Date: Tue, 18 Oct 2005 10:29:15 -0400
To: WSFA members <WSFAlist at WSFA.org>, WSFAlist at WSFA.org
From: "Mike B." <omni at omniphile.com>
Subject: [WSFA] Re:  REviewer's workshop
Reply-To: WSFA members <WSFAlist at WSFA.org>

At 04:07 AM 10/18/2005 -0400, ronkean at juno.com wrote:

>Don't sustitute pressboard for real solid wood, though
>lengthwise-laminated wooden boards are O.K., and they are available in 16
>inch widths.  Pressboard just isn't strong enough, and it's likely to sag
>or break under the weight of books, assuming 4-foot spans.

A 4' span even with Oak is probably too much if we are talking about 3/4"
thick and something more than paperbacks.  Standards say 36" for that.  To
get to 4' or more you need reinforcement of some kind or it will sag
eventually.

I'm not sure exactly what you mean by "pressboard"...there are several
artificially made sheet products that are often lumped under that term.
There's "particleboard", "chipboard" (also known as oriented strand board,
or OSB) and Medium Density Fiberboard (known as MDF).

Particleboard is often used in cheap manufactured furniture of the
"knockdown" variety.  It is the weakest of the three and is basically
sawdust glued together.  It is certainly not a good choice for shelves,
though it is used that way in some bookcases I've seen...usually laminated
with wood veneer.  If it ever gets wet it will swell and will not return to
it's prior state even when dried out.

Chipboard, or OSB, is used for subflooring and roofing.  It is made from
larger shavings of wood, glued together under pressure.  It's stronger than
particleboard, but fairly rough and not what I'd choose for shelving.

MDF is fine sawdust glued together under great pressure.  It is heavy,
smooth, fairly strong and takes screws better than the other two.  It can
make decent shelving, but not for large unsupported spans.  It gets used in
better quality knockdown furniture and things like table and counter tops
(under laminate).  It runs about $18/sheet (4'x8').  It machines easily
with carbide bits, but produces a lot of very fine dust when you do
so...and breathing this is not recommended so wear a dust mask.  I've used
it to make supports for UPSs and computers, and spanning 20" with a large
tower PC on it hasn't resulted in any sag so far (about a year and a half).
 MDF will also swell if it gets wet, though there are versions of it that
are more resistant to water.

Plywood can make decent shelves, but you need some way to hide the edges
(unless you like the look I suppose) and stiffening it in some way is wise.
 Adding a bit of solid wood glued and screwed to the edge does both, but
requires some tools to do properly (a pocket hole jig is very good for this
as it lets you hide the screws on the underside of the shelves, behind the
edge strip).  Other methods involve mitered joints using a bit of the same
plywood, glued on veneer edge banding, or edging of other materials, such
as aluminum (I have a shelf unit in the garage made from old store shelving
from a grocery store that was made this way...3/4" plywood covered in
Formica (tm) and edged with aluminum).

That reminds me...another method of making simple shelving is that unit in
my garage.  I made it with a hand drill in my first post-college apartment.
 Cut shelves to length (mine already were), drill a 5/8" hole in each
corner.  Run a piece of 5/8" threaded steel rod (hardware store, comes in
3'-5' lengths) through the holes, with 5/8" nuts placed above and below
each shelf at the heights desired (you can change the spacing with a wrench
at any time).  Put rubber caps (hardware store again...like crutch tips,
but smaller) over the lower ends to protect the floor, and perhaps over the
upper ends to reduce scrapes and make it look nicer.  This resulted in a 4'
tall set of 4 shelves that are strong enough for *me* to bounce on, and
stable if loaded properly (I have a 60lb mini-lathe on the top shelf at the
moment, with other stuff on the lower ones, but originally had a fish tank
on the top with books on the lower ones).  This think has lasted 25 years,
through 5 moves, and is as strong as it was the day I made it.  I got the
shelving for free from a closing store, the rods were about $1.50 each (4
needed), and the nuts (8/shelf) were about $0.30 each.  Costs may be twice
that these days though.

Pine is one of the more common solid woods used for shelving.  It is
relatively inexpensive (when compared to hardwoods like Oak or Walnut), but
it isn't all that strong in the forms you'll find it in around here in home
centers.  Fir is a bit stronger, and Spruce can be very strong with the
right grain (it gets used for things like musical instruments and airplane
wing spars).  Oak, Ash and Maple are all good choices for shelves, but
these are pretty expensive and the original idea was for cheap and easy to
make shelving so we can probably ignore them.

Hope this helps.

-- Mike B.
--

 To do is to be -- Nietzsche.
 To be is to do -- Sartre.
 Do be do be do -- Sinatra.