I am not sure what your problem is. If the lines are filled in and
the fill material is rouge on the surface the investment in the
engraved lines broke away. Think of the investment that fills in the
lines of a wax model as dams. The investment in the engraved lines is
very thin and susceptible to breaking if the flow of the metal is too
Most all of my work has many lines all engraved close together and
at least one mil deep. Every now and then a line will fill in. This
occurs usually where ever the molten metal flow hit’s a line which is
next to a sprue. At this point the metal flow is the strongest.
Sprues must be placed so that the metal flow is not directed against
the engraved lines.
I use a Foredom hammer tool tip grounded to an engraving edge
mounted in a Foredom hammer tool to cut the fill material out of the
original engraved lines. It may take several passes to re-cut the
line as deep as the original.
The investment that was in the engraved line will be floating in the
mold. That broken off investment may cause damage to the model some
where down stream of the break off point. The investment may be
embedded in the casting on show up as a depression on the surface of
I am not sure it does any good but I shake all my flasks with the
sprue end down before placing them on the vacuum pump. I hope that
any loose investment will shaken out.