Lost foam casting is COOL!
Until you do it, you don't quite beleive it will work, but it does.
In it's simplest form, the foam is shaped as desired (including a
sprue), placed in firmly packed dry, loose sand, and poured with molten
metal. The hot metal vaporizes the foam and hardens before the sand has
a chance to move. The resulting casting (if done correctly) is a
faithful reproduction of the foam pattern right down to any bead
structure and fingerprints left in the glue.
Of course there are variations and details not yet explained, but you
get the idea.
Some advantages of Lost Foam Casting are
You can quickly throw together a simple pattern
or just use a piece
of scrap foam to pour an ingot or to make a billet to be machined.
- relative ease of obtaining the
Some disadvantages are
- one use patterns
- smoke (And FIRE)
When you pour the metal in a lost foam
mold, there will be a great plume of hot smoke and noxious gases that
will probably light on fire. Do NOT bend over the mold as you pour!
Make every effort not to breath these fumes. A small fan blowing from
your back across the mold will help a lot.
Here is a short video from
Dave Drecher showing the
smoke and flame :
yet to be covered:
Embedding the foam in the sand
Pouring the mold