I’ve enjoyed the discussion on PMC. Here’s another slant on it.
I’m sure some of you won’t agree with it, but that’s OK, if we
all liked the same things this world would be a dull place. There
are a few draw backs to PMC compared to casting however. Here’s a
few; along with some other ideas.
Because PMC shrinks up to 40+% when baked, the final dimensions
can’t be guaranteed.
If multiple pieces of the same design are to be made, the time
required to form each piece is almost as long as that required to
make a wax model.
No 2 pieces will be exactly the same size. Unless you’re making
things with a cookie cutter type tool.
Given the life expectancy of the tools required to make PMC or
cast, the per year or per unit cost of the additional equipment
required for casting is not that much greater.
The additional equipment needed depends on the quantity of items
you plan to cast (and whether you’re a tool junkie or not (bg)).
Depending on the mold scheme selected, (RTV or vulcanized rubber)
the mold making tools could be kept to under $100.00. The 2
additional biggest cost items a caster would probably want are a
vacuum unit and/or a centrifugal caster. Both of which are in
the $400.00 range, if new. However, if only a few pieces will be
cast, a much more economical route might be steam casting and a
home brew vibrator for vibrating bubbles from the investment.
If the cost of the additional equipment is spread out over about
an 8 year period, the additional tool cost is about 30 cents a
Again, depending on the number of pieces to be made, casting
could result in substantial time savings, which when factored
into the 30 cents per day cost would result in making things with
PMC actually costing more than casting.
To each his own. For my part, there aren’t enough hours in the
day to truly learn and master the skills that have served the
jeweler since the beginning of time. It’s sufficient to know
there’s a product with PMC’s capability that I could use if
needed, but to me its’ short comings far out way its’ benefits.