|
|
Gene Larson's Shop Notes |
Return To Shop Notes Home Page
GLUES and ADHESIVES
|
|
Marine epoxies |
waterproof, good for coating and sealant |
|
Resorcinol |
waterproof |
|
Polyurethane & urea |
extremely resistant - extended immersion |
|
Type II PVA |
resistant - short exposure |
|
PVA & others |
do not use for high moisture applications |
===============
Some Comments
on Various Glues by Model Builders
Christopher
Morrison, long time NRG member,
made the following comments in his article on Catboats and his model of Pauline.
Small
brass stock was held to a master in order to file to shape. "Shellac is
nicer than cyanoacrylate for such work because it
is so quick and easy to undo with heat. One stick of furniture repair shellac
will provide several centuries worth of adhesive."
"The
3-inch block shells used in the rig were built up of pearwood
cheeks grooved for a strop and pearwood swallows.
These were glued together with the tiniest dabs of epoxy. The trick was not
filling the strop groove, since it is only a few thousandths deep and could
never be cleaned out afterwards. Epoxy is ideal for this because it does not
evaporate, and therefore does not skin over when used in minute quantities,
as water-based glues like Elmer's do. Consequently, mating pieces are
properly wetted with glue upon assembly, reliably producing sound
joints." (NRJ 39-4)
Erik
A. R. Ronnberg, Jr., former Editor of the Nautical Research Journal
and highly acclaimed professional model builder and researcher had the
following observations in his series of articles on "Steam Trawlers Come
to the Boston Fishing Fleet", in which he describes the construction of
the model of Surf of Boston.
"Cyanoacrylate glue was spotted at a given strake's ends
and middle, and yellow carpenter's resin glue was carefully spread between
the spots without touching them. The cyanoacrylate
acted only as an instant clamp to hold the strake firmly in place while the
carpenter's glue set." (NRJ 40-1)
"The
choice of glues for this work was also important for the model's longevity. I
have used Weldwood powdered resin glue for hull
glue-up since the late 1960s. When lifts are snugly clamped so there are no
gaps or slack seams in the glue joints, the bond is very durable and the glue
is compatible with most finishing methods. This is the only part of the model
where I use this glue; there are few other situations which allow the careful
clamping which is absolutely necessary to get a strong bond. Close contact
between the wood fibers of the joining surfaces is essential; only the
smallest amount of glue is needed to cement these fibers together. If the
glue forms a solid mass which separates the joining surfaces, a weak, very
brittle bond results and it doesn't take much of a shock, such as from
dropping, to cause the glue to shatter like glass.
"For
the vast majority of wood-to-wood joints, I use Elmer's yellow carpenter's
glue or its equivalent. This is the glue I used to apply the basswood
"out" strakes to the model, as its flexibility matches that of the
materials it is joining. In only a few cases, where great strength or
rigidity in a very small gluing surface are needed,
will I use epoxy glues on wood. They are extremely strong and tough, but very
rigid and unable to move with wood. I once glued up a large hull of obeche lifts (too soft - never again!) using epoxy resin.
After a couple of years, the lifts had shrunk, but the glue did not; every
glue seam stood out!" (NRJ 40-1)
In
applying copper wire to the hull to simulate rivets (3/8"=1'): "The
wire was roughened by drawing it through sandpaper,
the tip dipped in flat acrylic varnish, and pressed into a hole. Acrylic
varnish makes an excellent "glue" for this
purpose and has the advantage of being compatible with the gesso and
overlying finish coats of acrylic paint." (NRJ 40-1)
In
summary: "Wooden parts were glued to wood with yellow carpenter's glue;
metal-to-wood and metal-to-metal joints were glued with epoxy. In some cases,
mechanical fasteners were used." (NRJ 40-2)
A
remark by Dana Wegner, Curator of models for the U.S. Navy,
"Safety -- The David Taylor Model Basin used to use Weldwood
powdered glue (mentioned by Erik A. R. Ronnberg, Jr) exclusively and extensively for the tow tank models.
We always used it for gluing up lifts. If carefully mixed it was good stuff.
Several years ago the product was banned for our use by the Navy because the
dry powder was found to contain formaldehyde and is a carcinogen."
Dr.
John M. Bobbitt, award winner at
The Mariners' Museum, NRG essay winner, and long time NRG member states in
his article on "Wave, A Chesapeake Bay Pungy",
"I do not trust Cyanoacrylate glues and use
them only rarely to join very small parts under no torsional
stress." (NRJ 40-3)
===============
Quick Reference
on What to Use
For
a quick layman's listing of what glue to use for various applications go the
web site: http://www.thistothat.com/.
CATEGORIES AND TYPES
William
Tandy Young in Fine Woodworking (1) defines "glue" as being based
on polymers from natural sources (starch and protein such as rice or cattle
hide). These natural glues are generally reversible with the application of
water, a property desired by some archivists. "Adhesives" are based
on chemically synthesized polymers (PVA resins) and usually cannot be
reversed. There is generally no distinction made between adhesive and glue in
casual use.
There
are three major categories and many types of glues and adhesives (1) with
potential for common use by ship modelers, plus an "other" category
added by the author. These are discussed in detail within this article:
NATURAL
GLUES
NONREACTIVE
SYNTHETIC GLUES
REACTIVE
SYNTHETIC GLUES
OTHER
(added by author)
RATING GLUES
The
August 1999 issue of Consumer Reports (2) rates "household
adhesives" in a very brief two page article, but they have a direct
application to model building. Consumer Reports does not release
copyright on their published materials, therefore, the results cannot be
repeated here. However, an issue can usually be found in a local library, or
for a fee can be accessed on their web site.
PROPERTIES OF GLUES AND ADHESIVES
NATURAL
GLUES
Rice and Wheat
Pastes
Bond:
porous materials, i.e. paper, cloth & leather to wood.
Strength:
do not use to bond wood
Longevity:
poor unless preservative is added to inhibit fungal attack
Fish Glue
Bond:
wood to wood, natural materials, i.e. cloth, metal & bone to wood, grain
filler
Strength:
light duty bonding
Longevity:
becomes brittle with age
Hide Glue - an old traditional glue
Bond:
most materials to wood, edge and face gluing, & veneering
Strength
excellent, but avoid thick layers which become brittle
Longevity:
may become brittle with age
Casein Glue (made from milk) - an old traditional glue
Bond:
oily woods, veneering. Thick glue lines. Some gap filling
Strength:
excellent & creep resistant
Longevity:
poor unless preservative is added to inhibit fungal attack
NONREACTIVE
SYNTHETIC GLUES
Ethylene Vinyl
Acetate Glue (EVA)
Bond:
mainly woodworking for cross grain wood with expected movement
Strength:
little rigidity and creep resistance
Longevity:
affected by heat & moisture
Cleanup:
water
Polyvinyl
Acetate Glue (PVA) white and yellow
glues. (The term Aliphatic resin is meaningless (1))
Types:
White
- low grade craft/hobby/school, paper and fabric
Yellow - high grade professional & industrial
Bond:
- edge & face wood gluing, plastic laminates
Strength:
White
- adequate but low rigidity & creep resistance. Highly flexible, but
rubbery composition clogs sandpaper.
-
Will not take any strain so use it only for non-stress and non-load bearing
parts unless fasteners are also used.
Yellow
- higher strength, rigidity, durability & creep resistance - they are
comparable to epoxies, but fasteners are still desirable.
Longevity:
White
- low resistance to heat & moisture, and is shock resistant. Inside use
only. Freezing will ruin the glue.
Yellow
- High resistance & shock resistant
Both
will degrade in high UV light
Setting
time: short to medium grab time, but should be clamped for maximum strength.
Note:
PVA glues will adhere more than just wood, however, the bond will not be as
strong. The white (clear dry) glues can be used on transparent plastic items
such as canopies, windows, portholes, etc. without evidence. (3)
A
remark by Dana Wegner, Curator of models for the U.S. Navy, "In
concert with my report on lead rot, I would ask that model builders recall
that PVA glue and some brands of silicon sealant release acetic acid which
can be harmful to lead fittings in a stagnant environment."
See the NRG web site at: http://www.naut-res-guild.org/Reference/lead2.html
Contact Cement (recommend water based products due to toxicity)
Bond:
laminates & veneers
Strength:
no permanent structural strength, rigidity or creep resistance
Longevity:
poor moisture & solvent resistance, good heat resistance
Note
by Ben Lankford (Former NRG Director and Treasurer) in NRJ 14-3,
"Contact Cement is good for copper bottoms and also for sticking deck
houses down on decks when you do not want glue squirting out on the deck. Be
careful to line up first or you will wind up with a crooked deck."
A
remark by Dana Wegner, Curator of models for the U.S. Navy,
"Ben's (recommended) preference for contact cement for copper plating
would suggest that he has never had to reattach those little plates when they
flutter off the model in five or ten years. In our experience, except for
ease in application, contact cement is a terrible choice for copper hull
plating."
As
you know, you need a plan for applying contact cement in advance of applying
the copper. You can't work too much in advance, nor can you be too slow. The
smell can get you too. We have found that contact cement seems to dry up
between five and ten years after application. The actual time probably
depends on the brand, the technique, and the environment.
Author:
"then what do you use for hull plates?"
Dana
Wegner: "We use 3M adhesive
film for copper. (See below)"
Hot-Melt Glue
Bond:
edge banding sheets & for jigs and temporary projects
Strength:
very little
Longevity:
moisture resistant but no heat or solvent resistance
Note:
The woodworkers white stick hot melt glue can be used on bulkhead models (3)
REACTIVE
SYNTHETIC GLUES
Urea Resin Glue
Bond:
exterior wood joints, laminating, veneering
Strength:
very strong, rigid & creep resistant, especially two part products
Longevity:
may become brittle with age, especially lower grades
Setting
time: quite long
Products:
Cascamite, Aerolite
Resorcinol
Bond:
face & end wood bonding, veneers & laminations
Strength:
very strong, rigid & creep resistant
Longevity:
solvent & heat resistant
Note:
Highly visible joint due to red color
Note
by Ben Lankford (Former NRG Director and Treasurer) in NRJ 14-3,
"For gluing up lifts of models try Resorcinol instead of Weldwood Plastic Resin glue. Resorcinol comes in two
parts which, when mixed together, sets with an excellent bond and is
completely waterproof; it will not shrink, will not deteriorate in the can (Weldwood does), is red in color and is available from any
hardware store."
A
remark by Dana Wegner, Curator of models for the U.S. Navy, "Ben
Lankford's (recommendation on) Resorcinol glue is, indeed, the best
waterproof glue available. Those considering it should know that dry (cured)
resorcinol is usually considerably harder than the wood it adheres. It is
difficult to carve and sand lift models glued with resorcinol because the
glue joints are harder than the surrounding wood, usually resulting in raised
glue lines. Also hard Resorcinol is tough on edged tools and dry glue
fragments can damage your eyes."
Epoxy
Bond:
wood, veneers, laminations, metal parts to each other and to wood.
Strength:
excellent but relatively low heat resistance, even sanding heat. I prefer Devcon epoxy: the plastic steel, the short 5 minute, and
the longer setting two ton brands.
Longevity:
excellent.
Note
by author: Epoxy is a good sealer for porous woods, and for waterproofing
if marine epoxy is used. If the epoxy to be used as a "sanding
sealer" is too thick it can be thinned to the desired consistency with
denatured alcohol. (Too much thinning might effect
the bond to the wood and might induce cracking over time.)
Epoxies
come in various cure times, and it is generally accepted that the longer the
cure time the stronger and less brittle the bond. They also are available
various consistencies ranging from a thin liquid to a thick putty. The thick
epoxies are excellent for embedding propeller shafts and rudder tubes on
radio control models. I place car body fillers in the epoxy category and
recommend their use for many applications.
They
seem to be the strongest of the adhesives available. Color can be added to
them for fiber glass work, and they have advantages in solving many structural
bonding problems. They can be used to "glaze port holes.(3) They can also be used as fillers and for sealing wood
(vs sanding sealer).
Note
by Ben Lankford (Former NRG Director and Treasurer) in NRJ 14-3,
"Epoxy comes in two types, both useful. The first is the two tube type,
amber color when mixed. This is good for small parts, both wood and metal,
that require good strength. The second is the thick grey kind which comes in
large containers and is excellent as a filler and
provides a good glue bond at the same time, something you can not get with
regular wood filler. Though it sets harder than most woods, it sands
well."
Polyurethane
Bond:
wood, laminations, veneers, metal. Tight fit and clamping required, however,
these do expand on curing and fill in slight gaps quite well and they are sandable (Lloyd Warner, NRG Secretary).
Strength:
good strength with creep resistance & rigidity
Longevity:
not available
Cyanoacrylate
Instant glues (Super Glues)
Bond:
rapid bonds of small pieces of wood and other materials. Not for large pieces
Strength:
Very strong & rigid. Fair durability on small surfaces. Good in tension,
poor in shear
Longevity:
Good moisture & heat resistance. Poor solvent & shock resistance.
Will yellow & may degrade in UV light
Cyanoacrylates are available in various consistencies ranging from a thin liquid
for close fitting low porous materials with on gap filling capability medium
viscosity thicker "gels" for porous materials and some gap filling
capability.
They
are also available for purposes ranging from wood, plastic, metal, general
purposes, etc. Some can attack various coatings and materials.(3) It is advisable to always test the compatibility
before using on the project.
Do
not use CA glue in projects that come in contact with water.(4)
Note
by author: This glue is not recommended for model work by certain builders.
It has been suspected to have a chemical reaction with copper and brass. In a
Shop Note by Peter E. Demarest, he states in part, "Every (brass)
hook on the model that was in touch with the cyanoacrylate
was in some stage of failure, and only those hooks were affected" (Nautical
Research Journal, Volume 40, Issue 2, June 1995)(5).
Dana
Wegner was asked what glues are on
hand in the U.S. Navy Model Shop. He replied, "white PVA and cyano". However, Michael Condon, Ship Model
Conservator in the Model Shop explains, "In response to Gene's question
about why we have CA in the shop if we don't allow it in our specifications.
We use this adhesive out of necessity, on occasion, when speed and work
volume become considerations. Many times we are in a situation where we are
forced to fast-track a project or perform work in the field under time
constraints. We consider our use of CA to be prudent because we have had
extensive experience with it and are familiar with its shortcomings. So, we
only use it in situations where we are confident in its abilities. We avoid
reliance on its structural strength, especially over the long haul, by
extensive use of fasteners and by relieving strain at the attachment site.
Typically, we will only use CA for the formation of fillets or in an attempt
to add girth and dimension to a detail. CA is somewhat hygroscopic, so a
vapor barrier is very important to its longevity. Climate controls and a lack
of exposure to organic solvents is critical to this
material's success. Furthermore, when we use CA we know its exact location on
the model so we can closely monitor it. We discourage the use of CA on
contract models because we cannot control its exact application. We choose to
make our lives simple and "just say no."
A
word of warning by Charles O. McDonald, former Editor of the Nautical
Research Journal, in Volume 33, Number 2, June 1988, "Some topmast
futtock shrouds I had worked on just before abandoning the project (to become
Editor) and had secured with cyano-acrylate to
prevent their distorting the lower shrouds when their lanyards were rove
became entirely crystalized despite being linen
cord. When I resumed work, they broke like thread made of glass. DON'T use CA
anywhere around rigging! It is handy for many things, but not that!"
In
addition, its longevity has not been proven conclusively, and to my knowledge
no conservators recommend its use. When used in rigging ships the glue makes
the lines very rigid and susceptible to breakage. For porous woods such as
basswood (lime), mahogany, etc., it must soak in and build up sufficient
material to create a bonding surface. An initial application, which is
allowed to set, helps to seal the pores, and the next application will hold.
However, the super glues make the wood brittle. The absorption effect
inhibits the use of stains and natural finishes on wood much more that the
other adhesives that only fill the joints.
However,
the super glues have been very popular with the resin kit builders who
concentrate on 1/700 and 1/350 warship models. The glue is especially useful
in bonding the very fine photo etched brass fittings including the ship's
railings. There apparently has not been a problem identified to date with the
use of the instant glues on the models. Time will have to be the judge.
CA comments by
former NRG Director and long time member John Fryant
(Riverboats & Tug boats plans service)
"Its
too bad the Consumer Reports article didn't test some of the leading hobby CA
glues, such as Zap, made by Pacer Industries, or Insta
Cure, made by Bob Smith Industries. I've used both these brands extensively
with very satisfactory results.
"I
have found that very good metal to metal joints can be made with CA providing
that the metal pieces are absolutely clean. I usually sand the joining
surfaces with 220 grit paper, then wipe them clean
with a tissue or cloth.
"A
far as using CA as a filler, plastic modelers do
this all the time. I constantly read kit reviews in FSM where the author uses
and recommends medium or thick CA as a filler around
poorly fitting parts. I doubt it would be good for this purpose on a wood
joint, as the cured CA is harder than the surrounding wood, therefore making
sanding difficult.
"As
for the permanence of CA, that's where I disagree with most critics. I've
been using CA for about 21 years now on both personal and contract models. I
have yet to hear of one of my museum models falling apart. Also I've used CA
to glue paddlewheel parts together - hundreds of little plastic bolt heads
and wire stirrup bolts, all glued to plywood arms and bucket planks. These
are working paddlewheels for R/C models and are subject to constant immersion
and drying off, changes in temperature and humidity, etc. One of these wheels
has been in service for about ten years and nothing has fallen off ( yet!) Of course, all of these parts are painted after
assembly, which waterproofs the glue joints somewhat.
"Of
course, time is the only thing that will tell the tale both for acrylic
paints and CA glues, which become an acrylic plastic when they cure. None of
us will be around 500 years from now to see if those paintings and models are
still intact. I guess when that time comes we will be either praised or
condemned for using acrylic products."
Long time NRG
member Phil Krol states:
"Cyanoacrelate glues will continue to be used by modelers
in spite of their shortcomings. Two brands absent from the test list commonly
found in hobby shops are ZAP from Pacer Technology
and Bob Smith, who puts the hobby shop label on the bottle. My personal
preference is Zap. The Bob Smith formula seems to have more surface tension,
and doesn't flow into a joint as readily. You may want to consider mentioning
the use of accelerator for CA and also debonder.
"Another
application technique for CA is putting a capillary micro dropper on the
bottle spout. These will dispense micro drops directly from the bottle in a
controlled fashion, one micro drop at a time. I used to be able to buy them
on a card, 6 for $.50, but when my supply was running low, I found they were
no longer available. I now make my own from teflon
tubing by drawing them out in a flame just enough to soften the teflon, but not burn it. Perhaps this may be more than
most modelers would want to get into."
Dave Judy, an outstanding warship model builder in the
Washington Ship Model Society states:
" I
prefer the CA glues but also use epoxy in some applications. The
Also,
please see the comments under "Longevity" at the beginning of this
article.
OTHER (added by author)
Adhesive Film
This
is the 3M type adhesive strips that has a peal-off
backing on each side. It is adhesive only, without a plastic carrier such as
Scotch tape has.
Bond:
for most any smooth surface contact. Especially good for copper hull plating.
Strength:
excellent bond if there is a close contact made.
Longeviety:
lasts much longer than contact cement. It has been used for many years.
Dana
Wegner says, "We use 3M
adhesive film for copper. We have considered using the film in a few cases
where we might use glue. But we have not tried it yet. Some likely areas
would be like joining small superstructure elements to decks, attaching gun
mounts or gun tubs to decks, etc. Before using the film for copper, we had
good luck with old PVA too. (Believe it or not, PVA has some metal to metal
bonding capability.)"
The
product is 3M Hi Performance D/C Polyester Tape with Poly Coated Liner;
Product number 9500PC. It comes in rolls 3/4 inch wide by
I
did locate a retailer named Gard Distributing Co.
who will sell by the roll. The price is $12.64 per roll plus shipping.
Compared to the price that 3M quoted, Gard's price
is reasonable. The address is:
Gard
Distributing
6981
NW 42 Street
Tel
305-592-6920
I
dealt with Gard by phone and ordered using a credit
card with no problem. They shipped via UPS. I had located several other
distributors, some thru 3M and some by other means and none but Gard would deal in less than case lots. I suspect that
they did not stock the tape and would order from 3M to fill a case lot order.
Gard seems to keep the stuff on hand.
Although
3M does not want to retail this stuff, if you call them at the above 800
number they will send you a sample roll containing
Plastic
(polystyrene) glues
Bond:
mainly plastic to plastic. The plastic is partially dissolved by the glue and
the bond becomes permanent - similar to a weld
Strength:
if properly made the bond is as strong as the original plastic, however,
certain glues of this type contain chemicals that remain in the joint and can
cause brittleness with time.
Longevity:
no known effects from aging
Note:
There are generally two types of plastic glues. The type
available in tubes contain a plastic base and a solvent. When set the
solvent has evaporated the base remains. The liquid cements come in a bottle
and contain only the solvent. Many model builders recommend the second
type.(3)
Fiberglass
resins - both epoxy and polyester
Bond:
fiberglass molded parts to each other and to wood but bonded surfaces must be
sanded. Good sealer for porous woods and for waterproofing. Can be used in
place of sanding sealers.
Strength:
high strength if mixed properly but less than if fiberglass were imbedded in
the resin.
Longevity:
brittle but no known aging effects.
Solvent glues the basic "ageless" model building glues.
Bond:
plastic, wood, ceramic
Strength:
not too good, but flexible
Longevity:
Not available, but have been used for many years. Shrinkage during the cure
process may be a problem
Caution:
notable for the toxic and flamable fumes they
produce. Use ventilation
A
remark by Dana Wegner, Curator of models for the U.S. Navy,
"Longevity. Ambroid glue, similar to old
"Duco" cement, is celluloid based. Dry or
wet it is flammable and potentially explosive. It usually has poor longevity.
A dinosaur from the age of "airplane glue."
Note
by Ben Lankford (Former NRG Director and Treasurer) in NRJ 14-3,
"Ambroid is good only for sticking two
lacquered parts together, even though many ship model builders swear by it
and use it for many tasks. However, I still think it should stay with the
model airplane builder."
Goo
Comments by former NRG Director and long time member John Fryant (Riverboats & Tug boats plans service)
"Goo is marketed by Walthers and
aimed mostly at the model RR market. The labeling on the tube proclaims this
to be 'a rubber based adhesive'; beyond that I don't know what it's composition is. It has been around for at least 45
years and is one of the best adhesives for joining dissimilar materials.- brass to wood, for example. Goo
is very much like Goodyear Pli-O-Bond, which I
haven't seen for awhile.
"One
of the best techniques for joining metal to wood with Goo
is to heat the metal part after the pieces are joined. When you see the Goo bubble out from the joint remove the heat . After it cools you will never be able to separate
the pieces!"
A
remark by Dana Wegner, Curator of models for the U.S. Navy, "John
Fryant's (recommendation on) Goo
was always one of our favorite "temporary" glues (it doesn't last
very long) but it was also banned by our safety office because of one of the
solvents in it. I cannot recall which one gave them a problem. It was a long
time ago."
"Varnishes"
Although
not conventional, for small parts and special applications clear acrylic
(flat or gloss coat, Future Floor Wax/Johnson's Kleer/etc.)
or lacquer/enamel based clear coats can be used. The acrylics have the
advantage of drying quickly and quite flat (especially Future).
Silicon bath
sealant (caulking)
This
material can be used in radio control boat applications where operating parts
need to be fixed inside the model but future removal may be necessary, such
as for ballast, radios, and motors.(3)
Special
recognition and thanks -
to the following persons who made contributions to this article and who
provided suggestions and changes:
Dana
Wegner, Curator of Models, U.S.
Navy, and his associates: Colan Ratliff
and Mike Condon, David Taylor Model Basin, Carderock,
Maryland
John
Fryant, A
former Director of the Nautical Research Guild, Owner, Plans Service,
Lloyd
Warner, Nautical Research Guild
Secretary, Owner, Warner Woods West,
Phil
Krol
Dave
Judy
More detail can
be found in the following sources, most referenced above:
REFERENCES
1. Fine Woodworking magazine, January/February 1999, "A working
Guide to Glues" by William Tandy Young. Copyright release is greatly
appreciated.
2. Consumer
Reports, August 1999, "Stuck on Glues".
3. Marine Modelling International, "Adhesives for Marine Modelling", by Ian Williams, November 1998, Traplet House, Severn Drive, Upton-upon-Severn,
Worcestershire WR8 0JL, England.
4. Wood Magazine,
"Easy Reference Guide to Woodworking Glues", August 1998, Better
Homes and Gardens, 1716 Locust Street, Des Moines, IA 50309-3023
5. Wood
Magazine, "Ask Wood", October 1999. ibid.
6. Nautical
Research Journal, published by the Nautical Research Guild, various
issues.
7. Fine
Woodworking magazine, September/October 1992, "Adhesives for
Woodworking" by Chris Minick.
Copyright (c),
August 1, 1999
Note: I am liberal in releasing
copyrighted material for various purposes when requested, however, be aware
that this article contains material from another publication, included here
with permission.
Return To Shop Notes Home Page