Pre-mix by hand 15-20 seconds then auto mix under vacuum at slow speed
60 seconds at 200-500 rpm or manually for 90 seconds. Gently vibrate investment
into ring just below the margins. With a sable brush paint the inside of the copings
carefully to avoid entrapping air bubbles then fill ring. Bench set for 60 minutes then
scrape glaze from the top of the ring (allows venting of gases).
Burn-Out:
Place ring at back of cold furnace, crucible in front. Raise temperature to 500藲F
(260藲C) and hold for 30 minutes (large rings - 45 minutes). Then raise temperature
to that suggested by alloy manufacturer.
Start Rate To Hold To Rate Hold
68藲F 22藲F/min 500藲F 30-45 min 1750藲F 23藲F/min 30-60 min
(20藲C) (12.2藲C) (260藲C) (954藲C) (12.8藲C)
1750藲 F
n
mi
藲F /
23
500藲F
n
mi
藲F/
22
68藲F
20 min 30-45 min 55 min 30-60 min
Crown & Bridge Auto Analysis Guide
Problem Cause Solution
Miscast- Ring not hot enough Raise temperature
(Short Casting) Check oven calibration
(Round Margins)
(Incomplete casting) Alloy not hot enough Check torch tip & fuel pressure
Pre-heat crucible in oven
Use casting flux
Insufficient alloy Increase amount of alloy used
Machine not wound enough Add more winds
Casting arm stopped Allow to stop on its own
Used solid plastic sprue Use hollow sprue or wax
Glaze not ground off ring top Eliminate glaze
Debris fell into sprue hole Keep sprue former face down
Casting spring weak Change spring
Holes throughout Casting Mold heated too high for alloy used Check alloy mfg temperature
Flash (Fins) Ring over heated Lower oven temperature
Investment over vibrated Vibrate enough to fill ring
Too much liquid to powder Reduce liquid amount
Invested ring in 2 parts Invest ring all at one time
Mold dropped Locate machine/ring closer
Bench set time too short Allow more time
Raised temperature too fast Check rate of climb
Mold split Make ring liner thicker
No ring liner used
Rough Casting Mold over heated Lower temperature/hold time
Wrong powder/liquid ratio Measure both powder/liquid
Investment over vibrated Vibrate enough to fill ring
Debubblizer left on wax Dry debubblizer on wax
Porosity Too much old alloy used Use maximum of 40% old
Over heated alloy Reduce melt time/cast sooner
Heat crucible with ring in oven
Use casting flux
Over heated ring Lower oven temperature
Loose Fit Wrong liquid/water ratio Increase water ratio
Tight Fit Wrong liquid/water ratio Increase concentrate ratio
Warped Casting Ring quenched in water Bench cool ring
Tension caused by sprues Use horizontal runner bar
WARNING
Contains respirable crystalline silica (RCS). Do not breathe
dust. May cause delayed lung injury (silicosis,
pneumoconiosis). The I.A.R.C. (International Agency for
Research on Cancer) reports (I.A.R.C. Monograph 68) there
is sufficient evidence in humans for the carcinogenicity of
inhaled crystalline silica in the forms of quartz or cristobalite
from occupational sources. The NTP (National Toxicology
Program) reports (Ninth annual report on Carcinogens) that
RCS is known to be a carcinogen based on sufficient
evidence from studies in humans indicating a causal
relationship between exposure to RCS and increased lung
cancer rates in workers exposed to crystalline silica dust.
Follow OSHA Safety and Heath Standards for crystalline
silica. See Material Safety Data Sheet (MSDS) for detailed
information.
NPCAHMIS CODE NOTE
Prolonged unprotected
Health 3
overexposure may result in
nonreversible
silicosis. Sufficient
evidence shows crystalline
silica causes cancer in
humans.
Non-flammable
Flammability 0
Non-reactive
Reactivity 0
Use NIOSH/MSHA/
Personal Protection
* OSHA approved
* respirator.
See Material Safety Data Sheet
DUST
(MSDS) for Detailed Information.
RESPIRATOR
庐
Manufacturer:
DENTSPLY International Inc.
DENTSPLY Austenal
York, PA 17405-0872
1-800-621-0381
www.austenal.dentsply.com
www.dentsply.com A1000-A Rev. C (5/07)