I used to use the score and snap method (IMO score and mutilate) with different results.
If you score deep enough, the break is OK. However you must score almost right through the material.
If you don't score enough, some layers rip and some break, resulting in a really horrible edge, and a couple of mm of material which is useless as it's been quite damaged.
In all cases you can easily clean the edges up with a file and get them really nice.
However all this is a lot of trouble, the 2nd best thing in my opinion is a hacksaw. You may not get a really straight cut but it will go much faster and easier than the snapping method.
You can clean and straighten the edges with a file afterwards, and it's easier because there's less of a horrible edge to clean up.
I don't use either of these methods any more though. I came across an idea on a forum and I've been using it ever since.
It requires a drill press, but if you're making PCBs you probably already have one. You buy some of the cutter\router bits used for cutting boards on CNC machines. You set one up in your drill press and also set up some kind of fence to run your board along.
It's a little fiddly at the start, and if you do something wrong you will break the bit - but given some practice it's pretty good, and much faster than the score\snap idea.
--- In Homebrew_PCBs@yahoogroups.com, Leon Heller <leon355@...> wrote:
>
> On 17/11/2011 15:43, DaveC wrote:
> > This stuff is TOUGH! I scored with a utility knife, through the
> > copper and well into the fiberglass. When I bent it over the edge of
> > a table, it bowed a lot before finally breaking.
>
> I use CEM-1 paper/fibre-glass laminate. It's ∗much∗ easier to cut and
> drill than FR4.
>
> Leon
> --
> Leon Heller
> G1HSM
>