34 MODEL AVIATION
by R.A. Benjamin
1
A golden-oldie
covering that’ s too
good to go away
Secrets
of
Left: Tools of the trade. Along with the Comet Aeronca
C h i e f f u s e l a g e r e a dy f o r c ov e ri ng i s a b ig j a r of
n o n tau tening c lear n it r at e d o p e and brush, a water
spray bottle, a sheet of silkspan, and an aileron that the
author has already covered.
SILKSPAN IS A unique variety of tissue
paper made from carefully selected plant
fiber. It’s the stuff from which teabags are
made. At roughly the time World War II
was fought, model builders got their hands
on some of this material and discovered
that it made an excellent covering for their
airplanes.
I’m uncertain who came up with the
term “silkspan,” which is marketed under
the name Modelspan, among others. But as
the name implies, the material is closer in
durability to silk—the gold standard of
model airplane coverings—than the finergrained,
more delicate papers that
aeromodelers have always called “Japanese
tissue.”
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:48 PM Page 34
May 2011 35
Above: Fold the loose section of covering out of the way, and
dope the edges of the structure partway along the span.
Left: The damp silkspan has been laid in position, and the
author presses, pats, and gently stretches the material to get
it flat and smooth.
Left: Learning to press and pull with your thumb and
forefinger is one of the key skills to working with silkspan.
Dope, stretch, press, and pull some more, the rest of the way
out to the wingtip.
Above: The process doesn’t always work the first time. Lift
any edges that don’t stick, add more clear dope, and then
press and pull some more.
Above: The inboard end of the left wing rests on the sheet
of silkspan that has been cut to size to form the bottom
surface covering. Leave at least this amount of extra
material around the edges with which to work.
Above right: This is the top surface, but that’s okay. The sheet of
covering has been water-sprayed, laid smoothly in place over the wing
panel, and then folded back to allow the author to dope the first
section of the structure to which he wants the silkspan to adhere. It’s
usually best to begin at the wing root, as shown.
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:55 PM Page 35
36 MODEL AVIATION
Where the covering goes around a sharp curve, you can slit the
edges into a fringe. The dope will hold each little section in place
more easily.
It’s easy to use a sharp blade to trim overhang on a flat surface
such as this. Practice will teach you to make a single, clean cut
through the covering without slicing into the wood.
When a structure section such as this wingtip lies in a plane of its
own, it might be easier to cover it as a separate piece. The
silkspan has been cut to size, dampened, and set in place, with
dope only on the rib at the top. A well-trained thumb is a big help.
This is the beginning of a double overlap. Never pass up the
opportunity to use that method; leaving open balsa edges throws
away potential structural strength and makes finishing more
difficult.
See the Rest of the Build Online!
We only had room to show you step-by-step pictures of the
wing. You can see R.A. Benjamin’s techniques for covering
the fuselage and tail sections on the Model Aviation Online
site, in the Exclusive Online Features section. MA
—MA Staff
Sources:
Model Aviation Online
www.modelaircraft.org/mag
For the little 1- or 2-foot-wingspan stick-and-tissue rubberpowered
models that were built in WW II times, Japanese tissue was
the best choice. It was usually included with any kit you might be
lucky enough to get.
For models spanning 3-4 feet or more, the extra strength that
silkspan provided made it a better choice than Japanese tissue. Real
silk was best for huge models, especially FF or CL gas-powered
aircraft, but it cost four to five times as much as silkspan and
demanded that you use more dope to seal it and build a good finish.
In the mid-1950s, when I became aware of silkspan, a 2 x 3-foot
sheet cost 15¢-25¢ at a hobby shop, depending on the weight
grade/thickness you wanted. It was good stuff.
From the end of the war through the 1960s, almost any mediumsize
model kit you could find had one or more sheets of silkspan
tucked in with the various sheets of balsa or rolled up with the plans.
You couldn’t call yourself a model builder if you couldn’t use
silkspan.
It’s still good, but these days hobby shops (both walk-in and mail
order) offer an impressive range of iron-on products that are
designed to seal balsa surfaces, cover “open” structures such as
wings, and put a color finish on your aircraft at once.
There’s no shortage of well-meaning experts who will assure you
that products such as silkspan are too hard to bother with anymore.
And it’s no surprise that good ol’ plain silkspan can get lost in the
glitter of all those guaranteed-to-be-shiny colors.
These one-step covering materials fall into several categories
Photos by the author
05sig2.QXD_00MSTRPG.QXD 3/23/11 11:30 AM Page 36
May 2011 37
Fold the loose covering back, and dope the remaining
edges.
You can trim the silkspan along the back side of a curved surface,
such as a wingtip, using a sharp blade and a delicate touch. Don’t
cut the wood!
This is the back side (top surface) of the wingtip. Get plenty of
fresh dope on the places where the silkspan is going to stick.
including Mylar film, polyester film, and synthetic fabric, and all
of them transform a series of tasks—that had to be completed
before you could fly your model—into one operation.
What’s wrong with that? Maybe nothing, depending on what
you want.
All iron-on coverings are quick to apply, relatively light, and
strong enough to stand up to plenty of real-world use. But all are
susceptible to sagging, wrinkling, and seam slippage in time.
It’s almost impossible to hide the seams and just about as
hard to get paint of any kind to stick reliably to iron-on covering.
There is no good way to cover concave surfaces such as wingroot
fillets with the material, and no matter what you do it looks
like exactly what it is: high-tech plastic wrap.
It’s similar to comparing a durable formed-plastic table and a
hand-crafted hardwood desktop. Both do their intended jobs
well, but each conveys a different message.
If I have your interest, read on. I will take you through an
introductory course in learning the secrets of silkspan. I am
presenting the lesson as a photo essay.
I’m using a real vintage design as the subject. During the late 1940s
What Is Dope?
It’s a paint product, similar to lacquer, that for a long
time was the only practical sealer and finish base for fabriccovered
full-scale and model airplanes. Many alternatives
have appeared on the market in recent years, but there are
still some things that dope does best, one of which is to use
with various paper-based materials to cover model aircraft.
As far as we are concerned, there are two kinds of dope:
cellulose acetate butyrate and cellulose nitrate. “Butyrate”
is the kind aeromodelers have used for decades, because it
is fuelproof (resistant to the alcohol in glow engine fuel).
“Nitrate” dope was around first, but it fell out of favor in
aeromodeling because glow fuel turns it into a gooey mess.
The problem is that butyrate doesn’t dry as soon as you
might think, and delayed shrinkage can distort model
structures months after finishing.
Moreover, nothing much sticks well to butyrate dope
except more butyrate dope, which limits your options.
Nitrate dope appears to dry after several hours or fewer,
and it really does. A nitrate dope base is stable and won’t
sneak up later and warp your wings.
You can also use nontautening nitrate dope, which
won’t shrink a covering any tighter than it was when you
put it on the structure.
Almost any other kind of paint product you can think of
sticks to nitrate dope. You can finish over it with more
nitrate, butyrate, enamel, epoxy, acrylic, or whatever else
you might want to experiment with.
If you are using electric power, the fuel issue goes away.
It’s good to remember, though, that the truly fuelproof
finishes, such as epoxy and urethanes, stick to a nitrate dope
base way better than they do to butyrate. MA
—R.A. Benjamin
05sig2.QXD_00MSTRPG.QXD 3/22/11 1:01 PM Page 37
and all through the 1950s, the 54-inch-span
Comet Aeronca Chief was available as a
classic rubber-powered FF stick-and-tissue
printwood kit.
“Printwood” meant that all parts, such as
wing ribs and fuselage formers, were cut to a
pattern printed in black ink on sheets of the
requisite thickness of balsa. You cut out each
part in turn with a razor blade or one of those
pointy model knives, if you could afford it
back then. Whether the parts would fit or not
was up to you.
If you can find an original printwood kit
today, you will probably have to pay a
collector price for it. I used a replica laser-cut
short kit with an exact copy of the old plans
from Tom Martin Radio Control.
I did extensive modifications to turn the
Chief into an electric-powered RC model. I
added ailerons, spars, fuselage stringers, and
scale dihedral, along with many details, but
my Comet Aeronca is still a nearly perfect
example of the art of covering with silkspan.
We are ready to cover the airplane, but
there are a few things that need to be checked
one more time before we begin cutting those
nice white sheets of silkspan into workingsized
pieces.
All structural work must be complete. All
power and control-system components must
be in place and tested. You can remove some
or all of the equipment while covering and
doping, but after you have done a beautiful
38 MODEL AVIATION
For further information, details, and pricing, contact
Zurich International, 9418 Snow Lake Place, Elk Grove, CA 95758
www.extremeglaresunglasses.com • [email protected] • 1-800-533-5665 • 916-691-6467
International Place Grove
See Better, Fly Better
with No Sun Glare!
The Best Sun & U.V. Protection
in the World!
Available in “fi t over style”
and Fashion “Pilot” Style.
“Extreme Glare” Technology
now made in Prescription
Lenses with outstanding
glare protection
job of finishing the fuselage is not the time
to discover that you can’t get the elevator
pushrod supports in place without cutting a
hole in something.
Various trim bits such as air intakes,
wing fairings, etc. might be designed for
mounting after covering. You’ll know it
when that happens.
Sand everything again. Every rough
spot, glue lump, or carelessly rounded edge
will show through the finished silkspan. Get
those things right while you have the
chance.
Dope the entire structure. Get at least
one wet coat of whichever variety of clear
dope you are using onto every structural
surface you can reach. This helps seal out
moisture and will impart a bit of resiliency
to the airframe, while sealing the wood so
that the dope you use as a covering
adhesive won’t be soaked up too quickly.
Sand every bit of structure that will
come in contact with the covering with
320-grit or finer abrasive paper. This will
help prevent snagging and tearing the
silkspan as you cover. It wouldn’t hurt to
give those contacting surfaces another coat
of clear dope and another careful sanding.
Now you are ready. You will find each
step of the process illustrated in
photographs, with relevant instructions in
the captions.
Edition: Model Aviation - 2011/05
Page Numbers: 34,35,36,37,38
Edition: Model Aviation - 2011/05
Page Numbers: 34,35,36,37,38
34 MODEL AVIATION
by R.A. Benjamin
1
A golden-oldie
covering that’ s too
good to go away
Secrets
of
Left: Tools of the trade. Along with the Comet Aeronca
C h i e f f u s e l a g e r e a dy f o r c ov e ri ng i s a b ig j a r of
n o n tau tening c lear n it r at e d o p e and brush, a water
spray bottle, a sheet of silkspan, and an aileron that the
author has already covered.
SILKSPAN IS A unique variety of tissue
paper made from carefully selected plant
fiber. It’s the stuff from which teabags are
made. At roughly the time World War II
was fought, model builders got their hands
on some of this material and discovered
that it made an excellent covering for their
airplanes.
I’m uncertain who came up with the
term “silkspan,” which is marketed under
the name Modelspan, among others. But as
the name implies, the material is closer in
durability to silk—the gold standard of
model airplane coverings—than the finergrained,
more delicate papers that
aeromodelers have always called “Japanese
tissue.”
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:48 PM Page 34
May 2011 35
Above: Fold the loose section of covering out of the way, and
dope the edges of the structure partway along the span.
Left: The damp silkspan has been laid in position, and the
author presses, pats, and gently stretches the material to get
it flat and smooth.
Left: Learning to press and pull with your thumb and
forefinger is one of the key skills to working with silkspan.
Dope, stretch, press, and pull some more, the rest of the way
out to the wingtip.
Above: The process doesn’t always work the first time. Lift
any edges that don’t stick, add more clear dope, and then
press and pull some more.
Above: The inboard end of the left wing rests on the sheet
of silkspan that has been cut to size to form the bottom
surface covering. Leave at least this amount of extra
material around the edges with which to work.
Above right: This is the top surface, but that’s okay. The sheet of
covering has been water-sprayed, laid smoothly in place over the wing
panel, and then folded back to allow the author to dope the first
section of the structure to which he wants the silkspan to adhere. It’s
usually best to begin at the wing root, as shown.
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:55 PM Page 35
36 MODEL AVIATION
Where the covering goes around a sharp curve, you can slit the
edges into a fringe. The dope will hold each little section in place
more easily.
It’s easy to use a sharp blade to trim overhang on a flat surface
such as this. Practice will teach you to make a single, clean cut
through the covering without slicing into the wood.
When a structure section such as this wingtip lies in a plane of its
own, it might be easier to cover it as a separate piece. The
silkspan has been cut to size, dampened, and set in place, with
dope only on the rib at the top. A well-trained thumb is a big help.
This is the beginning of a double overlap. Never pass up the
opportunity to use that method; leaving open balsa edges throws
away potential structural strength and makes finishing more
difficult.
See the Rest of the Build Online!
We only had room to show you step-by-step pictures of the
wing. You can see R.A. Benjamin’s techniques for covering
the fuselage and tail sections on the Model Aviation Online
site, in the Exclusive Online Features section. MA
—MA Staff
Sources:
Model Aviation Online
www.modelaircraft.org/mag
For the little 1- or 2-foot-wingspan stick-and-tissue rubberpowered
models that were built in WW II times, Japanese tissue was
the best choice. It was usually included with any kit you might be
lucky enough to get.
For models spanning 3-4 feet or more, the extra strength that
silkspan provided made it a better choice than Japanese tissue. Real
silk was best for huge models, especially FF or CL gas-powered
aircraft, but it cost four to five times as much as silkspan and
demanded that you use more dope to seal it and build a good finish.
In the mid-1950s, when I became aware of silkspan, a 2 x 3-foot
sheet cost 15¢-25¢ at a hobby shop, depending on the weight
grade/thickness you wanted. It was good stuff.
From the end of the war through the 1960s, almost any mediumsize
model kit you could find had one or more sheets of silkspan
tucked in with the various sheets of balsa or rolled up with the plans.
You couldn’t call yourself a model builder if you couldn’t use
silkspan.
It’s still good, but these days hobby shops (both walk-in and mail
order) offer an impressive range of iron-on products that are
designed to seal balsa surfaces, cover “open” structures such as
wings, and put a color finish on your aircraft at once.
There’s no shortage of well-meaning experts who will assure you
that products such as silkspan are too hard to bother with anymore.
And it’s no surprise that good ol’ plain silkspan can get lost in the
glitter of all those guaranteed-to-be-shiny colors.
These one-step covering materials fall into several categories
Photos by the author
05sig2.QXD_00MSTRPG.QXD 3/23/11 11:30 AM Page 36
May 2011 37
Fold the loose covering back, and dope the remaining
edges.
You can trim the silkspan along the back side of a curved surface,
such as a wingtip, using a sharp blade and a delicate touch. Don’t
cut the wood!
This is the back side (top surface) of the wingtip. Get plenty of
fresh dope on the places where the silkspan is going to stick.
including Mylar film, polyester film, and synthetic fabric, and all
of them transform a series of tasks—that had to be completed
before you could fly your model—into one operation.
What’s wrong with that? Maybe nothing, depending on what
you want.
All iron-on coverings are quick to apply, relatively light, and
strong enough to stand up to plenty of real-world use. But all are
susceptible to sagging, wrinkling, and seam slippage in time.
It’s almost impossible to hide the seams and just about as
hard to get paint of any kind to stick reliably to iron-on covering.
There is no good way to cover concave surfaces such as wingroot
fillets with the material, and no matter what you do it looks
like exactly what it is: high-tech plastic wrap.
It’s similar to comparing a durable formed-plastic table and a
hand-crafted hardwood desktop. Both do their intended jobs
well, but each conveys a different message.
If I have your interest, read on. I will take you through an
introductory course in learning the secrets of silkspan. I am
presenting the lesson as a photo essay.
I’m using a real vintage design as the subject. During the late 1940s
What Is Dope?
It’s a paint product, similar to lacquer, that for a long
time was the only practical sealer and finish base for fabriccovered
full-scale and model airplanes. Many alternatives
have appeared on the market in recent years, but there are
still some things that dope does best, one of which is to use
with various paper-based materials to cover model aircraft.
As far as we are concerned, there are two kinds of dope:
cellulose acetate butyrate and cellulose nitrate. “Butyrate”
is the kind aeromodelers have used for decades, because it
is fuelproof (resistant to the alcohol in glow engine fuel).
“Nitrate” dope was around first, but it fell out of favor in
aeromodeling because glow fuel turns it into a gooey mess.
The problem is that butyrate doesn’t dry as soon as you
might think, and delayed shrinkage can distort model
structures months after finishing.
Moreover, nothing much sticks well to butyrate dope
except more butyrate dope, which limits your options.
Nitrate dope appears to dry after several hours or fewer,
and it really does. A nitrate dope base is stable and won’t
sneak up later and warp your wings.
You can also use nontautening nitrate dope, which
won’t shrink a covering any tighter than it was when you
put it on the structure.
Almost any other kind of paint product you can think of
sticks to nitrate dope. You can finish over it with more
nitrate, butyrate, enamel, epoxy, acrylic, or whatever else
you might want to experiment with.
If you are using electric power, the fuel issue goes away.
It’s good to remember, though, that the truly fuelproof
finishes, such as epoxy and urethanes, stick to a nitrate dope
base way better than they do to butyrate. MA
—R.A. Benjamin
05sig2.QXD_00MSTRPG.QXD 3/22/11 1:01 PM Page 37
and all through the 1950s, the 54-inch-span
Comet Aeronca Chief was available as a
classic rubber-powered FF stick-and-tissue
printwood kit.
“Printwood” meant that all parts, such as
wing ribs and fuselage formers, were cut to a
pattern printed in black ink on sheets of the
requisite thickness of balsa. You cut out each
part in turn with a razor blade or one of those
pointy model knives, if you could afford it
back then. Whether the parts would fit or not
was up to you.
If you can find an original printwood kit
today, you will probably have to pay a
collector price for it. I used a replica laser-cut
short kit with an exact copy of the old plans
from Tom Martin Radio Control.
I did extensive modifications to turn the
Chief into an electric-powered RC model. I
added ailerons, spars, fuselage stringers, and
scale dihedral, along with many details, but
my Comet Aeronca is still a nearly perfect
example of the art of covering with silkspan.
We are ready to cover the airplane, but
there are a few things that need to be checked
one more time before we begin cutting those
nice white sheets of silkspan into workingsized
pieces.
All structural work must be complete. All
power and control-system components must
be in place and tested. You can remove some
or all of the equipment while covering and
doping, but after you have done a beautiful
38 MODEL AVIATION
For further information, details, and pricing, contact
Zurich International, 9418 Snow Lake Place, Elk Grove, CA 95758
www.extremeglaresunglasses.com • [email protected] • 1-800-533-5665 • 916-691-6467
International Place Grove
See Better, Fly Better
with No Sun Glare!
The Best Sun & U.V. Protection
in the World!
Available in “fi t over style”
and Fashion “Pilot” Style.
“Extreme Glare” Technology
now made in Prescription
Lenses with outstanding
glare protection
job of finishing the fuselage is not the time
to discover that you can’t get the elevator
pushrod supports in place without cutting a
hole in something.
Various trim bits such as air intakes,
wing fairings, etc. might be designed for
mounting after covering. You’ll know it
when that happens.
Sand everything again. Every rough
spot, glue lump, or carelessly rounded edge
will show through the finished silkspan. Get
those things right while you have the
chance.
Dope the entire structure. Get at least
one wet coat of whichever variety of clear
dope you are using onto every structural
surface you can reach. This helps seal out
moisture and will impart a bit of resiliency
to the airframe, while sealing the wood so
that the dope you use as a covering
adhesive won’t be soaked up too quickly.
Sand every bit of structure that will
come in contact with the covering with
320-grit or finer abrasive paper. This will
help prevent snagging and tearing the
silkspan as you cover. It wouldn’t hurt to
give those contacting surfaces another coat
of clear dope and another careful sanding.
Now you are ready. You will find each
step of the process illustrated in
photographs, with relevant instructions in
the captions.
Edition: Model Aviation - 2011/05
Page Numbers: 34,35,36,37,38
34 MODEL AVIATION
by R.A. Benjamin
1
A golden-oldie
covering that’ s too
good to go away
Secrets
of
Left: Tools of the trade. Along with the Comet Aeronca
C h i e f f u s e l a g e r e a dy f o r c ov e ri ng i s a b ig j a r of
n o n tau tening c lear n it r at e d o p e and brush, a water
spray bottle, a sheet of silkspan, and an aileron that the
author has already covered.
SILKSPAN IS A unique variety of tissue
paper made from carefully selected plant
fiber. It’s the stuff from which teabags are
made. At roughly the time World War II
was fought, model builders got their hands
on some of this material and discovered
that it made an excellent covering for their
airplanes.
I’m uncertain who came up with the
term “silkspan,” which is marketed under
the name Modelspan, among others. But as
the name implies, the material is closer in
durability to silk—the gold standard of
model airplane coverings—than the finergrained,
more delicate papers that
aeromodelers have always called “Japanese
tissue.”
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:48 PM Page 34
May 2011 35
Above: Fold the loose section of covering out of the way, and
dope the edges of the structure partway along the span.
Left: The damp silkspan has been laid in position, and the
author presses, pats, and gently stretches the material to get
it flat and smooth.
Left: Learning to press and pull with your thumb and
forefinger is one of the key skills to working with silkspan.
Dope, stretch, press, and pull some more, the rest of the way
out to the wingtip.
Above: The process doesn’t always work the first time. Lift
any edges that don’t stick, add more clear dope, and then
press and pull some more.
Above: The inboard end of the left wing rests on the sheet
of silkspan that has been cut to size to form the bottom
surface covering. Leave at least this amount of extra
material around the edges with which to work.
Above right: This is the top surface, but that’s okay. The sheet of
covering has been water-sprayed, laid smoothly in place over the wing
panel, and then folded back to allow the author to dope the first
section of the structure to which he wants the silkspan to adhere. It’s
usually best to begin at the wing root, as shown.
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:55 PM Page 35
36 MODEL AVIATION
Where the covering goes around a sharp curve, you can slit the
edges into a fringe. The dope will hold each little section in place
more easily.
It’s easy to use a sharp blade to trim overhang on a flat surface
such as this. Practice will teach you to make a single, clean cut
through the covering without slicing into the wood.
When a structure section such as this wingtip lies in a plane of its
own, it might be easier to cover it as a separate piece. The
silkspan has been cut to size, dampened, and set in place, with
dope only on the rib at the top. A well-trained thumb is a big help.
This is the beginning of a double overlap. Never pass up the
opportunity to use that method; leaving open balsa edges throws
away potential structural strength and makes finishing more
difficult.
See the Rest of the Build Online!
We only had room to show you step-by-step pictures of the
wing. You can see R.A. Benjamin’s techniques for covering
the fuselage and tail sections on the Model Aviation Online
site, in the Exclusive Online Features section. MA
—MA Staff
Sources:
Model Aviation Online
www.modelaircraft.org/mag
For the little 1- or 2-foot-wingspan stick-and-tissue rubberpowered
models that were built in WW II times, Japanese tissue was
the best choice. It was usually included with any kit you might be
lucky enough to get.
For models spanning 3-4 feet or more, the extra strength that
silkspan provided made it a better choice than Japanese tissue. Real
silk was best for huge models, especially FF or CL gas-powered
aircraft, but it cost four to five times as much as silkspan and
demanded that you use more dope to seal it and build a good finish.
In the mid-1950s, when I became aware of silkspan, a 2 x 3-foot
sheet cost 15¢-25¢ at a hobby shop, depending on the weight
grade/thickness you wanted. It was good stuff.
From the end of the war through the 1960s, almost any mediumsize
model kit you could find had one or more sheets of silkspan
tucked in with the various sheets of balsa or rolled up with the plans.
You couldn’t call yourself a model builder if you couldn’t use
silkspan.
It’s still good, but these days hobby shops (both walk-in and mail
order) offer an impressive range of iron-on products that are
designed to seal balsa surfaces, cover “open” structures such as
wings, and put a color finish on your aircraft at once.
There’s no shortage of well-meaning experts who will assure you
that products such as silkspan are too hard to bother with anymore.
And it’s no surprise that good ol’ plain silkspan can get lost in the
glitter of all those guaranteed-to-be-shiny colors.
These one-step covering materials fall into several categories
Photos by the author
05sig2.QXD_00MSTRPG.QXD 3/23/11 11:30 AM Page 36
May 2011 37
Fold the loose covering back, and dope the remaining
edges.
You can trim the silkspan along the back side of a curved surface,
such as a wingtip, using a sharp blade and a delicate touch. Don’t
cut the wood!
This is the back side (top surface) of the wingtip. Get plenty of
fresh dope on the places where the silkspan is going to stick.
including Mylar film, polyester film, and synthetic fabric, and all
of them transform a series of tasks—that had to be completed
before you could fly your model—into one operation.
What’s wrong with that? Maybe nothing, depending on what
you want.
All iron-on coverings are quick to apply, relatively light, and
strong enough to stand up to plenty of real-world use. But all are
susceptible to sagging, wrinkling, and seam slippage in time.
It’s almost impossible to hide the seams and just about as
hard to get paint of any kind to stick reliably to iron-on covering.
There is no good way to cover concave surfaces such as wingroot
fillets with the material, and no matter what you do it looks
like exactly what it is: high-tech plastic wrap.
It’s similar to comparing a durable formed-plastic table and a
hand-crafted hardwood desktop. Both do their intended jobs
well, but each conveys a different message.
If I have your interest, read on. I will take you through an
introductory course in learning the secrets of silkspan. I am
presenting the lesson as a photo essay.
I’m using a real vintage design as the subject. During the late 1940s
What Is Dope?
It’s a paint product, similar to lacquer, that for a long
time was the only practical sealer and finish base for fabriccovered
full-scale and model airplanes. Many alternatives
have appeared on the market in recent years, but there are
still some things that dope does best, one of which is to use
with various paper-based materials to cover model aircraft.
As far as we are concerned, there are two kinds of dope:
cellulose acetate butyrate and cellulose nitrate. “Butyrate”
is the kind aeromodelers have used for decades, because it
is fuelproof (resistant to the alcohol in glow engine fuel).
“Nitrate” dope was around first, but it fell out of favor in
aeromodeling because glow fuel turns it into a gooey mess.
The problem is that butyrate doesn’t dry as soon as you
might think, and delayed shrinkage can distort model
structures months after finishing.
Moreover, nothing much sticks well to butyrate dope
except more butyrate dope, which limits your options.
Nitrate dope appears to dry after several hours or fewer,
and it really does. A nitrate dope base is stable and won’t
sneak up later and warp your wings.
You can also use nontautening nitrate dope, which
won’t shrink a covering any tighter than it was when you
put it on the structure.
Almost any other kind of paint product you can think of
sticks to nitrate dope. You can finish over it with more
nitrate, butyrate, enamel, epoxy, acrylic, or whatever else
you might want to experiment with.
If you are using electric power, the fuel issue goes away.
It’s good to remember, though, that the truly fuelproof
finishes, such as epoxy and urethanes, stick to a nitrate dope
base way better than they do to butyrate. MA
—R.A. Benjamin
05sig2.QXD_00MSTRPG.QXD 3/22/11 1:01 PM Page 37
and all through the 1950s, the 54-inch-span
Comet Aeronca Chief was available as a
classic rubber-powered FF stick-and-tissue
printwood kit.
“Printwood” meant that all parts, such as
wing ribs and fuselage formers, were cut to a
pattern printed in black ink on sheets of the
requisite thickness of balsa. You cut out each
part in turn with a razor blade or one of those
pointy model knives, if you could afford it
back then. Whether the parts would fit or not
was up to you.
If you can find an original printwood kit
today, you will probably have to pay a
collector price for it. I used a replica laser-cut
short kit with an exact copy of the old plans
from Tom Martin Radio Control.
I did extensive modifications to turn the
Chief into an electric-powered RC model. I
added ailerons, spars, fuselage stringers, and
scale dihedral, along with many details, but
my Comet Aeronca is still a nearly perfect
example of the art of covering with silkspan.
We are ready to cover the airplane, but
there are a few things that need to be checked
one more time before we begin cutting those
nice white sheets of silkspan into workingsized
pieces.
All structural work must be complete. All
power and control-system components must
be in place and tested. You can remove some
or all of the equipment while covering and
doping, but after you have done a beautiful
38 MODEL AVIATION
For further information, details, and pricing, contact
Zurich International, 9418 Snow Lake Place, Elk Grove, CA 95758
www.extremeglaresunglasses.com • [email protected] • 1-800-533-5665 • 916-691-6467
International Place Grove
See Better, Fly Better
with No Sun Glare!
The Best Sun & U.V. Protection
in the World!
Available in “fi t over style”
and Fashion “Pilot” Style.
“Extreme Glare” Technology
now made in Prescription
Lenses with outstanding
glare protection
job of finishing the fuselage is not the time
to discover that you can’t get the elevator
pushrod supports in place without cutting a
hole in something.
Various trim bits such as air intakes,
wing fairings, etc. might be designed for
mounting after covering. You’ll know it
when that happens.
Sand everything again. Every rough
spot, glue lump, or carelessly rounded edge
will show through the finished silkspan. Get
those things right while you have the
chance.
Dope the entire structure. Get at least
one wet coat of whichever variety of clear
dope you are using onto every structural
surface you can reach. This helps seal out
moisture and will impart a bit of resiliency
to the airframe, while sealing the wood so
that the dope you use as a covering
adhesive won’t be soaked up too quickly.
Sand every bit of structure that will
come in contact with the covering with
320-grit or finer abrasive paper. This will
help prevent snagging and tearing the
silkspan as you cover. It wouldn’t hurt to
give those contacting surfaces another coat
of clear dope and another careful sanding.
Now you are ready. You will find each
step of the process illustrated in
photographs, with relevant instructions in
the captions.
Edition: Model Aviation - 2011/05
Page Numbers: 34,35,36,37,38
34 MODEL AVIATION
by R.A. Benjamin
1
A golden-oldie
covering that’ s too
good to go away
Secrets
of
Left: Tools of the trade. Along with the Comet Aeronca
C h i e f f u s e l a g e r e a dy f o r c ov e ri ng i s a b ig j a r of
n o n tau tening c lear n it r at e d o p e and brush, a water
spray bottle, a sheet of silkspan, and an aileron that the
author has already covered.
SILKSPAN IS A unique variety of tissue
paper made from carefully selected plant
fiber. It’s the stuff from which teabags are
made. At roughly the time World War II
was fought, model builders got their hands
on some of this material and discovered
that it made an excellent covering for their
airplanes.
I’m uncertain who came up with the
term “silkspan,” which is marketed under
the name Modelspan, among others. But as
the name implies, the material is closer in
durability to silk—the gold standard of
model airplane coverings—than the finergrained,
more delicate papers that
aeromodelers have always called “Japanese
tissue.”
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:48 PM Page 34
May 2011 35
Above: Fold the loose section of covering out of the way, and
dope the edges of the structure partway along the span.
Left: The damp silkspan has been laid in position, and the
author presses, pats, and gently stretches the material to get
it flat and smooth.
Left: Learning to press and pull with your thumb and
forefinger is one of the key skills to working with silkspan.
Dope, stretch, press, and pull some more, the rest of the way
out to the wingtip.
Above: The process doesn’t always work the first time. Lift
any edges that don’t stick, add more clear dope, and then
press and pull some more.
Above: The inboard end of the left wing rests on the sheet
of silkspan that has been cut to size to form the bottom
surface covering. Leave at least this amount of extra
material around the edges with which to work.
Above right: This is the top surface, but that’s okay. The sheet of
covering has been water-sprayed, laid smoothly in place over the wing
panel, and then folded back to allow the author to dope the first
section of the structure to which he wants the silkspan to adhere. It’s
usually best to begin at the wing root, as shown.
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:55 PM Page 35
36 MODEL AVIATION
Where the covering goes around a sharp curve, you can slit the
edges into a fringe. The dope will hold each little section in place
more easily.
It’s easy to use a sharp blade to trim overhang on a flat surface
such as this. Practice will teach you to make a single, clean cut
through the covering without slicing into the wood.
When a structure section such as this wingtip lies in a plane of its
own, it might be easier to cover it as a separate piece. The
silkspan has been cut to size, dampened, and set in place, with
dope only on the rib at the top. A well-trained thumb is a big help.
This is the beginning of a double overlap. Never pass up the
opportunity to use that method; leaving open balsa edges throws
away potential structural strength and makes finishing more
difficult.
See the Rest of the Build Online!
We only had room to show you step-by-step pictures of the
wing. You can see R.A. Benjamin’s techniques for covering
the fuselage and tail sections on the Model Aviation Online
site, in the Exclusive Online Features section. MA
—MA Staff
Sources:
Model Aviation Online
www.modelaircraft.org/mag
For the little 1- or 2-foot-wingspan stick-and-tissue rubberpowered
models that were built in WW II times, Japanese tissue was
the best choice. It was usually included with any kit you might be
lucky enough to get.
For models spanning 3-4 feet or more, the extra strength that
silkspan provided made it a better choice than Japanese tissue. Real
silk was best for huge models, especially FF or CL gas-powered
aircraft, but it cost four to five times as much as silkspan and
demanded that you use more dope to seal it and build a good finish.
In the mid-1950s, when I became aware of silkspan, a 2 x 3-foot
sheet cost 15¢-25¢ at a hobby shop, depending on the weight
grade/thickness you wanted. It was good stuff.
From the end of the war through the 1960s, almost any mediumsize
model kit you could find had one or more sheets of silkspan
tucked in with the various sheets of balsa or rolled up with the plans.
You couldn’t call yourself a model builder if you couldn’t use
silkspan.
It’s still good, but these days hobby shops (both walk-in and mail
order) offer an impressive range of iron-on products that are
designed to seal balsa surfaces, cover “open” structures such as
wings, and put a color finish on your aircraft at once.
There’s no shortage of well-meaning experts who will assure you
that products such as silkspan are too hard to bother with anymore.
And it’s no surprise that good ol’ plain silkspan can get lost in the
glitter of all those guaranteed-to-be-shiny colors.
These one-step covering materials fall into several categories
Photos by the author
05sig2.QXD_00MSTRPG.QXD 3/23/11 11:30 AM Page 36
May 2011 37
Fold the loose covering back, and dope the remaining
edges.
You can trim the silkspan along the back side of a curved surface,
such as a wingtip, using a sharp blade and a delicate touch. Don’t
cut the wood!
This is the back side (top surface) of the wingtip. Get plenty of
fresh dope on the places where the silkspan is going to stick.
including Mylar film, polyester film, and synthetic fabric, and all
of them transform a series of tasks—that had to be completed
before you could fly your model—into one operation.
What’s wrong with that? Maybe nothing, depending on what
you want.
All iron-on coverings are quick to apply, relatively light, and
strong enough to stand up to plenty of real-world use. But all are
susceptible to sagging, wrinkling, and seam slippage in time.
It’s almost impossible to hide the seams and just about as
hard to get paint of any kind to stick reliably to iron-on covering.
There is no good way to cover concave surfaces such as wingroot
fillets with the material, and no matter what you do it looks
like exactly what it is: high-tech plastic wrap.
It’s similar to comparing a durable formed-plastic table and a
hand-crafted hardwood desktop. Both do their intended jobs
well, but each conveys a different message.
If I have your interest, read on. I will take you through an
introductory course in learning the secrets of silkspan. I am
presenting the lesson as a photo essay.
I’m using a real vintage design as the subject. During the late 1940s
What Is Dope?
It’s a paint product, similar to lacquer, that for a long
time was the only practical sealer and finish base for fabriccovered
full-scale and model airplanes. Many alternatives
have appeared on the market in recent years, but there are
still some things that dope does best, one of which is to use
with various paper-based materials to cover model aircraft.
As far as we are concerned, there are two kinds of dope:
cellulose acetate butyrate and cellulose nitrate. “Butyrate”
is the kind aeromodelers have used for decades, because it
is fuelproof (resistant to the alcohol in glow engine fuel).
“Nitrate” dope was around first, but it fell out of favor in
aeromodeling because glow fuel turns it into a gooey mess.
The problem is that butyrate doesn’t dry as soon as you
might think, and delayed shrinkage can distort model
structures months after finishing.
Moreover, nothing much sticks well to butyrate dope
except more butyrate dope, which limits your options.
Nitrate dope appears to dry after several hours or fewer,
and it really does. A nitrate dope base is stable and won’t
sneak up later and warp your wings.
You can also use nontautening nitrate dope, which
won’t shrink a covering any tighter than it was when you
put it on the structure.
Almost any other kind of paint product you can think of
sticks to nitrate dope. You can finish over it with more
nitrate, butyrate, enamel, epoxy, acrylic, or whatever else
you might want to experiment with.
If you are using electric power, the fuel issue goes away.
It’s good to remember, though, that the truly fuelproof
finishes, such as epoxy and urethanes, stick to a nitrate dope
base way better than they do to butyrate. MA
—R.A. Benjamin
05sig2.QXD_00MSTRPG.QXD 3/22/11 1:01 PM Page 37
and all through the 1950s, the 54-inch-span
Comet Aeronca Chief was available as a
classic rubber-powered FF stick-and-tissue
printwood kit.
“Printwood” meant that all parts, such as
wing ribs and fuselage formers, were cut to a
pattern printed in black ink on sheets of the
requisite thickness of balsa. You cut out each
part in turn with a razor blade or one of those
pointy model knives, if you could afford it
back then. Whether the parts would fit or not
was up to you.
If you can find an original printwood kit
today, you will probably have to pay a
collector price for it. I used a replica laser-cut
short kit with an exact copy of the old plans
from Tom Martin Radio Control.
I did extensive modifications to turn the
Chief into an electric-powered RC model. I
added ailerons, spars, fuselage stringers, and
scale dihedral, along with many details, but
my Comet Aeronca is still a nearly perfect
example of the art of covering with silkspan.
We are ready to cover the airplane, but
there are a few things that need to be checked
one more time before we begin cutting those
nice white sheets of silkspan into workingsized
pieces.
All structural work must be complete. All
power and control-system components must
be in place and tested. You can remove some
or all of the equipment while covering and
doping, but after you have done a beautiful
38 MODEL AVIATION
For further information, details, and pricing, contact
Zurich International, 9418 Snow Lake Place, Elk Grove, CA 95758
www.extremeglaresunglasses.com • [email protected] • 1-800-533-5665 • 916-691-6467
International Place Grove
See Better, Fly Better
with No Sun Glare!
The Best Sun & U.V. Protection
in the World!
Available in “fi t over style”
and Fashion “Pilot” Style.
“Extreme Glare” Technology
now made in Prescription
Lenses with outstanding
glare protection
job of finishing the fuselage is not the time
to discover that you can’t get the elevator
pushrod supports in place without cutting a
hole in something.
Various trim bits such as air intakes,
wing fairings, etc. might be designed for
mounting after covering. You’ll know it
when that happens.
Sand everything again. Every rough
spot, glue lump, or carelessly rounded edge
will show through the finished silkspan. Get
those things right while you have the
chance.
Dope the entire structure. Get at least
one wet coat of whichever variety of clear
dope you are using onto every structural
surface you can reach. This helps seal out
moisture and will impart a bit of resiliency
to the airframe, while sealing the wood so
that the dope you use as a covering
adhesive won’t be soaked up too quickly.
Sand every bit of structure that will
come in contact with the covering with
320-grit or finer abrasive paper. This will
help prevent snagging and tearing the
silkspan as you cover. It wouldn’t hurt to
give those contacting surfaces another coat
of clear dope and another careful sanding.
Now you are ready. You will find each
step of the process illustrated in
photographs, with relevant instructions in
the captions.
Edition: Model Aviation - 2011/05
Page Numbers: 34,35,36,37,38
34 MODEL AVIATION
by R.A. Benjamin
1
A golden-oldie
covering that’ s too
good to go away
Secrets
of
Left: Tools of the trade. Along with the Comet Aeronca
C h i e f f u s e l a g e r e a dy f o r c ov e ri ng i s a b ig j a r of
n o n tau tening c lear n it r at e d o p e and brush, a water
spray bottle, a sheet of silkspan, and an aileron that the
author has already covered.
SILKSPAN IS A unique variety of tissue
paper made from carefully selected plant
fiber. It’s the stuff from which teabags are
made. At roughly the time World War II
was fought, model builders got their hands
on some of this material and discovered
that it made an excellent covering for their
airplanes.
I’m uncertain who came up with the
term “silkspan,” which is marketed under
the name Modelspan, among others. But as
the name implies, the material is closer in
durability to silk—the gold standard of
model airplane coverings—than the finergrained,
more delicate papers that
aeromodelers have always called “Japanese
tissue.”
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:48 PM Page 34
May 2011 35
Above: Fold the loose section of covering out of the way, and
dope the edges of the structure partway along the span.
Left: The damp silkspan has been laid in position, and the
author presses, pats, and gently stretches the material to get
it flat and smooth.
Left: Learning to press and pull with your thumb and
forefinger is one of the key skills to working with silkspan.
Dope, stretch, press, and pull some more, the rest of the way
out to the wingtip.
Above: The process doesn’t always work the first time. Lift
any edges that don’t stick, add more clear dope, and then
press and pull some more.
Above: The inboard end of the left wing rests on the sheet
of silkspan that has been cut to size to form the bottom
surface covering. Leave at least this amount of extra
material around the edges with which to work.
Above right: This is the top surface, but that’s okay. The sheet of
covering has been water-sprayed, laid smoothly in place over the wing
panel, and then folded back to allow the author to dope the first
section of the structure to which he wants the silkspan to adhere. It’s
usually best to begin at the wing root, as shown.
05sig2.QXD_00MSTRPG.QXD 3/22/11 12:55 PM Page 35
36 MODEL AVIATION
Where the covering goes around a sharp curve, you can slit the
edges into a fringe. The dope will hold each little section in place
more easily.
It’s easy to use a sharp blade to trim overhang on a flat surface
such as this. Practice will teach you to make a single, clean cut
through the covering without slicing into the wood.
When a structure section such as this wingtip lies in a plane of its
own, it might be easier to cover it as a separate piece. The
silkspan has been cut to size, dampened, and set in place, with
dope only on the rib at the top. A well-trained thumb is a big help.
This is the beginning of a double overlap. Never pass up the
opportunity to use that method; leaving open balsa edges throws
away potential structural strength and makes finishing more
difficult.
See the Rest of the Build Online!
We only had room to show you step-by-step pictures of the
wing. You can see R.A. Benjamin’s techniques for covering
the fuselage and tail sections on the Model Aviation Online
site, in the Exclusive Online Features section. MA
—MA Staff
Sources:
Model Aviation Online
www.modelaircraft.org/mag
For the little 1- or 2-foot-wingspan stick-and-tissue rubberpowered
models that were built in WW II times, Japanese tissue was
the best choice. It was usually included with any kit you might be
lucky enough to get.
For models spanning 3-4 feet or more, the extra strength that
silkspan provided made it a better choice than Japanese tissue. Real
silk was best for huge models, especially FF or CL gas-powered
aircraft, but it cost four to five times as much as silkspan and
demanded that you use more dope to seal it and build a good finish.
In the mid-1950s, when I became aware of silkspan, a 2 x 3-foot
sheet cost 15¢-25¢ at a hobby shop, depending on the weight
grade/thickness you wanted. It was good stuff.
From the end of the war through the 1960s, almost any mediumsize
model kit you could find had one or more sheets of silkspan
tucked in with the various sheets of balsa or rolled up with the plans.
You couldn’t call yourself a model builder if you couldn’t use
silkspan.
It’s still good, but these days hobby shops (both walk-in and mail
order) offer an impressive range of iron-on products that are
designed to seal balsa surfaces, cover “open” structures such as
wings, and put a color finish on your aircraft at once.
There’s no shortage of well-meaning experts who will assure you
that products such as silkspan are too hard to bother with anymore.
And it’s no surprise that good ol’ plain silkspan can get lost in the
glitter of all those guaranteed-to-be-shiny colors.
These one-step covering materials fall into several categories
Photos by the author
05sig2.QXD_00MSTRPG.QXD 3/23/11 11:30 AM Page 36
May 2011 37
Fold the loose covering back, and dope the remaining
edges.
You can trim the silkspan along the back side of a curved surface,
such as a wingtip, using a sharp blade and a delicate touch. Don’t
cut the wood!
This is the back side (top surface) of the wingtip. Get plenty of
fresh dope on the places where the silkspan is going to stick.
including Mylar film, polyester film, and synthetic fabric, and all
of them transform a series of tasks—that had to be completed
before you could fly your model—into one operation.
What’s wrong with that? Maybe nothing, depending on what
you want.
All iron-on coverings are quick to apply, relatively light, and
strong enough to stand up to plenty of real-world use. But all are
susceptible to sagging, wrinkling, and seam slippage in time.
It’s almost impossible to hide the seams and just about as
hard to get paint of any kind to stick reliably to iron-on covering.
There is no good way to cover concave surfaces such as wingroot
fillets with the material, and no matter what you do it looks
like exactly what it is: high-tech plastic wrap.
It’s similar to comparing a durable formed-plastic table and a
hand-crafted hardwood desktop. Both do their intended jobs
well, but each conveys a different message.
If I have your interest, read on. I will take you through an
introductory course in learning the secrets of silkspan. I am
presenting the lesson as a photo essay.
I’m using a real vintage design as the subject. During the late 1940s
What Is Dope?
It’s a paint product, similar to lacquer, that for a long
time was the only practical sealer and finish base for fabriccovered
full-scale and model airplanes. Many alternatives
have appeared on the market in recent years, but there are
still some things that dope does best, one of which is to use
with various paper-based materials to cover model aircraft.
As far as we are concerned, there are two kinds of dope:
cellulose acetate butyrate and cellulose nitrate. “Butyrate”
is the kind aeromodelers have used for decades, because it
is fuelproof (resistant to the alcohol in glow engine fuel).
“Nitrate” dope was around first, but it fell out of favor in
aeromodeling because glow fuel turns it into a gooey mess.
The problem is that butyrate doesn’t dry as soon as you
might think, and delayed shrinkage can distort model
structures months after finishing.
Moreover, nothing much sticks well to butyrate dope
except more butyrate dope, which limits your options.
Nitrate dope appears to dry after several hours or fewer,
and it really does. A nitrate dope base is stable and won’t
sneak up later and warp your wings.
You can also use nontautening nitrate dope, which
won’t shrink a covering any tighter than it was when you
put it on the structure.
Almost any other kind of paint product you can think of
sticks to nitrate dope. You can finish over it with more
nitrate, butyrate, enamel, epoxy, acrylic, or whatever else
you might want to experiment with.
If you are using electric power, the fuel issue goes away.
It’s good to remember, though, that the truly fuelproof
finishes, such as epoxy and urethanes, stick to a nitrate dope
base way better than they do to butyrate. MA
—R.A. Benjamin
05sig2.QXD_00MSTRPG.QXD 3/22/11 1:01 PM Page 37
and all through the 1950s, the 54-inch-span
Comet Aeronca Chief was available as a
classic rubber-powered FF stick-and-tissue
printwood kit.
“Printwood” meant that all parts, such as
wing ribs and fuselage formers, were cut to a
pattern printed in black ink on sheets of the
requisite thickness of balsa. You cut out each
part in turn with a razor blade or one of those
pointy model knives, if you could afford it
back then. Whether the parts would fit or not
was up to you.
If you can find an original printwood kit
today, you will probably have to pay a
collector price for it. I used a replica laser-cut
short kit with an exact copy of the old plans
from Tom Martin Radio Control.
I did extensive modifications to turn the
Chief into an electric-powered RC model. I
added ailerons, spars, fuselage stringers, and
scale dihedral, along with many details, but
my Comet Aeronca is still a nearly perfect
example of the art of covering with silkspan.
We are ready to cover the airplane, but
there are a few things that need to be checked
one more time before we begin cutting those
nice white sheets of silkspan into workingsized
pieces.
All structural work must be complete. All
power and control-system components must
be in place and tested. You can remove some
or all of the equipment while covering and
doping, but after you have done a beautiful
38 MODEL AVIATION
For further information, details, and pricing, contact
Zurich International, 9418 Snow Lake Place, Elk Grove, CA 95758
www.extremeglaresunglasses.com • [email protected] • 1-800-533-5665 • 916-691-6467
International Place Grove
See Better, Fly Better
with No Sun Glare!
The Best Sun & U.V. Protection
in the World!
Available in “fi t over style”
and Fashion “Pilot” Style.
“Extreme Glare” Technology
now made in Prescription
Lenses with outstanding
glare protection
job of finishing the fuselage is not the time
to discover that you can’t get the elevator
pushrod supports in place without cutting a
hole in something.
Various trim bits such as air intakes,
wing fairings, etc. might be designed for
mounting after covering. You’ll know it
when that happens.
Sand everything again. Every rough
spot, glue lump, or carelessly rounded edge
will show through the finished silkspan. Get
those things right while you have the
chance.
Dope the entire structure. Get at least
one wet coat of whichever variety of clear
dope you are using onto every structural
surface you can reach. This helps seal out
moisture and will impart a bit of resiliency
to the airframe, while sealing the wood so
that the dope you use as a covering
adhesive won’t be soaked up too quickly.
Sand every bit of structure that will
come in contact with the covering with
320-grit or finer abrasive paper. This will
help prevent snagging and tearing the
silkspan as you cover. It wouldn’t hurt to
give those contacting surfaces another coat
of clear dope and another careful sanding.
Now you are ready. You will find each
step of the process illustrated in
photographs, with relevant instructions in
the captions.
