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Sealing Rod
Page 5-1
Section Five:
Installing the Sealing Rod
Two types of sealing rods are used in the J-2
r
:
• a one-piece graphite rod
• a two-piece rod originally shipped
with J-2
r
machines (shown at right)
Neutec
™
recommends using the one-piece rod
but includes the instructions below for those
with an inventory of the two-piece rods.
The two-piece sealing rod consists of:
• a hollow ceramic rod
• a graphite sealing ball.
Replacing a Sealing Ball
Replace the ball at the first sign of wear to
prevent molten metal from leaking from the
pour hole. Sealing balls wear out faster than the
ceramic rods and can be replaced several times
before the rod will need to be replaced.
Whichever style sealing rod you use, be sure
that the rod can achieve a secure seal in the
bottom of the crucible. To check this, rotate
the sealing rod in the bottom of your crucible.
It will leave a graphite ring on the crucible.
You should be able to form a continuous ring of
contact. Liquid metal can escape from a very
small imperfection in this seal.
If you detect any imperfection in the ring,
replace the sealing ball.
1. Twist and gently pull the worn ball to
remove it. Use care not to break the rod
through using excessive force.
2. Gently sand, scrape, or file the old cement
from the sealing rod. Use care to avoid
reducing the diameter of the ceramic rod.
If this diameter is reduced, the new sealing
ball will not fit properly and will not align
correctly in the crucible.
3. Always check the ceramic rod by looking
through it before putting a new ball on. If
the hole is not perfectly straight, discard it.
4. Slide the new sealing ball on the sealing
rod to check the fit. The ball should slide
on easily. A small amount of play is normal.
Check the fit of the new sealing ball.
5. Mix a small amount of IZ-100 cement
(use a ratio of about 10 parts powder
to 1.6 parts water, by weight). Mix until
the cement is smooth and creamy.
6. Important! Wet the receiving end
of the sealing rod with water.
Wet the end of the sealing rod.
7. Apply mixed cement to the outside of the
sealing rod. Do not allow the cement to get
on the end of the rod or inside the hole.
