Homebrew PCBs

On Sun, 21 Nov 2004 22:13:34 -0000, Dave Mucha <dave_mucha@...>  
wrote:

>
> Surface area and board material !
> When I got my T-TEch machine, it came with a couple sheets of 1oz dbl
> sided with a very white substrate.  the copper pealed off very
> easily.   So easy that it was easier to peal than to use the cutter
> to clear large sections of unused area.
> The FR-4 I used next was next to impossible to peal and the CM-1 I
> now use is very easy compared to FR4 but not quite as easy as the
> other stuff.
> Dave


Too right there!
FR4 seems to hold much better.
Maybe it depends on brand too, how the copper bottom side is prepared.
I had heard numbers at some point, quite impressive i remember, of force  
per area .. maybe
one can find them somewhere.

With connectors also consider the degrees of freedom. A single row 90\ufffd  
header might be pulled straight,
or levered to the side. using a 2-row makes it more stable.
Worst must be the idea with the screw terminals soldered to the edge. i  
can see myself breaking the pad
off with that. perfect lever angle, solid connection to wire, torque whith  
screwdriver, perfect edge to
start.... A two-row or d-sub on the edge seems solid compared to the screw  
terminal.


ST