The Process of Lost Wax Casting

Inject wax into a mold. I often create original one of a kind pieces as custom work, so if it's an original design that is carved from wax, the mold is not needed.

Step 1:

Remove bumps, lines, excess wax.   Clean up the waxes as much as possible.  The work that is done here will save you work later in cleaning up the metal after the casting process.  Trust me here.....more on those consequences later!

Step 2:

Attach a sprue so the metal will flow freely into each piece.  A main sprue is needed at the base for the metal to enter a piece.  These are attached in a tree formation.  All sprues connect to a main sprue base.  If things aren't sprued well, let's just say profanities will follow.

Step 3:

Dip the entire wax tree or piece into a debubblizer bath.  This will help keep the investment from forming little air bubbles on your pieces.  Air bubbles are a bad thing - remember the profanities?  You will make words up you never knew existed.

Step 4:

Put the flask over your sprued pieces.  If the flask does not fit tightly on the sprue base, use sticky wax to seal the sprue base and flask.  This will keep the investment from leaking out of the flask and again stop the inevitable swearing.

Step 5:

Investment is a plaster like material except it is refractive.  First it is mixed with water and vacuumed.  Then it is poured over the wax pieces and vacuumed again.  This gets out any residual air bubbles.  If you do end up with bubbles, they will make the cast piece look like it has chicken pox.  This would be the bad thing mentioned earlier.  You have about 7-8 mintes to work with the investment before it hardens.

Step 6:

Let the investment harden.  Put the flasks in the kiln and burn out the wax.  This process removes the wax image, but the imprint is left in the investment like a plaster mold.

Step 7:

The metal is put into a flask in the centrifuge for casting.  DO NOT over wind your centrifuge.  This could easily turn into a duck and cover, drop and roll, or learn to burn type of situation.  Molten metal being flung in a circular motion around the shop while you are screaming and running - bad. Metal going into your flask - good.  Third degree burns?  Bad.  Very bad.

Step 8:

When you have heated the metal to the melting point (1700-2000 degres F.), pluck the centrifuge arm so it will start to turn.  DO NOT leave your hand in there unless you really don't need the use of it for about six weeks.  I can't imagine that burns with a cast are comfortable.  Although, casts do come in fashionable colors now.

Step 9:

So, you have come out unscathed, no burns, wrist in tact, and you were smart to not touch the scalding flask with your bare hands. It has cooled to the point where you want to get rid of the investment.  It's time to immerse your still scalding flask in water so the thermal inertia can "blow out" the investment.  I must admit, it's kind of awesome.  If you don't do it before the investment totally cools, you will be chipping this stuff out for months to get to your piece.  (I personally have better things to do with my Friday night.)  On the flip side, do it too soon and your piece hasn't cooled enough which results in little pits and holes in the casting called "porosity". I think it was named by the Devil.  Ultimately it turns your expensive casting into an expensive paperweight..

Step 10:

Well done. You scrubbed the rest of the investment off under cold water. (If you don't use cold it will clog your pipes. Plumbers and spouses get a little angry when the pipes don't work.)  Now you have a shiny piece and they can go in an acid bath called the pickle, be cut apart, and made into a fabulous piece of jewelry.  You thought you were done.  Ha! Nice try. the fun's just starting.

Step 11:

Continue to Next Page: Clean Up

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