Re: [bolger] Fourth times the charm (was aluminum laminate)
Lead pouring pictures are at the bottom of
http://derbyrm.mystarband.net/Dayawl.html
Besides spattering lead all over, the camera battery went flat and the
propane cylinder went empty. Sometimes Sisyphus was the lucky one.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
http://derbyrm.mystarband.net/Dayawl.html
Besides spattering lead all over, the camera battery went flat and the
propane cylinder went empty. Sometimes Sisyphus was the lucky one.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
----- Original Message -----
From: "Roger Derby" <derbyrm@...>
> I spent this morning melting and pouring lead, then digging it out and
> starting over. Quite educational. Molten lead has an incredibly low
> viscosity. If the bottom of the cavity is not very well sealed, it WILL
run
> out, fall to the floor, and splash. The first time, I relied on the
weight
> of the CB to hold it down -- nah. Wood floats! (Actually, on molten
lead,
> everything floats.) The second, third, and fourth times featured
increasing
> attention to having the back side sealed with flat wood, faced with tin
and
> very well clamped.
>
> For others who might try this, I suggest long pants and boots. I didn't
get
> burned by the splashes, but that was only luck.
>
> Pictures soon.
is "wieldable," should be "weldable." D--n spell checker.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
----- Original Message -----
From: "Roger Derby" <derbyrm@...>
>
> Re: another thread, 6061 aluminum alloy is the wieldable stuff used for
> castings. 2024 is the sheet metal used for skinning structures; e.g.
wings.
Ben, In a short time I'll be able to weigh the Chebacco CB, built to PCB's
specification, so you don't need to calculate. I just need to plane down
the lead's meniscus and seal the CB with glass and epoxy first. -- oops.
Scrub that. As is it weighs on the order of 42 lbs ±3 lbs with the CB about
27" below the pivot. (My scale quits at 25 lbs. A 2:1 balance puts it over
that with the balance beam's tare weight, and the 3:1 I rigged is too rough
to trust.)
I spent this morning melting and pouring lead, then digging it out and
starting over. Quite educational. Molten lead has an incredibly low
viscosity. If the bottom of the cavity is not very well sealed, it WILL run
out, fall to the floor, and splash. The first time, I relied on the weight
of the CB to hold it down -- nah. Wood floats! (Actually, on molten lead,
everything floats.) The second, third, and fourth times featured increasing
attention to having the back side sealed with flat wood, faced with tin and
very well clamped.
For others who might try this, I suggest long pants and boots. I didn't get
burned by the splashes, but that was only luck.
Pictures soon.
Re: another thread, 6061 aluminum alloy is the wieldable stuff used for
castings. 2024 is the sheet metal used for skinning structures; e.g. wings.
There are many alloys and many are terrible things to work with; e.g. 1100,
the pure stuff is like trying to machine bubble gum.
History footnote: In the 1940s (WWII) FDR raised civilian morale by holding
"Scrap Aluminum Drives" to build airplanes. Even though aluminum cookware
was relatively precious at the time, many housewives dutifully contributed
their pots and pans. The contributions went straight to the scrap pile.
Airplanes need proper alloys and one doesn't get them from the horrible
mish-mash of metals in the scrap cookware collected.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
specification, so you don't need to calculate. I just need to plane down
the lead's meniscus and seal the CB with glass and epoxy first. -- oops.
Scrub that. As is it weighs on the order of 42 lbs ±3 lbs with the CB about
27" below the pivot. (My scale quits at 25 lbs. A 2:1 balance puts it over
that with the balance beam's tare weight, and the 3:1 I rigged is too rough
to trust.)
I spent this morning melting and pouring lead, then digging it out and
starting over. Quite educational. Molten lead has an incredibly low
viscosity. If the bottom of the cavity is not very well sealed, it WILL run
out, fall to the floor, and splash. The first time, I relied on the weight
of the CB to hold it down -- nah. Wood floats! (Actually, on molten lead,
everything floats.) The second, third, and fourth times featured increasing
attention to having the back side sealed with flat wood, faced with tin and
very well clamped.
For others who might try this, I suggest long pants and boots. I didn't get
burned by the splashes, but that was only luck.
Pictures soon.
Re: another thread, 6061 aluminum alloy is the wieldable stuff used for
castings. 2024 is the sheet metal used for skinning structures; e.g. wings.
There are many alloys and many are terrible things to work with; e.g. 1100,
the pure stuff is like trying to machine bubble gum.
History footnote: In the 1940s (WWII) FDR raised civilian morale by holding
"Scrap Aluminum Drives" to build airplanes. Even though aluminum cookware
was relatively precious at the time, many housewives dutifully contributed
their pots and pans. The contributions went straight to the scrap pile.
Airplanes need proper alloys and one doesn't get them from the horrible
mish-mash of metals in the scrap cookware collected.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
----- Original Message -----
From: "bh100014" <ben.ho@...>
> I assume a solid plate will be much heavier than aluminum/wood, but
> I will have to calculate the actual weights and compare the two
> approaches. I've seen solid galvanized iron CB's, but there the
> design is to also use it as sort of a swing keel, so the weight is
> intentional. The Chebacco's CB per plan is wood with lead, so I
> wouldn't want to have something much heavier than the designed
> weight. Also am not sure if 5/8" aluminum is solid enough that it
> won't bent when running aground with lateral speed.