Burnout is the hidden backbone of clean castings, strong surface detail, and dependable fill. A well planned schedule removes wax, dries the mold, drives off water, and conditions the investment so it can face metal without cracking. In this guide on Top 10 Burnout Schedules for Jewellery Casting Flasks, you will find practical, step by step patterns that match wax types, flask sizes, and metal choices. Each schedule states ramp directions and key soaks, with reasons that help you adjust safely in your own shop. Follow the logic, watch color, smell, and kiln readouts, and record results. Small, steady changes bring repeatable quality.
#1 Standard gypsum schedule for small to medium flasks
Start at room temperature. Vent the kiln. Climb to 150 C and hold for one hour to melt and drain wax while drying the mold. Continue to 350 C and hold for ninety minutes to clear water and begin binder burnout. Raise to 730 C and soak for two hours to finish carbon removal and fully cure the investment. Lower to your casting temperature, often 500 C for sterling and 450 C for yellow gold. Pour when the flask core has equalized. Use witness flasks to confirm that heat has reached the center.
#2 Overnight energy saver for high yield consistency
Load late in the day. Set a slow ramp to 120 C and hold for two hours to prevent boil out and avoid steam cracks. Climb at one to two degrees per minute to 350 C and hold for three hours so large trees dry fully. Advance to 700 C and soak for three hours. Program an automatic drop to 480 C for silver or 430 C for gold by morning. This gentle profile reduces thermal shock, improves surface quality, and frees staff time. Record power use. Many shops report lower scrap with this schedule.
#3 Fast turnaround for rush jobs with small flasks
Use only on solid wax patterns and fresh investment. Start at 150 C for forty five minutes with vents open. Increase to 400 C and hold one hour to push off water. Raise to 760 C and soak for ninety minutes, watching for smoke end and a clean kiln atmosphere. Drop to 520 C for silver or 470 C for gold and cast within fifteen minutes. This cycle trades deep curing time for speed, so avoid large or stone set builds. Check for ash; if present, add thirty minutes at peak on the next run.
#4 Stone in place low temperature schedule
Select stones and solder safe for casting in place. Begin with a long dry at 120 C for three hours so moisture leaves slowly. Climb to 300 C and hold three hours to finish dewaxing without swelling the investment around settings. Advance to 480 C and soak for four hours, which completes most binder burnout while protecting stones that tolerate moderate heat. Stabilize at a casting hold near 430 C and pour gently to limit thermal shock. Expect slightly richer texture inside sprues. Document stone types and do trials before any production release.
#5 Phosphate bonded schedule for platinum and palladium
Use phosphate investment and steel flasks or strong sleeves. Dry at 150 C for ninety minutes with vents open. Ramp to 400 C and hold two hours to remove free water and wax residues. Increase to 900 C to 950 C and soak for three to four hours depending on flask mass, ensuring complete carbon removal. Lower to 650 C to 700 C for platinum or 600 C to 650 C for palladium just before the pour. Maintain good airflow and avoid sulfur sources. Record color of exhaust and adjust holds if any soot remains.
#6 Resin printed pattern burnout with ash control
Print in a castable resin rated for low ash. Overnight cure per maker guidance. Start at 90 C for one hour, then 135 C for another hour to drive off monomers without foaming. Raise to 200 C and hold ninety minutes, then to 300 C for two hours to complete de bind and drain. Advance to 760 C and soak three hours with good airflow. If ash spots appear, add a 30 minute oxygen step at 820 C. Finish by dropping to your casting temperature. Use extra vents; resin needs more paths than wax.
#7 Heavy flasks and dense trees extended soak
Large cross sections heat slowly. Prevent thermal gradients by holding longer at key stages. Dry at 150 C for two hours, then rise to 350 C for four hours so the core loses bound water. Increase to 730 C and soak for four to five hours. Use a sacrificial witness flask with a center thermocouple to confirm the core reaches target before you time the soak. Lower to casting temperature and hold at least forty minutes. This approach cuts incomplete burnout, flashing, and fins that form when the surface overheats while the center stays cool.
#8 Steam dewax hybrid for cleaner kilns
Remove bulk wax in a steam dewaxer at about 95 C for thirty to forty minutes. This reduces smoke load and improves dimensional stability. Move flasks to a preheated kiln at 150 C for one hour to finish drying slowly. Climb to 350 C and hold for two hours, then to 730 C for two hours with vents open. Drop to the casting temperature and pour. Because most wax left the mold as a liquid, you will see less residue on shelves and fewer trapped bubbles. Steam dewax also helps delicate prongs keep their shape.
#9 Dehydration focused schedule for humid days
Moist air slows drying and can cause steam spall. Start with the kiln at 100 C and hold flasks for two hours with plenty of ventilation. Raise to 150 C for two more hours, then step to 250 C and hold ninety minutes. Climb to 350 C and soak two hours to complete free water removal. Advance to 700 C and hold two to three hours, watching for clear exhaust. Lower to the chosen casting temperature. This gentle early section avoids pressure spikes inside the mold that can open seams and create fins on tight filigree features.
#10 Carbon cleanup recovery after sooty castings
When surfaces show dull gray or black acne, run a corrective cycle. Begin at 150 C for one hour, then 350 C for two hours. Increase to 800 C and soak for four hours with vents fully open to promote oxidation. Add a targeted 30 minute 850 C step if you still smell burnt binder. Let the kiln clear for ten minutes, then drop to the standard casting temperature and pour a test ring tree. Inspect under magnification. If surfaces brighten and detail improves, adopt a longer high hold in your regular schedule.