As you've noted, you do need a steel edge.  Brass is too soft; I've 
never tried plastic, but I'm not surprised it got nicked.  Be careful 
if the rule has graduations on both sides.

For scoring, I use a regular #11 blade, deliberately dulled on a stone.
I've also ground a number of small chisels from old blades, for inside
cuts and delicate work.  This approach works well if you've got an excess
of handles--I had a lot of handles even before I took up paper modeling,
I've no idea how many now.  If you can cadge an old scalpel from one of
the med students, that works well (but of course you need new blades.)
The scalpel blades are thinner than X-Acto blades.

Rolling cylinders is straightforward, except for the very small ones, but
takes some practice.  For reasonably sized ones, start by drawing the
paper across the edge of the table to develop a curl.  Then switch to
pressing the paper between the palm of your hand and a suitable tool,
such as the handle of your knife.  Make sure your hands are very clean;
some people prefer to use a sponge or foam rubber backing for this step.
Smaller cylinders can skip the table edge and go straight to the forming.
Using a tool somewhat smaller in diameter than the final cylinder, press
the paper firmly with the tool while sliding the tool back and forth.
With some practice, you'll find you can get the paper to conform to its
final shape.  It sometimes helps to leave some excess paper on the part
along the edges; cut the cylinder to length before rolling, but leave
some on the sides, to be cut off after the cylinder is rolled.

Any smooth hard cylinder will make a suitable forming tool.  I've got
a couple of dowel scraps, sanded smooth, that I use a lot.  I also use
knife handles, pens, and anything else handy.  For very small ones, I
use hobby shop brass rod or tubing.

Very small cylinders are tougher.  I'm still working on this technique,
but I recently managed to roll some about 2 mm in diameter for the Oceanic
Hochseeschlepper I'm working on, so I'm beginning to get better at it.
There's a lot in the FAQ on the small cylinders.

For gluing paper, I've found nothing to beat Elmer's white glue, although
many people swear by 'Tacky glue'.  It works well for everything except
laminating.  I mostly use a double-gluing technique.  Spread a VERY thin
layer of glue on both surfaces and allow to dry--with a thin layer it will
dry in a few seconds.  Spread another very thin layer on one surface, 
position parts carefully, and apply pressure.  It will grab and hold as
soon as the pressure is applied, and you can work with the part almost
immediately--no clamping or waiting necessary.  The key is using no more
glue than necessary.  An orange stick and smooth jawed needle nose pliers
are good for applying the pressure.

For 4-year old hands, you might look at the Dover Easy-to-make line (p. 19
in the PMI catalog; sometimes available in local bookshops.)  They really are
easy, and they are pretty sturdy.  The firehouse held up for a year or so
under the ministrations of my 5-year old nephew (although I did have to add
some stiffening girders to the house after it got sat on.)

Only Fiddler's Green model I've built is Jaws (presently ensconced on your
sister's desk), although I notice I've got a mention on the web page.  I
ought to do some more--I'd really like models of the Harrier and Yak-38--but
I've not gotten around to it.  Chip Fyn has a really nice line of stuff
(but no ships :( ) and based on e-mail correspondence, seems a really nice
guy. 

While you're at Paper Paradise, check out some of the others.  They've also
got downloadable models from ModelArt, and Emil Zarkov does really impressive
work.

-- 
Steve Brown, N8HFI              browns@ee.eng.ohio-state.edu
	http://er4www.eng.ohio-state.edu/~browns
Card Modeling FAQ: http://er4www.eng.ohio-state.edu/~browns/card-faq/