Black zirconia

[Dimis]

Hi guys does anyone knows why these happened? It's zirconia framework with czr layered on top on the6 anterior.everything went fine until the time I glazed. I glazed the raw zirconia with emax glaze and where I put emax glaze it turned black. I sandblasted the black places and I got the black color away because I thought it was the emax glaze,so I re glazed it with czr glaze and it came out milky white like it underbaked but it was glazed and shiny on the outside. Pls HELP

 

[CoolHandLuke]

i dont know how you managed it but this is amazing! you know how many rappers are going to want to work with you know? literally everyone

 

[Dimis]

i dont know how you managed it but this is amazing! you know how many rappers are going to want to work with you know? literally everyone

hahaha I hope I can find the way to redo it then if I want to make some money

 

[TheLabGuy]

If it's just the glaze that is black, assuming it is...lightly sandblast and clean appropriately, clean stain palette, and have another go at it. Probably had some contamination, usually the stain trays

 

[Patrick Coon]

View attachment 30930
Hi guys does anyone knows why these happened? It's zirconia framework with czr layered on top on the6 anterior.everything went fine until the time I glazed. I glazed the raw zirconia with emax glaze and where I put emax glaze it turned black. I sandblasted the black places and I got the black color away because I thought it was the emax glaze,so I re glazed it with czr glaze and it came out milky white like it underbaked but it was glazed and shiny on the outside. Pls HELP

Dimis,

This is caused by the organics in the glaze not fully burning out before the vacuum coming on. With these big bridges especially, you need to have a good drying time (at least 6minutes or more),a slow rate of rise (25-30C/min). you can also change the vacuum on temp from 450C to 480C and this will give a little more time for the organics to burn out before the vacuum starts.,

The areas where you sandblasted probably look more white and opaque, due to removing all the stain that had already been applied, or roughening the surface too much so the light is scattered too much.

 

[Dimis]

If it's just the glaze that is black, assuming it is...lightly sandblast and clean appropriately, clean stain palette, and have another go at it. Probably had some contamination, usually the stain trays

I changed th

Dimis,

This is caused by the organics in the glaze not fully burning out before the vacuum coming on. With these big bridges especially, you need to have a good drying time (at least 6minutes or more),a slow rate of rise (25-30C/min). you can also change the vacuum on temp from 450C to 480C and this will give a little more time for the organics to burn out before the vacuum starts.,

The areas where you sandblasted probably look more white and opaque, due to removing all the stain that had already been applied, or roughening the surface too much so the light is scattered too much.

is there any possibility that my furnace is contaminated?

 

[Dimis]

If it's just the glaze that is black, assuming it is...lightly sandblast and clean appropriately, clean stain palette, and have another go at it. Probably had some contamination, usually the stain trays

I changed the stain when I re did it and it didn't come black bad chalkie white

 

[TheLabGuy]

I changed the stain when I re did it and it didn't come black bad chalkie white

So you went from Black to White...now you sound like Michael Jackson, oh snap...I said that!!! You have some type of contamination going on, if you changed your glaze paste, stain pallete, cleaned bridge appropriately...I'd run your glaze oven up to 2000F and hold for 15mins to burn any contaminates in it (please don't put your bridge in it at this temp)...after it's cooled, then stain/glaze again and run bridge up under glaze cycle.