[TML] Molding Ships

[Jerry W Barrington]

On 9/10/07 8:31 PM, "Richard Aiken" wrote:

> On 9/9/07, Garry Ward <garry.e.ward at worldnet.att.net> wrote:
>> Take asteriod, core out a section that matches the outer profile of the
>> ship.
>> 
>> Take the removed core and carve it to match the interior hull surface (no
>> rooms or corridors, just the interior surface of the hull).
> 
> Postulate: You are using nickel-iron asteroidal material, since it has
> to stand up to the heat of the molten steel without cracking or
> deforming.

Ouch!  I just thought of something: shrinkage.  Molten steel has a higher
volume than cold steel.  So, after casting, it shrinks.  In a small mold
this isn't too much trouble, especially the more common solid mold.  But
over a 100m or more hull, that steel is gonna shrink a lot and squeeze the
inner part of the mold.  This shrink is typically 1 to 6 %, so a 100m mold
will shrink 1 to 6m.



On 9/13/07 11:50 PM, Kirk Bailey wrote:

> <snipped description of inflating an asteroid>
>
> Not exactly blowing it in a mold, but in the right astrophysics world near
> a good industrial center, it's a way  to make some nice non buffered hulls
> of considerable size.

That was discussed back in the 70's.  I know Niven & Pournelle wrote about
it (using mirrors as Leonard mentioned), don't know if they were the first.
Problem is, there's no way to heat it perfectly uniformly, nor is it uniform
to start with.  So it won't just blow up like a balloon.  More likely to
blow one side out.