) or a fiberglass epoxy (FR-4).  There are others, but these are most common.

Paper epoxy (FR-3) has a lower temperature tolerance, is not as mechanically stable, can be burnt easily, and is constructed of paper and epoxy holding it together.  You see it in a lot of commercial (expensive or not...) equipment.  It is mostly brown...
Older imported electronics used a phenolic-based laminate-- typically medium to dark brown
and liable to losing its traces when the repairer applied too much heat. Oh, and when overheated
it smelled like warm horse s*it.


Brad  AA1IP

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