Furnace issue between porcelain brand

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Aditia KT

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20210304_153237.jpg 20210315_134257.jpg
Guys, i have furnace from dentsply multimat cube
I use dentsply and shofu porcelain brand
When use dentsply porcelain (ceramco, celtra ceram) everything works perfectly with their firing chart
But on the next day i fire the shofu porcelain (following the shofu firing chart for sure 760-770) and as you can see the result is first image, i have tried at 760, 770 780 and still raw
And today i fire it ad 810-820 (about 40-50 degree above the chart, yes i break the rule with my instinct) and the result is on the 2nd picture
Somebody said i have to calibrate my furnace, but how can the furnace loosing 40-50 degrees in only 1 day ???
What are you thinking guys about this case ?
FYI : celtra ceram and shofu vintage LD have similar firing chart
 
CatamountRob

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I think you should start by calibrating your furnace, then get back to us.
 
Car 54

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After you run a calibration, fire a T-Glass tab until it fires correctly, clearly.
Make sure you have vacuum going for the Shofu program, and that you're holding it for 1mn.

shofu.jpg
 
Car 54

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What do you mean T-glass tab ?

It may not have come with the kit you bought. It's a clear porcelain that Shofu sells.
It's nice to have around, for times like this. Otherwise, fire a T tab. You can make a form using putty and
a vita shade tab, or freehand with a spatula some porcelain using build up liquid for plasticity,
or a shade tab instrument like SmIle Line carries. Elevate, fire it on platinum foil, not directly on "gauze" material.

tglass.jpg
 
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Contraluz

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View attachment 38123 View attachment 38124
Guys, i have furnace from dentsply multimat cube
I use dentsply and shofu porcelain brand
When use dentsply porcelain (ceramco, celtra ceram) everything works perfectly with their firing chart
But on the next day i fire the shofu porcelain (following the shofu firing chart for sure 760-770) and as you can see the result is first image, i have tried at 760, 770 780 and still raw
And today i fire it ad 810-820 (about 40-50 degree above the chart, yes i break the rule with my instinct) and the result is on the 2nd picture
Somebody said i have to calibrate my furnace, but how can the furnace loosing 40-50 degrees in only 1 day ???
What are you thinking guys about this case ?
FYI : celtra ceram and shofu vintage LD have similar firing chart
Question: Are you firing everything on that fibre glass pad? If I remember correctly, these absorb quite a bit of heat. Maybe try a different tray?
 
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Aditia KT

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Why T glass ?
Anyway im considering to buy trabslucent effect, if i have to choose one, which one i need to buy, T or T-glass ?
 
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Aditia KT

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Question: Are you firing everything on that fibre glass pad? If I remember correctly, these absorb quite a bit of heat. Maybe try a different tray?
Yes im using fibre pad, this is veneer, i cannot hang it, or maybe can i put it on honeycomb directly ?
 
Car 54

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Why T glass ?
Anyway im considering to buy trabslucent effect, if i have to choose one, which one i need to buy, T or T-glass ?

You'll use opal translucent OT more often. T-Glass will last you a lifetime. T Glass will show up clear when correctly fired, it will tell you if you're firing the porcelain to its proper firing, maturity temp. Granted, things can get overfired. That's why you start off with the manufactures recommendations and go from there. But you can also fire up a A2 tab, look for the egg shell sheen and compare it to the guide. Shofu is good company as far as matching shades to the Vita guide.

Try a honey comb tray like Contraluz mentioned, that's a good idea. I tend to fire my veneers on a honey comb tray, on platinum foil, to get them elevated and suspended in the heat.

20210315_110950.jpg

edit: to clarify Opal Translucent, and not standard Translucent.
 
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Contraluz

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Yes im using fibre pad, this is veneer, i cannot hang it, or maybe can i put it on honeycomb directly ?
These are pressed and layered veneers, correct? You should be able to put them directly on the tray.

However, I use Peg putty to 'hang' them on a wire peg, to get the best firing possible. This may actually resolve the under-firing. Certain honey comb trays and these fiberglass pads can make a difference up to 10-15 celsius, which will underwire your dentin/enamel porcelain.
 
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Aditia KT

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These are pressed and layered veneers, correct? You should be able to put them directly on the tray.

However, I use Peg putty to 'hang' them on a wire peg, to get the best firing possible. This may actually resolve the under-firing. Certain honey comb trays and these fiberglass pads can make a difference up to 10-15 celsius, which will underwire your dentin/enamel porcelain.
You'll use translucent T more often. T-Glass will last you a lifetime. T Glass will show up clear when correctly fired, it will tell you if you're firing the porcelain to its proper firing, maturity temp. Granted, things can get overfired. That's why you start off with the manufactures recommendations and go from there. But you can also fire up a A2 tab, look for the egg shell sheen and compare it to the guide. Shofu is good company as far as matching shades to the Vita guide.

Try a honey comb tray like Contraluz mentioned, that's a good idea. I tend to fire my veneers on a honey comb tray, on platinum foil, to get them elevated and suspended in the heat.

View attachment 38128

Sir, i already calibrate my furnace, but nothing wrong with the furnace... but i still have to increase 50 degrees from shofu instruction (from 770 to 820) if i fire it below the 810, the porcelain always unwell fired
 
Car 54

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It's been a long time since I've done a porcelain furnace calibration, but shouldn't the silver just hit the balling up point when it hits its calibration temp?
It looks like yours has a slight sweat to it, or is it a silver coated wire? Please, correct me (anybody) if I'm wrong...I won't cry :)
 
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Sir, i already calibrate my furnace, but nothing wrong with the furnace... but i still have to increase 50 degrees from shofu instruction (from 770 to 820) if i fire it below the 810, the porcelain always unwell fired
Don't know what furnace your using but that's not the way to calibrate any oven ! get your furnace manual out.
In your picture you have taken out the tray and the long silver pole..... crazy Banghead
 
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Car 54

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@Aditia KT I did edit my post to suggest that if you're going to get a translucent modifier, get the OT (not the T) Opal Translucent.

When I posted it was a bit off the cusp as far as T. Shofu Translucent can tend to create a bit of a low value if you use to much of it, as it's along the line of traditional translucent, like what they came out with in the original line of porcelain. Opal Translucent would be a better option as its light scattering properties of opalescence will help with the "gray" low value issue, but still needs to be used carefully.

Even though this is from the Halo guide, it still applies to the LD porcelain. (just in case you didn't have this information).

20210317_092148.jpg

20210317_092254.jpg

20210317_092325.jpg
 
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Aditia KT

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It's been a long time since I've done a porcelain furnace calibration, but shouldn't the silver just hit the balling up point when it hits its calibration temp?
It looks like yours has a slight sweat to it, or is it a silver coated wire? Please, correct me (anybody) if I'm wrong...I won't cry
 

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Aditia KT

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@Aditia KT I did edit my post to suggest that if you're going to get a translucent modifier, get the OT (not the T) Opal Translucent.

When I posted it was a bit off the cusp as far as T. Shofu Translucent can tend to create a bit of a low value if you use to much of it, as it's along the line of traditional translucent, like what they came out with in the original line of porcelain. Opal Translucent would be a better option as its light scattering properties of opalescence will help with the "gray" low value issue, but still needs to be used carefully.

Even though this is from the Halo guide, it still applies to the LD porcelain. (just in case you didn't have this information).

View attachment 38142

View attachment 38143

View attachment 38144
Sir, i dont have these, where can i get this description ?
If you dont mind can you email to me ?
 
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Aditia KT

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@Aditia KT I did edit my post to suggest that if you're going to get a translucent modifier, get the OT (not the T) Opal Translucent.

When I posted it was a bit off the cusp as far as T. Shofu Translucent can tend to create a bit of a low value if you use to much of it, as it's along the line of traditional translucent, like what they came out with in the original line of porcelain. Opal Translucent would be a better option as its light scattering properties of opalescence will help with the "gray" low value issue, but still needs to be used carefully.

Even though this is from the Halo guide, it still applies to the LD porcelain. (just in case you didn't have this information).

View attachment 38142

View attachment 38143

View attachment 38144
Sir, i dont have these, where can i get this description ?
If you dont mind can you send to my email ? [email protected]
 
Car 54

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Sir, i dont have these, where can i get this description ?
If you dont mind can you email to me ?

It's from the old Halo manual. Can you just right click on the above images, hit save image as, then print them for your reference?
The links to the right side of the Halo page have some of the information, otherwise it's just going to be another screenshot you would have to save and print from. Just looking out for you, but maybe edit your email from your above post, just so a non member doesn't spam you? You can PM me, if desired.

 
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