[bolger] Re: Lead shot in epoxy (was modern Light Schooner)
ghc <ghart-@...> wrote:
original article:http://www.egroups.com/group/bolger/?start=2026
packing
objects there is highly sorted and arranged packing, and there is
random
packing. You tend to get random packing, unless you are extremely
careful
and meticulous,i.e. place each object in one by one.
In random packing of spherical or nearly spherical objects, the void
volume
can range from about 28% (very, very, very difficult and rare) to about
52%
(very unstable). Simply pouring the stuff in will usually yield about
40% to
46% void volume. Vibrating or whacking the container with a hammer
will drop
the void volume to about 36% to 40%. The random packing of
non-spheroid
shapes tends to result in higher void volumes, as the non-spherical
objects
can be stable in quite open structures. Using a wide range of sizes
can help a
bit, but in practise only 1% to 2%.
If one wants lower void volumes than 36% to 40%, cast large lead ingots
that
are a reasonable match to the dimensions of the keel and place them
one by
one. That should yield void volumes of 10% to 20%.
Doug
(someone who spent way too much of his life packing particles into
containers)
original article:http://www.egroups.com/group/bolger/?start=2026
> 75% is what I thought - but I got more like 50% in practice.shot
>
> Gregg Carlson
>
> At 08:56 AM 1/27/2000 -0000, you wrote:
> >Hi,
> >
> >Just surfed some math sites and found that sphere packing (i.e.lead
> >packing) is a non-trivial problem that mathematicians are stillwrestling
> >with!packed
> >
> >There seems to be general agreement, though, that when spheres are
> >'grapefruit style' you get about 78% of the density of solid lead.In other
> >words, if you use lead shot in epoxy for ballast, add about 25% tothe
> >volume to get the equivalent of solid lead (give or take . . .)This is probably more detail than anyone would want (or need :)). When
> >
> >Bill
> >--bill.samson@...
packing
objects there is highly sorted and arranged packing, and there is
random
packing. You tend to get random packing, unless you are extremely
careful
and meticulous,i.e. place each object in one by one.
In random packing of spherical or nearly spherical objects, the void
volume
can range from about 28% (very, very, very difficult and rare) to about
52%
(very unstable). Simply pouring the stuff in will usually yield about
40% to
46% void volume. Vibrating or whacking the container with a hammer
will drop
the void volume to about 36% to 40%. The random packing of
non-spheroid
shapes tends to result in higher void volumes, as the non-spherical
objects
can be stable in quite open structures. Using a wide range of sizes
can help a
bit, but in practise only 1% to 2%.
If one wants lower void volumes than 36% to 40%, cast large lead ingots
that
are a reasonable match to the dimensions of the keel and place them
one by
one. That should yield void volumes of 10% to 20%.
Doug
(someone who spent way too much of his life packing particles into
containers)
75% is what I thought - but I got more like 50% in practice.
Gregg Carlson
At 08:56 AM 1/27/2000 -0000, you wrote:
Gregg Carlson
At 08:56 AM 1/27/2000 -0000, you wrote:
>Hi,
>
>Just surfed some math sites and found that sphere packing (i.e.lead shot
>packing) is a non-trivial problem that mathematicians are still wrestling
>with!
>
>There seems to be general agreement, though, that when spheres are packed
>'grapefruit style' you get about 78% of the density of solid lead. In other
>words, if you use lead shot in epoxy for ballast, add about 25% to the
>volume to get the equivalent of solid lead (give or take . . .)
>
>Bill
>--bill.samson@...
>
>Chebacco News can be viewed on:
>http://members.xoom.com/billsamson
>
>-----Original Message-----
>From: Robert N. Lundy <robert@...>
>To:bolger@egroups.com<bolger@egroups.com>
>Date: 27 January 2000 00:15
>Subject: [bolger] Re: modern Light Schooner
>
>
>>I've spent quite a bit of time studying the single handed schooner in BWAOM
>>and wonder if it is really that much easier. I actually thought it looked
>>somewhat more involved mainly for two reasons:
>>
>>1. The "removable" inboard rudder assembly looks straightforward in design,
>>but tricky to execute. Also, it makes an extra trunk one has to build.
>>
>>2. The hundred pound centerboard gives me "keel anxiety" over dealing with
>>that much lead.
>>
>>With that said, the two trickiest (to me anyway) parts of the building are
>>also what gives this boat a special place-its self righting and the inboard
>>rudder makes for a really elegant schooner look-not to mention you can
>sleep
>>inside of it.
>>
>>Someone with some "I is an engineer" training needs to give some thought to
>>the idea used by several folks to use epoxy and lead shot to cast really
>>heavy items. Think about it. There should be some nice formula (like 1.3
>>times total designed volume) for using say 1/2 oz sinkers and epoxy instead
>>of solid lead to generate the same poundage of ballast. This would be
>>wonderful for micro builders (there's plenty of space left in the keel area
>>for enlarging the casting) and others even with small amounts of lead. One
>>would think that after some actual testing was done the design community
>>might actually integrate this sort of casting (we'll call it "Cold Casting
>>Keels") into their various designs for homebuilders.
>>
>>
>>
>>
>>> -----Original Message-----
>>> From: Fries, John [mailto:John.Fries@...]
>>> Sent: January 26, 2000 2:36 PM
>>> To: 'bolger@egroups.com'
>>> Subject: [bolger] Re: modern Light Schooner
>>>
>>>
>>> I am considering the Single Handed Schooner; I'm not sure where
>>> that fits in
>>> chronologically with the Light Schooner. The design appears fast, and
>the
>>> discussion in Boats with an Open Mind implies that in practice it
>>> was a fast
>>> design. I have selected it because 1. it will fit in my garage,
>>> 2. looks a
>>> little less involved to build (not by much) than the Light
>>> Schooner, 3. it's
>>> very pretty and 4. I expect it to be very fast.
>>>
>>> > -----Original Message-----
>>> > From: Richard [SMTP:richard@...]
>>> > Sent: Wednesday, January 26, 2000 2:11 PM
>>> > To:bolger@egroups.com
>>> > Subject: [bolger] modern Light Scooner
>>> >
>>> > Someone here mentioned that the Light Scooner design was over 20 years
>>> > old.
>>> >
>>> > Does anyone know if PB&F have updated the design or designed a new
>>> > version since the original came out?
>>> >
>>> > The LS is supposed to be "faster than anything but a C class cat".
>>> > Anybody know of other PB&F designs in the same speed class?
>>> >
>>> >
>>> >
>>> >
>>>
>> ------------------------------------------------------------------------
>>> > For the fastest and easiest way to backup your files and,
>>> access them from
>>> > anywhere. Try @backup Free for 30 days. Click here for a
>>> chance to win a
>>> > digital camera.
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>>> > --http://www.egroups.com/cal?listname=bolger&m=1
>>> >
>>>
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>>>
>>
>>
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>>
>>
>
>
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>
>
Hi,
Just surfed some math sites and found that sphere packing (i.e.lead shot
packing) is a non-trivial problem that mathematicians are still wrestling
with!
There seems to be general agreement, though, that when spheres are packed
'grapefruit style' you get about 78% of the density of solid lead. In other
words, if you use lead shot in epoxy for ballast, add about 25% to the
volume to get the equivalent of solid lead (give or take . . .)
Bill
--bill.samson@...
Chebacco News can be viewed on:
http://members.xoom.com/billsamson
-----Original Message-----
From: Robert N. Lundy <robert@...>
To:bolger@egroups.com<bolger@egroups.com>
Date: 27 January 2000 00:15
Subject: [bolger] Re: modern Light Schooner
Just surfed some math sites and found that sphere packing (i.e.lead shot
packing) is a non-trivial problem that mathematicians are still wrestling
with!
There seems to be general agreement, though, that when spheres are packed
'grapefruit style' you get about 78% of the density of solid lead. In other
words, if you use lead shot in epoxy for ballast, add about 25% to the
volume to get the equivalent of solid lead (give or take . . .)
Bill
--bill.samson@...
Chebacco News can be viewed on:
http://members.xoom.com/billsamson
-----Original Message-----
From: Robert N. Lundy <robert@...>
To:bolger@egroups.com<bolger@egroups.com>
Date: 27 January 2000 00:15
Subject: [bolger] Re: modern Light Schooner
>I've spent quite a bit of time studying the single handed schooner in BWAOMsleep
>and wonder if it is really that much easier. I actually thought it looked
>somewhat more involved mainly for two reasons:
>
>1. The "removable" inboard rudder assembly looks straightforward in design,
>but tricky to execute. Also, it makes an extra trunk one has to build.
>
>2. The hundred pound centerboard gives me "keel anxiety" over dealing with
>that much lead.
>
>With that said, the two trickiest (to me anyway) parts of the building are
>also what gives this boat a special place-its self righting and the inboard
>rudder makes for a really elegant schooner look-not to mention you can
>inside of it.the
>
>Someone with some "I is an engineer" training needs to give some thought to
>the idea used by several folks to use epoxy and lead shot to cast really
>heavy items. Think about it. There should be some nice formula (like 1.3
>times total designed volume) for using say 1/2 oz sinkers and epoxy instead
>of solid lead to generate the same poundage of ballast. This would be
>wonderful for micro builders (there's plenty of space left in the keel area
>for enlarging the casting) and others even with small amounts of lead. One
>would think that after some actual testing was done the design community
>might actually integrate this sort of casting (we'll call it "Cold Casting
>Keels") into their various designs for homebuilders.
>
>
>
>
>> -----Original Message-----
>> From: Fries, John [mailto:John.Fries@...]
>> Sent: January 26, 2000 2:36 PM
>> To: 'bolger@egroups.com'
>> Subject: [bolger] Re: modern Light Schooner
>>
>>
>> I am considering the Single Handed Schooner; I'm not sure where
>> that fits in
>> chronologically with the Light Schooner. The design appears fast, and
>> discussion in Boats with an Open Mind implies that in practice it
>> was a fast
>> design. I have selected it because 1. it will fit in my garage,
>> 2. looks a
>> little less involved to build (not by much) than the Light
>> Schooner, 3. it's
>> very pretty and 4. I expect it to be very fast.
>>
>> > -----Original Message-----
>> > From: Richard [SMTP:richard@...]
>> > Sent: Wednesday, January 26, 2000 2:11 PM
>> > To:bolger@egroups.com
>> > Subject: [bolger] modern Light Scooner
>> >
>> > Someone here mentioned that the Light Scooner design was over 20 years
>> > old.
>> >
>> > Does anyone know if PB&F have updated the design or designed a new
>> > version since the original came out?
>> >
>> > The LS is supposed to be "faster than anything but a C class cat".
>> > Anybody know of other PB&F designs in the same speed class?
>> >
>> >
>> >
>> >
>>
> ------------------------------------------------------------------------
>> > For the fastest and easiest way to backup your files and,
>> access them from
>> > anywhere. Try @backup Free for 30 days. Click here for a
>> chance to win a
>> > digital camera.
>> >http://click.egroups.com/1/337/5/_/3457/_/948914198/
>> >
>> > -- Easily schedule meetings and events using the group calendar!
>> > --http://www.egroups.com/cal?listname=bolger&m=1
>> >
>>
>> ------------------------------------------------------------------------
>> BREAKTHROUGH ALTERNATIVE TO VIAGRA NOW AVAILABLE WITHOUT A PRESCRIPTION!
>>http://click.egroups.com/1/619/5/_/3457/_/948915411/
>>
>> -- Create a poll/survey for your group!
>> --http://www.egroups.com/vote?listname=bolger&m=1
>>
>>
>
>
>------------------------------------------------------------------------
>For the fastest and easiest way to backup your files and, access them from
>anywhere. Try @backup Free for 30 days. Click here for a chance to win a
>digital camera.
>http://click.egroups.com/1/337/5/_/3457/_/948932130/
>
>-- Check out your group's private Chat room
>--http://www.egroups.com/ChatPage?listName=bolger&m=1
>
>
>