ARF PATCHING
TECHNIQUES by
Steve Hunt
No matter what causes the damage, whether it's a rock or your
son's model car, a repair occasionally needs to be made!
These are the tools and materials that are required to make a
seamless repair in an ARF aircraft's wing.
SOMETIMES WE DON’T get quite the landing we had hoped
for or a pet rock takes a “shortcut” through our model’s wing.
Sometimes we just have to admit that we dropped something
onto—and on through—the wing.
This article is primarily for new pilots or those who have flown
only the ARF versions of airplanes. However, even seasoned
modelers might find a method here that is useful for repairing all
fixed-wing models incorporating boxed-in (ribbed and sheeted)
areas.
Please reacquaint yourself with the safety and
recommendations of the particular brand of modeling knife and
adhesives you will be using. The knife can cut you with very little
force, to the extent that you will need stitches. To make sure you
don’t need stitches for another reason, make sure you have a
proper cutting board under your work when you use the modeling
knife.
The cyanoacrylate glue can stick your fingers together or to
another object in seconds. When you are holding parts in place
while this glue is curing, use some plastic backing from your
covering; it was engineered so that adhesives will not stick to it.
Procedure: Cut back as much covering as necessary to examine
and repair without the remainder of the covering being in the way.
Remove the broken pieces of the model, and square off the
damaged area using the modeling knife.
Dealing with oddly shaped damaged areas is common, but try
to keep the replacement area as small as possible. Once the
harmed sheeting is cut away, inspect for hidden damage such as a
broken spar or crushed ribs.
Broken ribs are fairly easy to repair by manufacturing one of
like contour and gluing it onto the side of the original. If you
encounter a broken main spar, seek some advice from a more
Tools and Items Needed for Patching
• Sharp modeling-knife handle fitted with #11 blade.
• Pounce wheel.
• Holding tool made from music wire.
• Replacement balsa that is the same thickness as the
sheeting on the wing.
• Thin scrap balsa.
• Sanding block.
• T-pins.
• Cyanoacrylate glue.
• Yellow wood glue.
• Aluminum foil.
Photos courtesy the author
Remove as much of the surrounding covering material as
necessary to make the repair. It's better to remove a bit too much
than not enough.
Use the modeling knife to square off the opening as best you
can. Try to keep the edges of the opening straight.
Cut several cross-grain reinforcement strips to use under the lip
of the sheeting in the prepared area.
experienced builder. Spars are load-carrying members, and their
integrity must be maintained for safety’s sake.
Make reinforcement strips, which are cut cross-grain from
scrap balsa. Install these in place on the underside of the existing
sheeting in the damaged area using cyanoacrylate glue. Hold the
reinforcement strips in place using the custom-made holding tool,
which is shown, until the cyanoacrylate cures.
If the area to be repaired is too close to a rib, spar, or other
support, make a ledge using 1⁄4 balsa fit to contour and glue it in
place, leaving room for the replacement balsa to fit flush when
installed. Now the damaged area is prepared for new sheeting.
Place a piece of aluminum foil over the prepared hole. While
holding the foil so it does not move, trace the edges of the hole
with your finger and make a visible crease at all edges.
Carefully place and hold the aluminum foil over the replacement
balsa stock, being careful not to smooth out any of the creases.
(To hold it, you can press two fingers on the foil inside the traced
area or use tape on the outer edges and/or T-pins placed out of the
way of the pounce wheel.)
A pounce wheel is a small, spurlike tool that is used to transfer
patterns to wood. While holding the aluminum foil firmly in
place, run this tool along the edge of each traced mark. If you are
unable to locate a pounce wheel, you can make a series of pin
pricks along the creases. It produces the same effect but takes
longer.
Remove the foil from the balsa, and then cut along the dotted
lines left in the wood. Make the cross-grain cuts first. Use light
pressure on the knife blade for these cross-grain slices, and make
several passes with the knife until it cuts cleanly through the
balsa. If you try to make the cross-grain cuts with one knife pass,
the result might be a split part.
Carefully sand the edges of this replacement part until it fits
perfectly inside the prepared area. Sandpaper cuts quickly, so
check your progress after one or two passes to make sure that you
are not removing too much material.
If the damaged section is in a curved portion of the wing, such
as the LE area, you may need to bend the replacement panel
slightly to fit by lightly dampening the panel with water on the
outside before gluing. To do that, dip your fingers in water and
shake off the excess, and then lightly rub the outside surface of
the insert. Don’t saturate the wood; wet balsa warps and does not
glue well.
Install the replacement part using a yellow wood glue (such as
an aliphatic type) and remove any excess glue using a damp paper
towel. You can use small weights to hold the replacement part in
place on curved areas. Use plastic sheeting to keep the glue from
sticking to your weights while it sets.
You should allow the adhesive to dry for several hours before
sanding. You can use five-minute epoxy here, but it is more
difficult to sand smooth. The more time and care you take in
preparation, the better the fit will be.
After the glue has dried and the surface has been sanded to
your satisfaction, there may still be some small gaps in the seam
between the wing and the patch. You can fill these with a vinyl
spackling compound. When the spackling is dry, it is simple to
block-sand even with the surface.
At this point you can re-cover the repaired area with a heatshrink
film that closely matches the original finish.
Additional Thoughts: The custom holding tool shown was made
from some small-diameter music wire. It was bent in such a
manner that it allowed the tool to splice pieces in place under the
sheeting while the glue cured.
I have only been successful in locating pounce wheels at
Micro-Mark; they are $19.95 for a set of three (item 15200). Visit
the company online at www.micromark.com. MA
Steven Hunt
Box 1152
Evansville WY 82636
[email protected]
Repair any internal damage to ribs before proceeding. The hole
is shown ready for the patch.
Install the reinforcement strips using the custom wire tool and
cyanoacrylate glue. They form a sort of "shelf."
Place aluminum foil over the replacement balsa stock—being
careful not to smooth any of the creases—then run the pounce
wheel around the creased edge.
Place a piece of aluminum foil over the prepared hole. Trace
the edges of the hole with your finger, making a visible crease
at all edges.
With the aluminum foil removed, you can easily see the marked
area that will become the patch piece.
Carefully cut the patch along the outside of the marked lines
with the modeling knife. Leave some material to allow a perfect
fit with some sanding.
Sand and test-fit the patch until it fits the prepared hole
seamlessly. Take your time; a perfect fit will yield a stronger joint.
Re-cover the wing in the repaired area using a matching color
of heat-shrink film.
A closer look at the pounce wheel and custom-made wire tools
for holding the balsa reinforcement pieces in place.
Use filler or multiple thin coats of epoxy to fill voids on the
patch perimeter. Sand the area perfectly smooth.
Edition: Model Aviation - 2005/05
Page Numbers: 46,47,48,49
Edition: Model Aviation - 2005/05
Page Numbers: 46,47,48,49
ARF PATCHING
TECHNIQUES by
Steve Hunt
No matter what causes the damage, whether it's a rock or your
son's model car, a repair occasionally needs to be made!
These are the tools and materials that are required to make a
seamless repair in an ARF aircraft's wing.
SOMETIMES WE DON’T get quite the landing we had hoped
for or a pet rock takes a “shortcut” through our model’s wing.
Sometimes we just have to admit that we dropped something
onto—and on through—the wing.
This article is primarily for new pilots or those who have flown
only the ARF versions of airplanes. However, even seasoned
modelers might find a method here that is useful for repairing all
fixed-wing models incorporating boxed-in (ribbed and sheeted)
areas.
Please reacquaint yourself with the safety and
recommendations of the particular brand of modeling knife and
adhesives you will be using. The knife can cut you with very little
force, to the extent that you will need stitches. To make sure you
don’t need stitches for another reason, make sure you have a
proper cutting board under your work when you use the modeling
knife.
The cyanoacrylate glue can stick your fingers together or to
another object in seconds. When you are holding parts in place
while this glue is curing, use some plastic backing from your
covering; it was engineered so that adhesives will not stick to it.
Procedure: Cut back as much covering as necessary to examine
and repair without the remainder of the covering being in the way.
Remove the broken pieces of the model, and square off the
damaged area using the modeling knife.
Dealing with oddly shaped damaged areas is common, but try
to keep the replacement area as small as possible. Once the
harmed sheeting is cut away, inspect for hidden damage such as a
broken spar or crushed ribs.
Broken ribs are fairly easy to repair by manufacturing one of
like contour and gluing it onto the side of the original. If you
encounter a broken main spar, seek some advice from a more
Tools and Items Needed for Patching
• Sharp modeling-knife handle fitted with #11 blade.
• Pounce wheel.
• Holding tool made from music wire.
• Replacement balsa that is the same thickness as the
sheeting on the wing.
• Thin scrap balsa.
• Sanding block.
• T-pins.
• Cyanoacrylate glue.
• Yellow wood glue.
• Aluminum foil.
Photos courtesy the author
Remove as much of the surrounding covering material as
necessary to make the repair. It's better to remove a bit too much
than not enough.
Use the modeling knife to square off the opening as best you
can. Try to keep the edges of the opening straight.
Cut several cross-grain reinforcement strips to use under the lip
of the sheeting in the prepared area.
experienced builder. Spars are load-carrying members, and their
integrity must be maintained for safety’s sake.
Make reinforcement strips, which are cut cross-grain from
scrap balsa. Install these in place on the underside of the existing
sheeting in the damaged area using cyanoacrylate glue. Hold the
reinforcement strips in place using the custom-made holding tool,
which is shown, until the cyanoacrylate cures.
If the area to be repaired is too close to a rib, spar, or other
support, make a ledge using 1⁄4 balsa fit to contour and glue it in
place, leaving room for the replacement balsa to fit flush when
installed. Now the damaged area is prepared for new sheeting.
Place a piece of aluminum foil over the prepared hole. While
holding the foil so it does not move, trace the edges of the hole
with your finger and make a visible crease at all edges.
Carefully place and hold the aluminum foil over the replacement
balsa stock, being careful not to smooth out any of the creases.
(To hold it, you can press two fingers on the foil inside the traced
area or use tape on the outer edges and/or T-pins placed out of the
way of the pounce wheel.)
A pounce wheel is a small, spurlike tool that is used to transfer
patterns to wood. While holding the aluminum foil firmly in
place, run this tool along the edge of each traced mark. If you are
unable to locate a pounce wheel, you can make a series of pin
pricks along the creases. It produces the same effect but takes
longer.
Remove the foil from the balsa, and then cut along the dotted
lines left in the wood. Make the cross-grain cuts first. Use light
pressure on the knife blade for these cross-grain slices, and make
several passes with the knife until it cuts cleanly through the
balsa. If you try to make the cross-grain cuts with one knife pass,
the result might be a split part.
Carefully sand the edges of this replacement part until it fits
perfectly inside the prepared area. Sandpaper cuts quickly, so
check your progress after one or two passes to make sure that you
are not removing too much material.
If the damaged section is in a curved portion of the wing, such
as the LE area, you may need to bend the replacement panel
slightly to fit by lightly dampening the panel with water on the
outside before gluing. To do that, dip your fingers in water and
shake off the excess, and then lightly rub the outside surface of
the insert. Don’t saturate the wood; wet balsa warps and does not
glue well.
Install the replacement part using a yellow wood glue (such as
an aliphatic type) and remove any excess glue using a damp paper
towel. You can use small weights to hold the replacement part in
place on curved areas. Use plastic sheeting to keep the glue from
sticking to your weights while it sets.
You should allow the adhesive to dry for several hours before
sanding. You can use five-minute epoxy here, but it is more
difficult to sand smooth. The more time and care you take in
preparation, the better the fit will be.
After the glue has dried and the surface has been sanded to
your satisfaction, there may still be some small gaps in the seam
between the wing and the patch. You can fill these with a vinyl
spackling compound. When the spackling is dry, it is simple to
block-sand even with the surface.
At this point you can re-cover the repaired area with a heatshrink
film that closely matches the original finish.
Additional Thoughts: The custom holding tool shown was made
from some small-diameter music wire. It was bent in such a
manner that it allowed the tool to splice pieces in place under the
sheeting while the glue cured.
I have only been successful in locating pounce wheels at
Micro-Mark; they are $19.95 for a set of three (item 15200). Visit
the company online at www.micromark.com. MA
Steven Hunt
Box 1152
Evansville WY 82636
[email protected]
Repair any internal damage to ribs before proceeding. The hole
is shown ready for the patch.
Install the reinforcement strips using the custom wire tool and
cyanoacrylate glue. They form a sort of "shelf."
Place aluminum foil over the replacement balsa stock—being
careful not to smooth any of the creases—then run the pounce
wheel around the creased edge.
Place a piece of aluminum foil over the prepared hole. Trace
the edges of the hole with your finger, making a visible crease
at all edges.
With the aluminum foil removed, you can easily see the marked
area that will become the patch piece.
Carefully cut the patch along the outside of the marked lines
with the modeling knife. Leave some material to allow a perfect
fit with some sanding.
Sand and test-fit the patch until it fits the prepared hole
seamlessly. Take your time; a perfect fit will yield a stronger joint.
Re-cover the wing in the repaired area using a matching color
of heat-shrink film.
A closer look at the pounce wheel and custom-made wire tools
for holding the balsa reinforcement pieces in place.
Use filler or multiple thin coats of epoxy to fill voids on the
patch perimeter. Sand the area perfectly smooth.
Edition: Model Aviation - 2005/05
Page Numbers: 46,47,48,49
ARF PATCHING
TECHNIQUES by
Steve Hunt
No matter what causes the damage, whether it's a rock or your
son's model car, a repair occasionally needs to be made!
These are the tools and materials that are required to make a
seamless repair in an ARF aircraft's wing.
SOMETIMES WE DON’T get quite the landing we had hoped
for or a pet rock takes a “shortcut” through our model’s wing.
Sometimes we just have to admit that we dropped something
onto—and on through—the wing.
This article is primarily for new pilots or those who have flown
only the ARF versions of airplanes. However, even seasoned
modelers might find a method here that is useful for repairing all
fixed-wing models incorporating boxed-in (ribbed and sheeted)
areas.
Please reacquaint yourself with the safety and
recommendations of the particular brand of modeling knife and
adhesives you will be using. The knife can cut you with very little
force, to the extent that you will need stitches. To make sure you
don’t need stitches for another reason, make sure you have a
proper cutting board under your work when you use the modeling
knife.
The cyanoacrylate glue can stick your fingers together or to
another object in seconds. When you are holding parts in place
while this glue is curing, use some plastic backing from your
covering; it was engineered so that adhesives will not stick to it.
Procedure: Cut back as much covering as necessary to examine
and repair without the remainder of the covering being in the way.
Remove the broken pieces of the model, and square off the
damaged area using the modeling knife.
Dealing with oddly shaped damaged areas is common, but try
to keep the replacement area as small as possible. Once the
harmed sheeting is cut away, inspect for hidden damage such as a
broken spar or crushed ribs.
Broken ribs are fairly easy to repair by manufacturing one of
like contour and gluing it onto the side of the original. If you
encounter a broken main spar, seek some advice from a more
Tools and Items Needed for Patching
• Sharp modeling-knife handle fitted with #11 blade.
• Pounce wheel.
• Holding tool made from music wire.
• Replacement balsa that is the same thickness as the
sheeting on the wing.
• Thin scrap balsa.
• Sanding block.
• T-pins.
• Cyanoacrylate glue.
• Yellow wood glue.
• Aluminum foil.
Photos courtesy the author
Remove as much of the surrounding covering material as
necessary to make the repair. It's better to remove a bit too much
than not enough.
Use the modeling knife to square off the opening as best you
can. Try to keep the edges of the opening straight.
Cut several cross-grain reinforcement strips to use under the lip
of the sheeting in the prepared area.
experienced builder. Spars are load-carrying members, and their
integrity must be maintained for safety’s sake.
Make reinforcement strips, which are cut cross-grain from
scrap balsa. Install these in place on the underside of the existing
sheeting in the damaged area using cyanoacrylate glue. Hold the
reinforcement strips in place using the custom-made holding tool,
which is shown, until the cyanoacrylate cures.
If the area to be repaired is too close to a rib, spar, or other
support, make a ledge using 1⁄4 balsa fit to contour and glue it in
place, leaving room for the replacement balsa to fit flush when
installed. Now the damaged area is prepared for new sheeting.
Place a piece of aluminum foil over the prepared hole. While
holding the foil so it does not move, trace the edges of the hole
with your finger and make a visible crease at all edges.
Carefully place and hold the aluminum foil over the replacement
balsa stock, being careful not to smooth out any of the creases.
(To hold it, you can press two fingers on the foil inside the traced
area or use tape on the outer edges and/or T-pins placed out of the
way of the pounce wheel.)
A pounce wheel is a small, spurlike tool that is used to transfer
patterns to wood. While holding the aluminum foil firmly in
place, run this tool along the edge of each traced mark. If you are
unable to locate a pounce wheel, you can make a series of pin
pricks along the creases. It produces the same effect but takes
longer.
Remove the foil from the balsa, and then cut along the dotted
lines left in the wood. Make the cross-grain cuts first. Use light
pressure on the knife blade for these cross-grain slices, and make
several passes with the knife until it cuts cleanly through the
balsa. If you try to make the cross-grain cuts with one knife pass,
the result might be a split part.
Carefully sand the edges of this replacement part until it fits
perfectly inside the prepared area. Sandpaper cuts quickly, so
check your progress after one or two passes to make sure that you
are not removing too much material.
If the damaged section is in a curved portion of the wing, such
as the LE area, you may need to bend the replacement panel
slightly to fit by lightly dampening the panel with water on the
outside before gluing. To do that, dip your fingers in water and
shake off the excess, and then lightly rub the outside surface of
the insert. Don’t saturate the wood; wet balsa warps and does not
glue well.
Install the replacement part using a yellow wood glue (such as
an aliphatic type) and remove any excess glue using a damp paper
towel. You can use small weights to hold the replacement part in
place on curved areas. Use plastic sheeting to keep the glue from
sticking to your weights while it sets.
You should allow the adhesive to dry for several hours before
sanding. You can use five-minute epoxy here, but it is more
difficult to sand smooth. The more time and care you take in
preparation, the better the fit will be.
After the glue has dried and the surface has been sanded to
your satisfaction, there may still be some small gaps in the seam
between the wing and the patch. You can fill these with a vinyl
spackling compound. When the spackling is dry, it is simple to
block-sand even with the surface.
At this point you can re-cover the repaired area with a heatshrink
film that closely matches the original finish.
Additional Thoughts: The custom holding tool shown was made
from some small-diameter music wire. It was bent in such a
manner that it allowed the tool to splice pieces in place under the
sheeting while the glue cured.
I have only been successful in locating pounce wheels at
Micro-Mark; they are $19.95 for a set of three (item 15200). Visit
the company online at www.micromark.com. MA
Steven Hunt
Box 1152
Evansville WY 82636
[email protected]
Repair any internal damage to ribs before proceeding. The hole
is shown ready for the patch.
Install the reinforcement strips using the custom wire tool and
cyanoacrylate glue. They form a sort of "shelf."
Place aluminum foil over the replacement balsa stock—being
careful not to smooth any of the creases—then run the pounce
wheel around the creased edge.
Place a piece of aluminum foil over the prepared hole. Trace
the edges of the hole with your finger, making a visible crease
at all edges.
With the aluminum foil removed, you can easily see the marked
area that will become the patch piece.
Carefully cut the patch along the outside of the marked lines
with the modeling knife. Leave some material to allow a perfect
fit with some sanding.
Sand and test-fit the patch until it fits the prepared hole
seamlessly. Take your time; a perfect fit will yield a stronger joint.
Re-cover the wing in the repaired area using a matching color
of heat-shrink film.
A closer look at the pounce wheel and custom-made wire tools
for holding the balsa reinforcement pieces in place.
Use filler or multiple thin coats of epoxy to fill voids on the
patch perimeter. Sand the area perfectly smooth.
Edition: Model Aviation - 2005/05
Page Numbers: 46,47,48,49
ARF PATCHING
TECHNIQUES by
Steve Hunt
No matter what causes the damage, whether it's a rock or your
son's model car, a repair occasionally needs to be made!
These are the tools and materials that are required to make a
seamless repair in an ARF aircraft's wing.
SOMETIMES WE DON’T get quite the landing we had hoped
for or a pet rock takes a “shortcut” through our model’s wing.
Sometimes we just have to admit that we dropped something
onto—and on through—the wing.
This article is primarily for new pilots or those who have flown
only the ARF versions of airplanes. However, even seasoned
modelers might find a method here that is useful for repairing all
fixed-wing models incorporating boxed-in (ribbed and sheeted)
areas.
Please reacquaint yourself with the safety and
recommendations of the particular brand of modeling knife and
adhesives you will be using. The knife can cut you with very little
force, to the extent that you will need stitches. To make sure you
don’t need stitches for another reason, make sure you have a
proper cutting board under your work when you use the modeling
knife.
The cyanoacrylate glue can stick your fingers together or to
another object in seconds. When you are holding parts in place
while this glue is curing, use some plastic backing from your
covering; it was engineered so that adhesives will not stick to it.
Procedure: Cut back as much covering as necessary to examine
and repair without the remainder of the covering being in the way.
Remove the broken pieces of the model, and square off the
damaged area using the modeling knife.
Dealing with oddly shaped damaged areas is common, but try
to keep the replacement area as small as possible. Once the
harmed sheeting is cut away, inspect for hidden damage such as a
broken spar or crushed ribs.
Broken ribs are fairly easy to repair by manufacturing one of
like contour and gluing it onto the side of the original. If you
encounter a broken main spar, seek some advice from a more
Tools and Items Needed for Patching
• Sharp modeling-knife handle fitted with #11 blade.
• Pounce wheel.
• Holding tool made from music wire.
• Replacement balsa that is the same thickness as the
sheeting on the wing.
• Thin scrap balsa.
• Sanding block.
• T-pins.
• Cyanoacrylate glue.
• Yellow wood glue.
• Aluminum foil.
Photos courtesy the author
Remove as much of the surrounding covering material as
necessary to make the repair. It's better to remove a bit too much
than not enough.
Use the modeling knife to square off the opening as best you
can. Try to keep the edges of the opening straight.
Cut several cross-grain reinforcement strips to use under the lip
of the sheeting in the prepared area.
experienced builder. Spars are load-carrying members, and their
integrity must be maintained for safety’s sake.
Make reinforcement strips, which are cut cross-grain from
scrap balsa. Install these in place on the underside of the existing
sheeting in the damaged area using cyanoacrylate glue. Hold the
reinforcement strips in place using the custom-made holding tool,
which is shown, until the cyanoacrylate cures.
If the area to be repaired is too close to a rib, spar, or other
support, make a ledge using 1⁄4 balsa fit to contour and glue it in
place, leaving room for the replacement balsa to fit flush when
installed. Now the damaged area is prepared for new sheeting.
Place a piece of aluminum foil over the prepared hole. While
holding the foil so it does not move, trace the edges of the hole
with your finger and make a visible crease at all edges.
Carefully place and hold the aluminum foil over the replacement
balsa stock, being careful not to smooth out any of the creases.
(To hold it, you can press two fingers on the foil inside the traced
area or use tape on the outer edges and/or T-pins placed out of the
way of the pounce wheel.)
A pounce wheel is a small, spurlike tool that is used to transfer
patterns to wood. While holding the aluminum foil firmly in
place, run this tool along the edge of each traced mark. If you are
unable to locate a pounce wheel, you can make a series of pin
pricks along the creases. It produces the same effect but takes
longer.
Remove the foil from the balsa, and then cut along the dotted
lines left in the wood. Make the cross-grain cuts first. Use light
pressure on the knife blade for these cross-grain slices, and make
several passes with the knife until it cuts cleanly through the
balsa. If you try to make the cross-grain cuts with one knife pass,
the result might be a split part.
Carefully sand the edges of this replacement part until it fits
perfectly inside the prepared area. Sandpaper cuts quickly, so
check your progress after one or two passes to make sure that you
are not removing too much material.
If the damaged section is in a curved portion of the wing, such
as the LE area, you may need to bend the replacement panel
slightly to fit by lightly dampening the panel with water on the
outside before gluing. To do that, dip your fingers in water and
shake off the excess, and then lightly rub the outside surface of
the insert. Don’t saturate the wood; wet balsa warps and does not
glue well.
Install the replacement part using a yellow wood glue (such as
an aliphatic type) and remove any excess glue using a damp paper
towel. You can use small weights to hold the replacement part in
place on curved areas. Use plastic sheeting to keep the glue from
sticking to your weights while it sets.
You should allow the adhesive to dry for several hours before
sanding. You can use five-minute epoxy here, but it is more
difficult to sand smooth. The more time and care you take in
preparation, the better the fit will be.
After the glue has dried and the surface has been sanded to
your satisfaction, there may still be some small gaps in the seam
between the wing and the patch. You can fill these with a vinyl
spackling compound. When the spackling is dry, it is simple to
block-sand even with the surface.
At this point you can re-cover the repaired area with a heatshrink
film that closely matches the original finish.
Additional Thoughts: The custom holding tool shown was made
from some small-diameter music wire. It was bent in such a
manner that it allowed the tool to splice pieces in place under the
sheeting while the glue cured.
I have only been successful in locating pounce wheels at
Micro-Mark; they are $19.95 for a set of three (item 15200). Visit
the company online at www.micromark.com. MA
Steven Hunt
Box 1152
Evansville WY 82636
[email protected]
Repair any internal damage to ribs before proceeding. The hole
is shown ready for the patch.
Install the reinforcement strips using the custom wire tool and
cyanoacrylate glue. They form a sort of "shelf."
Place aluminum foil over the replacement balsa stock—being
careful not to smooth any of the creases—then run the pounce
wheel around the creased edge.
Place a piece of aluminum foil over the prepared hole. Trace
the edges of the hole with your finger, making a visible crease
at all edges.
With the aluminum foil removed, you can easily see the marked
area that will become the patch piece.
Carefully cut the patch along the outside of the marked lines
with the modeling knife. Leave some material to allow a perfect
fit with some sanding.
Sand and test-fit the patch until it fits the prepared hole
seamlessly. Take your time; a perfect fit will yield a stronger joint.
Re-cover the wing in the repaired area using a matching color
of heat-shrink film.
A closer look at the pounce wheel and custom-made wire tools
for holding the balsa reinforcement pieces in place.
Use filler or multiple thin coats of epoxy to fill voids on the
patch perimeter. Sand the area perfectly smooth.
