GC EUROPE Fujivest Super - Manual (Page 10)

10
GC New Casting Liner
Competitor product
The borders of the liner should be sealed with
a thin layer of petroleum jelly. GC New Casting
Liner is impervious to the absorption of liquid and
should not be immersed in or moistened with
water. If the border is not sealed, a wet liner used
or an absorbent dry liner there is a risk that the
powder/ liquid ratio of the mixture will be altered
and consequently alter the expansion.
Be sure that the entire inner surface of the metal
ring is evenly covered with casting liner and that the
liner is flush with the upper rim of the metal ring, so
that there is no direct contact between investment
and metal ring. A badly fitting ring liner leads to an
uneven expansion and the risk of crack formation.
We therefore recommend the use of GC New Casting
Liner, a dry casting liner made of ceramic fibers
For X3 ring size = Use 1 layer of
GC New Casting Liner
For X6 ring size = Use 2 layers of
GC New Casting Liner
For X9 ring size = Use 2 layers of
GC New Casting Liner
As a liner needs to provide an optimal buffer to
achieve accurate castings and reduce the risk of
cracking it is important that it is of the correct
thickness and does not absorb any water from
the investment. Liners that absorb water are
best avoided as they can remove moisture from
the investment mixture whilst setting, thus
compromising the final result by either causing
cracking or expansion in an unpredictable manner.
Conversely if the liner is soaked there is a similar
risk, but this time the problem is the dilution of
the investment mixture.
Dry GC New Casting Liner & Competitor product
Competitor product, GC New Casting Liner
liner absorbing water a dry casting liner
1.4.5 Wetting agents
A surface tension reducing agent is designed
to allow the investment to flow uniformly and
smoothly over all areas of the pattern helping to
eliminate casting bubbles; however please bear
in mind the following:
- All GC investment materials have the optimal
fluidity and smooth consistency which eliminates
the need for these agents.
- If these agents
are used, it is very
important to check
that they are fully dry
before pouring in the
investment material
as a wet residue of
these agents may
adversely react with the
investment material,
creating a rough
mould and casting
surface together with
an increased risk of
fracture.