Dave has written to tell me that he uses a far different
process than the one I’ve described -- which was more oriented toward model
makers who cast a great deal in situ – such as Navis/Neptun. But we will
let Dave's word's tell the story:
“Something I forgot to mention, all our moulds are taken directly from
the master, it has proved to be so robust that there is no need to use
submasters, though I have 5 perfect castings set aside should I need them."
Using the master to make a mold is unusual, and may have something to
do with how the mold is formed in this case. The photographs show the basic
master Dave used, and the molds made from it. Dave tells us exactly
how he makes his molds for the Lion:
"This might surprise you, but the Lion is cast from a single mould which
ensures no join lines. I've not found the need to use a multiple mould
yet. The difficulty is removing the casting without damage, especially
with opposite facing undercuts from the upper pom-pom mounts and the deck
section the mast protrudes through. By filling from the bottom there is
no need to worry about any air escaping.”
“The hull, when cured, is mounted in a jig, aligned via the turret holes
and machined flat. Smaller models can be smoothed with sandpaper/wet and
dry. If I added more detail to the hull like the fwd funnel and bridge
section I would then have to use a multiple/split mould. I've attached
some photos of a mould and one showing the underside of a casting after
machining."
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