I’m at my wits’ end with my wax injector.
When I inject wax into molds of flat, smooth-surfaced objects, I get
weird streaky bubbles on the surfaces.
It almost appears as if the bubbles have been rolled or pushed as
the wax entered the mold, causing the streaks. Casting waxes with
these streaks produces castings with long shallow voids. Filling the
streaks with disclosing wax leaves marks on the castings. I have a
regular casting job that involves making a couple hundred flat
surfaced castings every few months. Every time I have to do one of
these jobs I waste several pounds of injection wax while trying to
get enough good waxes to fill the order.
I thought at first that maybe the wax pot had an air leak, allowing
air to get in as it was being injected.
I’ve gradually replaced every gasket and moving part on my
hand-pumped (note–no air compressor) Kerr Injectomatic II wax pot
that can be replaced, including finally replacing the entire nozzle
After the nozzle replacement, the streaky bubble problem
disappeared-- for a while. Now it’s back, worse than ever. I spent two
hours pulling waxes today and got ONE good wax.
I’m about ready to throw the danged wax pot away and buy a brand new
one, except that I can’t really afford to do that.
I keep the wax as close to the manufacturer’s stated melting point
as I can, and keep the pressure as low as possible. But I have tried
using hotter wax, cooler wax, higher pressure, pre-heating the mold
with a hair dryer, chilling the mold in the freezer, powdering the
mold with corn starch and various combinations of all of the above.
Nothing has helped. This happens with quite a few different molds, so
I’m certain that it’s not just the mold that’s causing the problem.
Any mold that’s fairly flat gets the streaky bubbles.
What could be causing this, and how can I fix it?
Feathered Gems Jewelry