Cracks Cracks N More Cracks

Kam Yu

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Hi Kam, you're probably fine as you didn't add any liquid to your zirconia. As far as I know, the risk is of steam expansion in the zirconia, from the liquids, being released too fast. JMHO

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Actually, we are using liquids now. Still havent had any cracks. Think we had a small half moon on the margin once. But i think 250 is a better temp. Id rather go 250 with a longer dry time.
 
Sda36

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Good stuff [emoji4] As I mentioned earlier in this thread a $7.00 investment in a coffee cup warmer is a gift. Controlled and consistent and fits your dish perfectly[emoji4]

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sidesh0wb0b

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Good stuff [emoji4] As I mentioned earlier in this thread a $7.00 investment in a coffee cup warmer is a gift. Controlled and consistent and fits your dish perfectly[emoji4]

Sent from my LG-H812 using Tapatalk
also keeps the coffee warm :D
 
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Its amazing how small and seemingly insignificant an impact can cause on raw Zr. Always lay a towel or something down under your work when cutting out crowns. Drop one just a couple inches on to a hard surface and you can cause cracks that wont show up until after sintering.

If youre getting results no one else is, youre doing something no one else is.
 
JMN

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Its amazing how small and seemingly insignificant an impact can cause on raw Zr. Always lay a towel or something down under your work when cutting out crowns. Drop one just a couple inches on to a hard surface and you can cause cracks that wont show up until after sintering.

If youre getting results no one else is, youre doing something no one else is.
<Yoda>Mmm. Very two edged, it is.</Yoda>
 
JVitto

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Sorry I haven't been back on in a bit to answer/thank you guys, a few days after I posted this my thermalcoupler went out...ERR4 on the sintering oven n it being my only sintering oven u can imagine what happened... I'm not a big lab but I do sinter 20-25 units a day n dont have time to miss one day let alone 3. Anyways I lowered the toaster down to 250. It seemed to do the trick but also remember the the thremalcouple did go out a day or two later I'm not sure if the temps in the oven were running correctly but I have now done everything said.... I'm more careful in green state, lowered toaster, and change beads. I did try sideshowbob's program n they didn't come out as nice as usual probably diff ovens so I stuck with my programs and they are looking great. Thank you everyone!!!!!
 
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Sorry I haven't been back on in a bit to answer/thank you guys, a few days after I posted this my thermalcoupler went out...ERR4 on the sintering oven n it being my only sintering oven u can imagine what happened... I'm not a big lab but I do sinter 20-25 units a day n dont have time to miss one day let alone 3. Anyways I lowered the toaster down to 250. It seemed to do the trick but also remember the the thremalcouple did go out a day or two later I'm not sure if the temps in the oven were running correctly but I have now done everything said.... I'm more careful in green state, lowered toaster, and change beads. I did try sideshowbob's program n they didn't come out as nice as usual probably diff ovens so I stuck with my programs and they are looking great. Thank you everyone!!!!!
20-25 units a day, and you gamble with ONE sinter oven?
 
JVitto

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20-25 units a day, and you gamble with ONE sinter oven?
Yea why? Is that to much for one? I have looked into other or a back up but 10grand isn't cheap.. where I'm at I'm NOT getting good money for a full contour zirconia. I'm gonna buy a back up but man I'm doing my best....profit margins around here are not really that great
 
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Yea why? Is that to much for one? I have looked into other or a back up but 10grand isn't cheap.. where I'm at I'm NOT getting good money for a full contour zirconia. I'm gonna buy a back up but man I'm doing my best....profit margins around here are not really that great
If its how you earn a living, then a back up isn't a luxury. I couldn't sleep like that. Even at the lower end of your numbers, go with 20 units. X 5 days a week, even at Glidewell discount prices that's over half a million a year.

Things break.
 
JVitto

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I see what ur saying I've only been milling n sintering for 8 months so it's really new to me man, ok a back is needed.. oh corse that was already in my nugget just spending the moneys n not having that cash in the bank ,Just In Case was my train of thought.. I think I just needed to hear that.. if that makes sense... there not a a lot labs here so the ones I get to talk to are on a completely different platform either their way smaller or completely larger honestly I probably need to look into back up sintering oven n having another mill and another scanner especially if I plan on printing models basically that's the next step and a few doctors want to send Trios scans so I need to start putting some models because they don't want to go to model less yet. You know when you're just trying to make sure there's gonna be food and everybody's table and you gonna make it through the next 10 years it's a bit stressful right now .....we're sintering in 20 to 25 but what's going to happen next month or the month after ...or six months from now.. probably nothing will change but that's the worrywart in me thanks for the info man
 
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I see what ur saying I've only been milling n sintering for 8 months so it's really new to me man, ok a back is needed.. oh corse that was already in my nugget just spending the moneys n not having that cash in the bank ,Just In Case was my train of thought.. I think I just needed to hear that.. if that makes sense... there not a a lot labs here so the ones I get to talk to are on a completely different platform either their way smaller or completely larger honestly I probably need to look into back up sintering oven n having another mill and another scanner especially if I plan on printing models basically that's the next step and a few doctors want to send Trios scans so I need to start putting some models because they don't want to go to model less yet. You know when you're just trying to make sure there's gonna be food and everybody's table and you gonna make it through the next 10 years it's a bit stressful right now .....we're sintering in 20 to 25 but what's going to happen next month or the month after ...or six months from now.. probably nothing will change but that's the worrywart in me thanks for the info man
I hear you. I see the little girl youre holding in your avatar...that's worth worrying about. At least have extra heating elements and a thermocouple on hand. Best of luck...and visit here more often!
 
Kam Yu

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If you need help or advice with building ur lab, people here are willing to give good advice for that. This network is a huge blessing. Alot of people here really care. If u mind me asking, where do u live?
 
JVitto

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If you need help or advice with building ur lab, people here are willing to give good advice for that. This network is a huge blessing. Alot of people here really care. If u mind me asking, where do u live?

central Florida
 
JVitto

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I hear you. I see the little girl youre holding in your avatar...that's worth worrying about. At least have extra heating elements and a thermocouple on hand. Best of luck...and visit here more often!

I Will be hanging around here a lot more, Thank You for the help!!!
 
sidesh0wb0b

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Sorry I haven't been back on in a bit to answer/thank you guys, a few days after I posted this my thermalcoupler went out...ERR4 on the sintering oven n it being my only sintering oven u can imagine what happened... I'm not a big lab but I do sinter 20-25 units a day n dont have time to miss one day let alone 3. Anyways I lowered the toaster down to 250. It seemed to do the trick but also remember the the thremalcouple did go out a day or two later I'm not sure if the temps in the oven were running correctly but I have now done everything said.... I'm more careful in green state, lowered toaster, and change beads. I did try sideshowbob's program n they didn't come out as nice as usual probably diff ovens so I stuck with my programs and they are looking great. Thank you everyone!!!!!
glad youve gotten things figured out!
 
prosthotech

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Sounds like the cooling rate is too high. Possible issues we've noticed over the years, especially when large/full arch frames are involved:

1) Insufficient drying times for larger structures (unlikely)
2) Heat rate too fast for larger structures / number of structures (likely)
3) Hold time insufficient for larger structures / number of structures (likely)
4) Cool rate too fast for larger structures / number of structures (very likely)
5) Stain and glaze cycle needs to be lengthened for both heat rate and cool rate (very likely)
6) Porcelain layering cycles also need to be adjusted for heat and cool rates, and longer hold time
7) Large structures also require a stabilizer to minimize warping.

Hey Everyone, so ive read through a bunch of threads on cracks in your zirconia after sintering. After reading honestly I think Im more in the dark than before. Ive read it can be my milling machine, sintering beads, oven calibration, drying time and manner, ETC....... We have been milling for over a year with only minor issues. 2 days ago i had a #8 on a 8-9 splint crack right where the spruee was then a singe full contour crack on a cusp now this morning I had a 8-11 framework crack where the connector met the coping. We have a Roland DWX-51D, Brand New Burs, No Recent Power Outtages or Errors. We have a WhipMix Infinity ZR oven 6 months old. I use a toaster oven to dry 300 degrees for 20 min. We use Whipmix Vericore Zirconia. Any Ideas??? My beads are 7 months old and im using ZirkonZahn Colour Liquid Prettau Aquarell Please help..
 

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