GLANCING
through the pages of
any of today’s
model airplane
magazines quickly
shows that electric
power has largely
superseded piston
power. It has
practically wiped
out glow engines
smaller than .15 in
size and made CO2
motors obsolete.
Yet many of us
fliers, old and
young, keep using
our piston engines.
Our motivations
may vary, but as
John Allen Kennedy
(Shreveport,
Louisiana) once told
me, “Piston power
possesses
personality!”
That got me
thinking. Yes,
“personality”! I’ve
owned and operated
hundreds of model
engines since my
first pre-World War
II Brown Junior. As
I look back on those,
I can distinctly
remember the
“character” of many.
Some piston
engines were mean,
inimical, and
uncooperative.
Others were dull
plodders that needed
much attention and
coaxing to operate.
But a few memorable ones stand out in my recollection. Their
“personalities” are unforgettable.
We users of spark-ignition model engines of the 1930s and early
1940s had to contend with weak batteries and poor “condensers,”
oily “contact points,” and fouled spark plugs. Those issues caused
many frustrations.
Manufacturing quality varied considerably too. That’s why my
Forster .29 made a deeply favorable impression on me; it seemed to
want to run—and keep running as long as its fuel lasted. That
engine’s fine-threaded needle valve and easily adjustable point gap
made for simple and positive settings, and I never doubted my
Forster .29’s reliability.
After WW II, a plethora of model power plants came on the
market. A few of those stand out in my memory, such as the Arden
.099s, DeLong .30s, and Super Cyclones. They were great sparkignition
engines and I liked them a lot.
Model engines with “personality”
June 2009 93
The Engine Shop Joe Wagner | [email protected]
Also included in this column:
• Starting small diesels
• Homemade gaskets
This 1941 Forster .29 sparker was the
first truly cooperative model engine that
the author owned. It had no quirks.
The 1949 Baby Spitfire .045 was neither
the first 1/2A engine nor the best, but its
friendliness and low cost made up for its
fragility.
1956 Johnson .29s seemed especially eager to fly. Foxes, Vecos,
and K&B .29s of that era were good, but Johnsons surpassed
them in ambition.
06sig3.QXD 4/22/09 12:43 PM Page 93
94 MODEL AVIATION
Above: Clarence Lee’s customized version
of the Veco/K&B RC .19 was the first
amiable RC model airplane engine that the
author owned. One-flip starts were normal.
Left: The smallest RC diesel available
today—the PAW .03—spins a wide range of
propeller sizes and responds readily to its
throttle.
Below: Homemade gaskets require no
special materials. A sturdy draftsman’s
compass equipped with a sharpened inch of
music wire does the cutting.
Then the glow plug appeared in 1946, and model engine makers
didn’t know what to do about that radical new development at first.
But they soon took the obvious path and issued glow versions of
their earlier sparkers without their “ignition points,” including
Bantams, K&B Torpedos, and Atwood Champions—and sold many.
A few farsighted innovators could see that, without needing to
carry heavy batteries and spark coils in flight, it had become possible
to make tiny model power plants. Among those visionaries was Mel
Anderson, who designed the justly famous Super Cyclone.
Using exactly half of the bore and stroke of the Baby Cyclone
.36—the first model airplane engine he was involved in producing,
more than a decade earlier—Mel came up with the Baby Spitfire .045.
As a pioneering 1/2A engine, the “Baby Spit” had a drawback or
two. Its small size made it fragile—especially the needle and radial
mounting lugs. But it started readily, wasn’t finicky in its settings, and
had a minimal cost. I enjoyed many flights with Baby Spitfirepowered
Dakotas and Sioux and remember what an agreeable engine
it was.
I did considerable CL Stunt (Precision Aerobatics) flying in the
1950s. Engines of choice for that were Foxes, Vecos, and K&Bs.
They did well, both in performance and in sales, but I can’t recall
any especially memorable qualities they had. The Johnson was
something else.
It was derived from the earlier Orwick line of CL power plants.
The Johnson .29 went through a lengthy development period, but it
brought results. I owned several Johnsons, and still have two, and
they have all seemed “rarin’ to go” when installed in one of my
Chief or Squaw aircraft.
I’m not the only one who got that impression, either. No Johnson
engines have been made in the last 45 years, but existing specimens
are still much in demand for flying in Old-Time Stunt events.
Variable-speed engines for RC models had a long gestation. I
took part in that development and still have a couple of my
prototypes. I can’t remember any model engine I owned before the
Lee Custom .19 that had a truly friendly disposition.
With only minimal “tweaking” of its Perry carburetor, I could get
reliable idle speeds as low as 1,800 rpm with almost instant
acceleration to top speed. After I primed my Lee .19 with a shot of
raw fuel into its exhaust, it hardly ever needed more than a single
flip of its propeller to get perking.
Model RC engines in the premuffler era often featured coupled
throttle barrels and exhaust baffles. This setup helped provide
reliable low idle speeds, because the restricted exhaust outflow kept
heat in the cylinder and minimized “flameouts.” Then the wide-open
06sig3.QXD 4/22/09 12:48 PM Page 94
exhaust, at full power, let excess fuel that had
accumulated in the case during idling blast
out swiftly and prevented hesitation in
returning to top rpm.
Another of my RC engines that I classify
as exceptionally friendly is the Progress Aero
Works (PAW) .03 diesel. Because of its
variable compression, this little gem can
happily run turning propellers from 5 x 2 to
10 x 4! However, as do most model diesels of
less than .10 displacement, the PAW .03
requires a different starting method than
larger sizes do.
Standard diesel starting technique calls for
a high initial compression setting to ignite the
fuel-oil-air mixture in a cold engine. Then as
soon as the engine begins to run and warm up,
it’s necessary to back off the compression,
gradually, to prevent premature ignition and
overheating and excessive stresses that result
from that.
But small diesels often start best with a
reduced compression setting. That’s because
the “headspace” between the piston crown
and the underside of the contrapiston at the
top of the stroke is so small—less than 1/64
inch sometimes. The mere thickness of a wet
fuel-oil film in the combustion chamber can
act as a compression booster.
I begin starting my PAW .03s (I own
several) at a low compression setting, keeping
my left hand on the adjusting lever as I handflip
the propeller. I gradually increase the
compression until the engine fires. Then I
quickly increase the compression further, until
the firing smoothes out and the exhaust oil
emerges no darker than a light brown. I
seldom need to change needle settings.
One topic I often get queries from readers
about is replacement gaskets. These can be
difficult to find, even for some modern
engines, and they’re almost impossible to buy
for old-time power plants. Material for do-ityourself
(DIY) gasket makers seems to have
gone off the market too. However, I’ve been
making my own model engine replacement
gaskets for years.
For everything except head gaskets, I use
“card stock” material from the drop-out-inyour-
lap subscription and ad cards that most
of today’s magazines contain. For head
gaskets, I use thin aluminum sheet from
disposable pie pans. I cut my gaskets with a
modified drafting compass—one that has a
cutting blade on one “leg” instead of a
graphite point.
“Ring-type” gaskets work fine for most
model engine applications. It’s unnecessary
for gaskets to cover the entire mating surface
area, including screw holes. I’ve found that
eliminating the little perforated “ears” helps
sealing efficiency; it lets the gasket compress
evenly around its perimeter, instead of mostly
around the screw-hole areas.
I made the “blade” in my DIY gasket
cutter from .080 (2mm) music wire. That’s
hardened steel, but not quite hard enough to
retain an extremely sharp edge. So I grind the
cutting edge to the approximate shape while
holding the wire in a pin vise. Then I
reharden the point.
To do that, I set an ice cube on my
workbench. I light my small butane torch and
heat the end 1/4 inch or so of the roughground
music wire to a bright, cherry-red
glow.
I keep it at that temperature for
approximately 30 seconds, and then plunge it
quickly onto the ice cube. That provides an
instant “quench,” which maximizes the
point’s hardness. After that, I carefully grind,
sharpen, and hone the cutting edge, being
careful never to allow the razor-thin edge to
get hot enough to lose any of its hardness.
This gasket-cutting process requires many
cutter rotations. I use either a hard plywood
backing under the gasket material or, better
yet, a flat sheet of aircraft aluminum.
A relatively unyielding undersurface
prevents the gasket material from embossing
under the cutter’s numerous passes. It also
stops the compass’s center point from digging
itself deeper as the cutting process continues.
Properly done, slowly and surely, gaskets
cut this way will have smooth edges and lay
flat. If yours aren’t like that, resharpen your
cutting point and try again, since the material
is cheap.
Before installing my replacement gaskets,
I soak them in castor oil for a few minutes.
That provides extra sealing ability and, yes,
that also applies to the aluminum gaskets.
And remember: “Piston power possesses
personality!” MA
Edition: Model Aviation - 2009/06
Page Numbers: 93,94,96
Edition: Model Aviation - 2009/06
Page Numbers: 93,94,96
GLANCING
through the pages of
any of today’s
model airplane
magazines quickly
shows that electric
power has largely
superseded piston
power. It has
practically wiped
out glow engines
smaller than .15 in
size and made CO2
motors obsolete.
Yet many of us
fliers, old and
young, keep using
our piston engines.
Our motivations
may vary, but as
John Allen Kennedy
(Shreveport,
Louisiana) once told
me, “Piston power
possesses
personality!”
That got me
thinking. Yes,
“personality”! I’ve
owned and operated
hundreds of model
engines since my
first pre-World War
II Brown Junior. As
I look back on those,
I can distinctly
remember the
“character” of many.
Some piston
engines were mean,
inimical, and
uncooperative.
Others were dull
plodders that needed
much attention and
coaxing to operate.
But a few memorable ones stand out in my recollection. Their
“personalities” are unforgettable.
We users of spark-ignition model engines of the 1930s and early
1940s had to contend with weak batteries and poor “condensers,”
oily “contact points,” and fouled spark plugs. Those issues caused
many frustrations.
Manufacturing quality varied considerably too. That’s why my
Forster .29 made a deeply favorable impression on me; it seemed to
want to run—and keep running as long as its fuel lasted. That
engine’s fine-threaded needle valve and easily adjustable point gap
made for simple and positive settings, and I never doubted my
Forster .29’s reliability.
After WW II, a plethora of model power plants came on the
market. A few of those stand out in my memory, such as the Arden
.099s, DeLong .30s, and Super Cyclones. They were great sparkignition
engines and I liked them a lot.
Model engines with “personality”
June 2009 93
The Engine Shop Joe Wagner | [email protected]
Also included in this column:
• Starting small diesels
• Homemade gaskets
This 1941 Forster .29 sparker was the
first truly cooperative model engine that
the author owned. It had no quirks.
The 1949 Baby Spitfire .045 was neither
the first 1/2A engine nor the best, but its
friendliness and low cost made up for its
fragility.
1956 Johnson .29s seemed especially eager to fly. Foxes, Vecos,
and K&B .29s of that era were good, but Johnsons surpassed
them in ambition.
06sig3.QXD 4/22/09 12:43 PM Page 93
94 MODEL AVIATION
Above: Clarence Lee’s customized version
of the Veco/K&B RC .19 was the first
amiable RC model airplane engine that the
author owned. One-flip starts were normal.
Left: The smallest RC diesel available
today—the PAW .03—spins a wide range of
propeller sizes and responds readily to its
throttle.
Below: Homemade gaskets require no
special materials. A sturdy draftsman’s
compass equipped with a sharpened inch of
music wire does the cutting.
Then the glow plug appeared in 1946, and model engine makers
didn’t know what to do about that radical new development at first.
But they soon took the obvious path and issued glow versions of
their earlier sparkers without their “ignition points,” including
Bantams, K&B Torpedos, and Atwood Champions—and sold many.
A few farsighted innovators could see that, without needing to
carry heavy batteries and spark coils in flight, it had become possible
to make tiny model power plants. Among those visionaries was Mel
Anderson, who designed the justly famous Super Cyclone.
Using exactly half of the bore and stroke of the Baby Cyclone
.36—the first model airplane engine he was involved in producing,
more than a decade earlier—Mel came up with the Baby Spitfire .045.
As a pioneering 1/2A engine, the “Baby Spit” had a drawback or
two. Its small size made it fragile—especially the needle and radial
mounting lugs. But it started readily, wasn’t finicky in its settings, and
had a minimal cost. I enjoyed many flights with Baby Spitfirepowered
Dakotas and Sioux and remember what an agreeable engine
it was.
I did considerable CL Stunt (Precision Aerobatics) flying in the
1950s. Engines of choice for that were Foxes, Vecos, and K&Bs.
They did well, both in performance and in sales, but I can’t recall
any especially memorable qualities they had. The Johnson was
something else.
It was derived from the earlier Orwick line of CL power plants.
The Johnson .29 went through a lengthy development period, but it
brought results. I owned several Johnsons, and still have two, and
they have all seemed “rarin’ to go” when installed in one of my
Chief or Squaw aircraft.
I’m not the only one who got that impression, either. No Johnson
engines have been made in the last 45 years, but existing specimens
are still much in demand for flying in Old-Time Stunt events.
Variable-speed engines for RC models had a long gestation. I
took part in that development and still have a couple of my
prototypes. I can’t remember any model engine I owned before the
Lee Custom .19 that had a truly friendly disposition.
With only minimal “tweaking” of its Perry carburetor, I could get
reliable idle speeds as low as 1,800 rpm with almost instant
acceleration to top speed. After I primed my Lee .19 with a shot of
raw fuel into its exhaust, it hardly ever needed more than a single
flip of its propeller to get perking.
Model RC engines in the premuffler era often featured coupled
throttle barrels and exhaust baffles. This setup helped provide
reliable low idle speeds, because the restricted exhaust outflow kept
heat in the cylinder and minimized “flameouts.” Then the wide-open
06sig3.QXD 4/22/09 12:48 PM Page 94
exhaust, at full power, let excess fuel that had
accumulated in the case during idling blast
out swiftly and prevented hesitation in
returning to top rpm.
Another of my RC engines that I classify
as exceptionally friendly is the Progress Aero
Works (PAW) .03 diesel. Because of its
variable compression, this little gem can
happily run turning propellers from 5 x 2 to
10 x 4! However, as do most model diesels of
less than .10 displacement, the PAW .03
requires a different starting method than
larger sizes do.
Standard diesel starting technique calls for
a high initial compression setting to ignite the
fuel-oil-air mixture in a cold engine. Then as
soon as the engine begins to run and warm up,
it’s necessary to back off the compression,
gradually, to prevent premature ignition and
overheating and excessive stresses that result
from that.
But small diesels often start best with a
reduced compression setting. That’s because
the “headspace” between the piston crown
and the underside of the contrapiston at the
top of the stroke is so small—less than 1/64
inch sometimes. The mere thickness of a wet
fuel-oil film in the combustion chamber can
act as a compression booster.
I begin starting my PAW .03s (I own
several) at a low compression setting, keeping
my left hand on the adjusting lever as I handflip
the propeller. I gradually increase the
compression until the engine fires. Then I
quickly increase the compression further, until
the firing smoothes out and the exhaust oil
emerges no darker than a light brown. I
seldom need to change needle settings.
One topic I often get queries from readers
about is replacement gaskets. These can be
difficult to find, even for some modern
engines, and they’re almost impossible to buy
for old-time power plants. Material for do-ityourself
(DIY) gasket makers seems to have
gone off the market too. However, I’ve been
making my own model engine replacement
gaskets for years.
For everything except head gaskets, I use
“card stock” material from the drop-out-inyour-
lap subscription and ad cards that most
of today’s magazines contain. For head
gaskets, I use thin aluminum sheet from
disposable pie pans. I cut my gaskets with a
modified drafting compass—one that has a
cutting blade on one “leg” instead of a
graphite point.
“Ring-type” gaskets work fine for most
model engine applications. It’s unnecessary
for gaskets to cover the entire mating surface
area, including screw holes. I’ve found that
eliminating the little perforated “ears” helps
sealing efficiency; it lets the gasket compress
evenly around its perimeter, instead of mostly
around the screw-hole areas.
I made the “blade” in my DIY gasket
cutter from .080 (2mm) music wire. That’s
hardened steel, but not quite hard enough to
retain an extremely sharp edge. So I grind the
cutting edge to the approximate shape while
holding the wire in a pin vise. Then I
reharden the point.
To do that, I set an ice cube on my
workbench. I light my small butane torch and
heat the end 1/4 inch or so of the roughground
music wire to a bright, cherry-red
glow.
I keep it at that temperature for
approximately 30 seconds, and then plunge it
quickly onto the ice cube. That provides an
instant “quench,” which maximizes the
point’s hardness. After that, I carefully grind,
sharpen, and hone the cutting edge, being
careful never to allow the razor-thin edge to
get hot enough to lose any of its hardness.
This gasket-cutting process requires many
cutter rotations. I use either a hard plywood
backing under the gasket material or, better
yet, a flat sheet of aircraft aluminum.
A relatively unyielding undersurface
prevents the gasket material from embossing
under the cutter’s numerous passes. It also
stops the compass’s center point from digging
itself deeper as the cutting process continues.
Properly done, slowly and surely, gaskets
cut this way will have smooth edges and lay
flat. If yours aren’t like that, resharpen your
cutting point and try again, since the material
is cheap.
Before installing my replacement gaskets,
I soak them in castor oil for a few minutes.
That provides extra sealing ability and, yes,
that also applies to the aluminum gaskets.
And remember: “Piston power possesses
personality!” MA
Edition: Model Aviation - 2009/06
Page Numbers: 93,94,96
GLANCING
through the pages of
any of today’s
model airplane
magazines quickly
shows that electric
power has largely
superseded piston
power. It has
practically wiped
out glow engines
smaller than .15 in
size and made CO2
motors obsolete.
Yet many of us
fliers, old and
young, keep using
our piston engines.
Our motivations
may vary, but as
John Allen Kennedy
(Shreveport,
Louisiana) once told
me, “Piston power
possesses
personality!”
That got me
thinking. Yes,
“personality”! I’ve
owned and operated
hundreds of model
engines since my
first pre-World War
II Brown Junior. As
I look back on those,
I can distinctly
remember the
“character” of many.
Some piston
engines were mean,
inimical, and
uncooperative.
Others were dull
plodders that needed
much attention and
coaxing to operate.
But a few memorable ones stand out in my recollection. Their
“personalities” are unforgettable.
We users of spark-ignition model engines of the 1930s and early
1940s had to contend with weak batteries and poor “condensers,”
oily “contact points,” and fouled spark plugs. Those issues caused
many frustrations.
Manufacturing quality varied considerably too. That’s why my
Forster .29 made a deeply favorable impression on me; it seemed to
want to run—and keep running as long as its fuel lasted. That
engine’s fine-threaded needle valve and easily adjustable point gap
made for simple and positive settings, and I never doubted my
Forster .29’s reliability.
After WW II, a plethora of model power plants came on the
market. A few of those stand out in my memory, such as the Arden
.099s, DeLong .30s, and Super Cyclones. They were great sparkignition
engines and I liked them a lot.
Model engines with “personality”
June 2009 93
The Engine Shop Joe Wagner | [email protected]
Also included in this column:
• Starting small diesels
• Homemade gaskets
This 1941 Forster .29 sparker was the
first truly cooperative model engine that
the author owned. It had no quirks.
The 1949 Baby Spitfire .045 was neither
the first 1/2A engine nor the best, but its
friendliness and low cost made up for its
fragility.
1956 Johnson .29s seemed especially eager to fly. Foxes, Vecos,
and K&B .29s of that era were good, but Johnsons surpassed
them in ambition.
06sig3.QXD 4/22/09 12:43 PM Page 93
94 MODEL AVIATION
Above: Clarence Lee’s customized version
of the Veco/K&B RC .19 was the first
amiable RC model airplane engine that the
author owned. One-flip starts were normal.
Left: The smallest RC diesel available
today—the PAW .03—spins a wide range of
propeller sizes and responds readily to its
throttle.
Below: Homemade gaskets require no
special materials. A sturdy draftsman’s
compass equipped with a sharpened inch of
music wire does the cutting.
Then the glow plug appeared in 1946, and model engine makers
didn’t know what to do about that radical new development at first.
But they soon took the obvious path and issued glow versions of
their earlier sparkers without their “ignition points,” including
Bantams, K&B Torpedos, and Atwood Champions—and sold many.
A few farsighted innovators could see that, without needing to
carry heavy batteries and spark coils in flight, it had become possible
to make tiny model power plants. Among those visionaries was Mel
Anderson, who designed the justly famous Super Cyclone.
Using exactly half of the bore and stroke of the Baby Cyclone
.36—the first model airplane engine he was involved in producing,
more than a decade earlier—Mel came up with the Baby Spitfire .045.
As a pioneering 1/2A engine, the “Baby Spit” had a drawback or
two. Its small size made it fragile—especially the needle and radial
mounting lugs. But it started readily, wasn’t finicky in its settings, and
had a minimal cost. I enjoyed many flights with Baby Spitfirepowered
Dakotas and Sioux and remember what an agreeable engine
it was.
I did considerable CL Stunt (Precision Aerobatics) flying in the
1950s. Engines of choice for that were Foxes, Vecos, and K&Bs.
They did well, both in performance and in sales, but I can’t recall
any especially memorable qualities they had. The Johnson was
something else.
It was derived from the earlier Orwick line of CL power plants.
The Johnson .29 went through a lengthy development period, but it
brought results. I owned several Johnsons, and still have two, and
they have all seemed “rarin’ to go” when installed in one of my
Chief or Squaw aircraft.
I’m not the only one who got that impression, either. No Johnson
engines have been made in the last 45 years, but existing specimens
are still much in demand for flying in Old-Time Stunt events.
Variable-speed engines for RC models had a long gestation. I
took part in that development and still have a couple of my
prototypes. I can’t remember any model engine I owned before the
Lee Custom .19 that had a truly friendly disposition.
With only minimal “tweaking” of its Perry carburetor, I could get
reliable idle speeds as low as 1,800 rpm with almost instant
acceleration to top speed. After I primed my Lee .19 with a shot of
raw fuel into its exhaust, it hardly ever needed more than a single
flip of its propeller to get perking.
Model RC engines in the premuffler era often featured coupled
throttle barrels and exhaust baffles. This setup helped provide
reliable low idle speeds, because the restricted exhaust outflow kept
heat in the cylinder and minimized “flameouts.” Then the wide-open
06sig3.QXD 4/22/09 12:48 PM Page 94
exhaust, at full power, let excess fuel that had
accumulated in the case during idling blast
out swiftly and prevented hesitation in
returning to top rpm.
Another of my RC engines that I classify
as exceptionally friendly is the Progress Aero
Works (PAW) .03 diesel. Because of its
variable compression, this little gem can
happily run turning propellers from 5 x 2 to
10 x 4! However, as do most model diesels of
less than .10 displacement, the PAW .03
requires a different starting method than
larger sizes do.
Standard diesel starting technique calls for
a high initial compression setting to ignite the
fuel-oil-air mixture in a cold engine. Then as
soon as the engine begins to run and warm up,
it’s necessary to back off the compression,
gradually, to prevent premature ignition and
overheating and excessive stresses that result
from that.
But small diesels often start best with a
reduced compression setting. That’s because
the “headspace” between the piston crown
and the underside of the contrapiston at the
top of the stroke is so small—less than 1/64
inch sometimes. The mere thickness of a wet
fuel-oil film in the combustion chamber can
act as a compression booster.
I begin starting my PAW .03s (I own
several) at a low compression setting, keeping
my left hand on the adjusting lever as I handflip
the propeller. I gradually increase the
compression until the engine fires. Then I
quickly increase the compression further, until
the firing smoothes out and the exhaust oil
emerges no darker than a light brown. I
seldom need to change needle settings.
One topic I often get queries from readers
about is replacement gaskets. These can be
difficult to find, even for some modern
engines, and they’re almost impossible to buy
for old-time power plants. Material for do-ityourself
(DIY) gasket makers seems to have
gone off the market too. However, I’ve been
making my own model engine replacement
gaskets for years.
For everything except head gaskets, I use
“card stock” material from the drop-out-inyour-
lap subscription and ad cards that most
of today’s magazines contain. For head
gaskets, I use thin aluminum sheet from
disposable pie pans. I cut my gaskets with a
modified drafting compass—one that has a
cutting blade on one “leg” instead of a
graphite point.
“Ring-type” gaskets work fine for most
model engine applications. It’s unnecessary
for gaskets to cover the entire mating surface
area, including screw holes. I’ve found that
eliminating the little perforated “ears” helps
sealing efficiency; it lets the gasket compress
evenly around its perimeter, instead of mostly
around the screw-hole areas.
I made the “blade” in my DIY gasket
cutter from .080 (2mm) music wire. That’s
hardened steel, but not quite hard enough to
retain an extremely sharp edge. So I grind the
cutting edge to the approximate shape while
holding the wire in a pin vise. Then I
reharden the point.
To do that, I set an ice cube on my
workbench. I light my small butane torch and
heat the end 1/4 inch or so of the roughground
music wire to a bright, cherry-red
glow.
I keep it at that temperature for
approximately 30 seconds, and then plunge it
quickly onto the ice cube. That provides an
instant “quench,” which maximizes the
point’s hardness. After that, I carefully grind,
sharpen, and hone the cutting edge, being
careful never to allow the razor-thin edge to
get hot enough to lose any of its hardness.
This gasket-cutting process requires many
cutter rotations. I use either a hard plywood
backing under the gasket material or, better
yet, a flat sheet of aircraft aluminum.
A relatively unyielding undersurface
prevents the gasket material from embossing
under the cutter’s numerous passes. It also
stops the compass’s center point from digging
itself deeper as the cutting process continues.
Properly done, slowly and surely, gaskets
cut this way will have smooth edges and lay
flat. If yours aren’t like that, resharpen your
cutting point and try again, since the material
is cheap.
Before installing my replacement gaskets,
I soak them in castor oil for a few minutes.
That provides extra sealing ability and, yes,
that also applies to the aluminum gaskets.
And remember: “Piston power possesses
personality!” MA