It's a wing keel; was pouring lead frustrations
Okay, gang, here it goes again. Did this last night and then managed
to lose the message. Somehow seems appropriate. Anyway, with the help
of your encouragement and suggestions, the two sides of the wing keel
for my 30-footer were successfully poured on Sunday. Time of birth
after the labored delivery was 5:25 p.m. Weight about 1,000
pounds.
As some may recall, I unsuccessful it trying to melt lead in an 18-
inch diameter tank with a 160,000 BTU propane burner, known locally
as a fish cooker. I thought a 9-hour marathon burn had only melted 30-
50 pounds. But it turned out, when the unmelted lead was removed,
that 150-200 pounds had actually melted. Also, the tank did not have
a double bottom, as had been suggested by a friend. From your
suggestions and this, I concluded the setup was on the verge of being
sufficient, but either needed a bigger burner, insulation, or both.
Well, a bigger burner isn't readily available in Tallahassee, Fl.,
and the tank is too narrow to fit two burners underneath. I got some
unbacked, unfaced noncombustible (backing or facing material will
burn) insulation from Home Depot. It's about 3" thick. It was wrapped
around once, and another piece was cut for the top. Since it had
rained and the interior of the tank was wet, I heated gently for an
hour to dry things out and then cranked it up full blast. After
another hour, most the 150-200 pounds in the tank was melted. I added
the rest, a few pieces at a time, and it was all melted in another
three hours. A camping propane stove under the outlet pipe for 15
minutes melted the lead there, and then the gate valve was turned and
the lead flowed. It seemed almost unbelievable after the earlier
problems. The actual pouring took less than five minutes, and another
50 or so pounds was poured into an old pot to be saved for future
projects.
Some observations:
I think the tank was too wide for this type of burner; a 12-
inch tank might have worked without the insulation. On the other
hand, the insulation made the whole setup much safer to work with
because of the reduced risk of burns from accidentally touching the
sides.
I forget who suggested switching propane tanks because they
get very cold to the touch as they empty and that might affect the
flame temperature. I switched tanks (I had two) back and forth twice
during the burn, but can't make any observations on how much that
helped.
Although 1,000 pounds, plus or minus, was poured (minus
about 200 pounds put in the mold cold to stabilize it and keep it
level during the pour), it was poured in two pieces, one wing for
either side of the main keel. The mold was built as one piece divided
into two sections. The wings are about three feet long, about 1 foot
wide at the widest and the thickness ranges from about one inch at
the ends to about four inches at the deepest part. Scantlings for the
mold were: three 1/4-inch lawyers of ply for the curved bottom, and
the same for the curved outer sides. The inner sides, which are
straight, are two layers on 3/4-inch ply. The ends are one layer of
3/4 inch ply. It was all glued together with either epoxy or
polyurethane glues, and then a bunch of decking screws added for
reinforcement. All the inside joints were covered with a heat
resistant fireplace caulk, rated to withstand more than 1,000
degrees. Some plywood slats were screwed across the top to keep the
sides from spreading. It all held together. I was surprised in that
the lead seemed to solidify in a couple of minutes. The wood smoked
for about 20 minutes.
Safety is important! I wore heavy work shoes, blue jeans
(we actually had a very rare cool day) and heavy leather fireplace
gloves. The gate valve leaked and sent up a small geyser of hot lead,
which fortunately missed me and sealed it self in a minute or so, but
I was glad to have the gloves and other protection .
Once again, thanks for everyone's encouragement and suggestions.
You're all godparents....
Gary Blankenship
Tallahassee, FL
to lose the message. Somehow seems appropriate. Anyway, with the help
of your encouragement and suggestions, the two sides of the wing keel
for my 30-footer were successfully poured on Sunday. Time of birth
after the labored delivery was 5:25 p.m. Weight about 1,000
pounds.
As some may recall, I unsuccessful it trying to melt lead in an 18-
inch diameter tank with a 160,000 BTU propane burner, known locally
as a fish cooker. I thought a 9-hour marathon burn had only melted 30-
50 pounds. But it turned out, when the unmelted lead was removed,
that 150-200 pounds had actually melted. Also, the tank did not have
a double bottom, as had been suggested by a friend. From your
suggestions and this, I concluded the setup was on the verge of being
sufficient, but either needed a bigger burner, insulation, or both.
Well, a bigger burner isn't readily available in Tallahassee, Fl.,
and the tank is too narrow to fit two burners underneath. I got some
unbacked, unfaced noncombustible (backing or facing material will
burn) insulation from Home Depot. It's about 3" thick. It was wrapped
around once, and another piece was cut for the top. Since it had
rained and the interior of the tank was wet, I heated gently for an
hour to dry things out and then cranked it up full blast. After
another hour, most the 150-200 pounds in the tank was melted. I added
the rest, a few pieces at a time, and it was all melted in another
three hours. A camping propane stove under the outlet pipe for 15
minutes melted the lead there, and then the gate valve was turned and
the lead flowed. It seemed almost unbelievable after the earlier
problems. The actual pouring took less than five minutes, and another
50 or so pounds was poured into an old pot to be saved for future
projects.
Some observations:
I think the tank was too wide for this type of burner; a 12-
inch tank might have worked without the insulation. On the other
hand, the insulation made the whole setup much safer to work with
because of the reduced risk of burns from accidentally touching the
sides.
I forget who suggested switching propane tanks because they
get very cold to the touch as they empty and that might affect the
flame temperature. I switched tanks (I had two) back and forth twice
during the burn, but can't make any observations on how much that
helped.
Although 1,000 pounds, plus or minus, was poured (minus
about 200 pounds put in the mold cold to stabilize it and keep it
level during the pour), it was poured in two pieces, one wing for
either side of the main keel. The mold was built as one piece divided
into two sections. The wings are about three feet long, about 1 foot
wide at the widest and the thickness ranges from about one inch at
the ends to about four inches at the deepest part. Scantlings for the
mold were: three 1/4-inch lawyers of ply for the curved bottom, and
the same for the curved outer sides. The inner sides, which are
straight, are two layers on 3/4-inch ply. The ends are one layer of
3/4 inch ply. It was all glued together with either epoxy or
polyurethane glues, and then a bunch of decking screws added for
reinforcement. All the inside joints were covered with a heat
resistant fireplace caulk, rated to withstand more than 1,000
degrees. Some plywood slats were screwed across the top to keep the
sides from spreading. It all held together. I was surprised in that
the lead seemed to solidify in a couple of minutes. The wood smoked
for about 20 minutes.
Safety is important! I wore heavy work shoes, blue jeans
(we actually had a very rare cool day) and heavy leather fireplace
gloves. The gate valve leaked and sent up a small geyser of hot lead,
which fortunately missed me and sealed it self in a minute or so, but
I was glad to have the gloves and other protection .
Once again, thanks for everyone's encouragement and suggestions.
You're all godparents....
Gary Blankenship
Tallahassee, FL