Model Forum / Radio Controlled / Air Models / January 2009

Get or make a _really flat_ building board.  I use a piece of plywood for
a base that I check with a straightedge and level, and shim to my bench
to assure flatness.

Get some _really square_ squares.  I was fortunate enough to score a
bunch of brass weights for a full-size aerospace application that happen
to be machined square -- they're square enough that I can sit 'em on that
flat building board and they give me a vertical reference, and heavy
enough that they stay put.

Come to think of it, cheap 1-2-3 blocks from a machinist supply (like
Enco Tools) would be the bee's knees for this sort of thing.  I dream of
getting a machinist's granite slab for building.  It's kinda hard to put
a pin into, but oh boy is it flat and rigid.

Well, the guy who taught me my first tricks (Phillip..never call him
Phil...his name was Phillip,
even to us kids) taught me to build on a ceiling tile. Those acoustic tiles
that look like they're
made from shredded, grey cardboard. Place it, finished side down, using
double sided tape, on a piece of 3/4" plywood cut to size. Pin the plans to
the tile and cover the plans with Saran Wrap.

Once he found out that my dad was a machinist, he was thrilled to death and
told me that most
of my problems were already solved. Before cutting out any bulkheads, mark
vertical and
horizontal lines on every piece, to be used as ledger references during
building. Nothing earth
shattering, just the prep work that an impatient kid would overlook. To make
a really long
story short, he taught me how to ask my busy, overworked dad for help and a
lesson in basic
shop setup and job prep.

One thing that struck me as strange was when he told me to prepare every
piece for the wings
and horizontal stab and weigh them all before even starting assembly.
Take the spars, leading and trailing edges, ribs, hinges, etc. for the left
side, and take the same
parts for the right side...and weigh them on a balance scale...to be sure
that one sides weight matched the other sides weight.  If they didn't match,
start swapping parts side-to-side to see
if a balance can be achieved. Only after that should parts be trimmed/sanded
to achieve balance.
He also taught me about balsa grain, density, and stiffness. As a kid, that
was something that
never occurred to me, but with a small model, it's something that's very
important.
Start balanced, finish balanced.

Another trick he taught me was to chech for runout on the spars and fuselage
stringers.
Spray a stringer with water, wait a while and see if it twisted while wet or
after drying. If it did,
replace it with one cut from a nice straight-grained piece of balsa.  In
other words he told
me to expect to throw away about 30% of a Guillows' kit balsa and replace it
with
lighter/straighter/stiffer where needed.

Phillip showed me how to use modeling clay as weight to hold things down
flat on the building board
while the glue dried, how to weight/pin down a wing while the tissue is
being applied and drying...

Basically, just plain ole'good building practice. Nothing earth shattering,
just the basics.

The biggest lesson:  patience, plain and simple. And, he taught me how to
talk to my dad.

Geezer

When I built my building table, I framed it with 1x4s and used a strait edge
and plane to level the frame before I put on the 3/4" MDF top.  I have a
piece of 1/4" plate glass that I actually build on.  The plans go under the
glass where they are easy to see and don't move.  As long as I look straight
down on them, they are easy to use.  The glass is flat and any glue that
gets spilled comes off with a razor scraper.  I have been using painter's
tape to hold things in place on the glass, but the modeling clay sounds like
a great idea I'll have to try.  As for vertical squareness, I used my chop
saw to make some 45 and 60 degree triangle blocks out of 3/4" oak stock.
They will stand on edge and 2 will hold things vertical while the glue
dries.