Hi, Noel. Great question. And the only real answer is, if you end up
with an investment inclusion than it was too big. Let’s get into
more detail though, and look at why an internal bubble is a problem.
The biggest potential problem with an internal bubble is that when
the wax is covered in investment, and then vacuumed, the vacuum will
cause the bubble to pop and the investment will go into the void
left by the bubble. So the real issue is when the bubble is close in
proximity to the surface of the wax. This creates more potential for
the bubble to pop and investment to enter. A bubble that is deeper
inside a medium to thick part, may not be too much of an issue.
Ifthe bubble pops, it could just have a very small pin hole letting
the air out. This tiny hole could inhibit any investment from
entering. But there is no real method for knowing when there will be
a problem and when there won’t be. The best suggestion is to
eliminate any air bubbles and not to worry about it.