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Re: [PSUBS-MAILIST] Brass vs. Bronze
While certainly possible, I think that there are a few practical
limitations to casting a submarine hull. The obvious one is size - you
need to cast the entire thing in one continuous pour, necessitating a
foundry with that melt capacity. The second is quality control -
porosity is much more difficult to avoid in casting than it is in weld
beads - once cast, every square inch of the hull would need to be
examined through non-destructive testing (x-ray, ultrasound, etc.), as
opposed to just weld seams, and then if you do find a problem, you may
have to scrap the whole thing and re-cast if it is not in an area that
is easily patchable. The third is dimensional control - save for the
ideal case where you cast a perfect cylinder with no hull penetrations,
bosses, stiffeners, etc., variable cooling rates due to material
distribution within the cast will cause the finished casting to deviate
from the original pattern. Ordinarily, foundries will account for this
by modifying the pattern to compensate (guesstimating), or by working
the finished castings in presses, etc. to bump them back into
compliance. For commonly cast parts like pump housings, etc., this is
no big deal, but pressure vessels are somewhat more dependent on their
geometry for proper function. This is not to say that it couldn't be
done, but my gut instinct is that it would be cost prohibitive, as well
as a lot of work.
-Sean
Akins wrote:
Hi Doug.
Your below post made me think of something. I wonder if anyone has
ever used a similiar molding process to cast an entire sub. Imagine if
someone used foam to create the hull thickness and any
exterior and interior parts they wanted casted along with the hull.
Then they could fill the interior with sand and coat the outside with
the same sand. Then the whole thing gets cooked underground
to allow the now molten foam to run out before the metal is poured in.
Then after the mold cooled you would have to remove the sand from the
subs hull interior.
I'm sure I have not stated this procedure technically correct, but you
get the idea. Like the discussions on concrete subs we've had here
before, this would allow hull penetrations, reinforcement rings, and
other things like hatch covers to be cast with, or next to the sub.
I've made a few underground sand ovens for cooking pigs in the ground
Hawaiian style and was
wondering if someone made a mold and then buried it underground so you
could heat it underground like the Hawaiian Umu sand oven, if this
idea is possible. One nice thing would be there would be no
weld joints to ever fail and you wouldn't take as much time in
construction and welding your sub, and you could have thicker portions
of hull material in different spots with ease. I wonder if a guy could
actually
dig up his backyard and build a small to moderate size 1 atm sub hull
this way. They used to cast cannons, which are a cylinder, why not a
sub hull? Just a concept idea I came up with.
An even easier idea might be to take a propane tank and encase it with
special concrete and make a concrete sub really cheaply compared to a
steel one. I like the whole molding, casting, pouring, your sub idea,
what a time and materials saver. Every day I look out back on my
acreage and see my two B52 wing tanks and think that if I don't wind
up making a pontoon boat out of them how interesting it would be to
encase them
in concrete and make them 1 atm two person subs.
Does anyone know of any information, web sites, etc that might explain
about making a mold out of sand and pouring your own metal sub as well
as info on concrete subs? I remember seeing someone here was building
a concrete sub.
Bill Akins.
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