Bubbling in Vita VMK Master opaque! *PICTURES

[Mohammad Khair]

But if it's the carbide wouldn't all the days of opaque be bad? It's hard to tell techs who have used carbide for decades to switch haha. Also I have opaqued the ones that bubbled and still no dice.

Yeah ceramics ok and no vacuum error so maybe it's not vacuum

ceramics does not need a strong vacuum as the opaque, specially the paste opaque.
the pictures is showing a typical vacuum malfunction.
however, it could be any hose or valve.

 

[Mohammad Khair]

what is the vacuum read after 3 minutes of the vacuum start?

 

[rkm rdt]

The vacuum is working fine .

That's why the bubbles are coming to the surface.

The first pic would show white chalky porcelain if the vac wasn't working.

Try firing your buildup under a glaze cycle.

 

[edohwin]

I'll check the vacuum read tomorrow

It's a semi precious palladium based like 78 %.. so which burrs?

Yes, I think I will tell them to use the glass rod and not use water with brush. I think that has caused some problems

Nope paid salary or by hour but it's not usually an issue for the opaquers

Hmm not degassing is opposite to manufacturers procedures but maybe I should try a few

 

[charles007]

ceramics does not need a strong vacuum as the opaque, specially the paste opaque.
the pictures is showing a typical vacuum malfunction.
however, it could be any hose or valve.

Obviously we didn't go to the same lab school lol
Unless your using a very old oven ? ovens now beep, alarm, freeze up, whatever, to let you know the vacuum is not working properly..

I would bet my last dollar its one of these 3 things that caused the bubbling.
1. Incorrect oxy/propane setting.....
2. Incorrect finishing.. Only use white or pink stones, carbides with oil-less hand piece. I use pink stones and smooth off in same direction..
Carbides can cause problems if leaving rough finish, as stated above.
No matter what tools you use you want to leave a smooth finish on the frame and sandblast with clean air..
3. Improper opaquing techniques...
No water on brushes
Dry 8 to 9 minutes at 500c to 450c Fast drying will cause blistering .. Hot plate is not needed if you dry 8 to 9 minutes..
Option is to wait 1 minutes before pressing the start button and watch the fumes steam off the frames. May want to do this on larger cases or add 1 to 2 extra dry time.
Do not attempt to fire with 1 layer. Thick opaque and short dry time can cause bubbling.
fyi if you accidently close the door on your oven without drying, or use shorter dry time, you will get what your pictures show... lol

 

[Mohammad Khair]

The vacuum is working fine .

That's why the bubbles are coming to the surface.

The first pic would show white chalky porcelain if the vac wasn't working.

Try firing your buildup under a glaze cycle.

that is basically the pitfall that most of techs drop into, which is( the porcelain is fine = vacuum is 100% perfect )
the porcelain will be fine if the vacuum at 96% of its power, the paste opaque will not.

 

[rkm rdt]

You can't suck and blow at the same time.

 

[edohwin]

Got any specific recommendations on stones and carbide guys?

 

[Mohammad Khair]

Obviously we didn't got to the same lab school lol
Unless your using a very old oven ? ovens now beep, alarm, freeze up, whatever, to let you know the vacuum is not working properly..

I would bet my last dollar its one of these 3 things that caused the bubbling.
1. Incorrect oxy/propane setting.....
2. Incorrect finishing.. Only use white or pink stones, carbides with oil-less hand piece. I use pink stones and smooth off in same direction..
Carbides can cause problems if leaving rough finish, as stated above.
No matter what tools you use you want to leave a smooth finish on the frame and sandblast with clean air..
3. Improper opaquing techniques...
No water on brushes
Dry 8 to 9 minutes at 500c to 450c Fast drying will cause blistering .. Hot plate is not needed if you dry 8 to 9 minutes..
Option is to wait 1 minutes before pressing the start button and watch the fumes steam off the frames. May want to do this on larger cases or add 1 to 2 extra dry time.
Do not attempt to fire with 1 layer. Thick opaque and short dry time can cause bubbling.
fyi if you accidently close the door on your oven without drying, or use shorter dry time, you will get what your pictures show... lol

that is something you don't learn at school for sure,,, that is came along with white hair and a multi tens of thousands of porcelain crowns.
yes the new technology beep i agree.
and beep a lot i do agree also.

but it has been programmed to beep when major malfunction happens not a minor.
through years of use, the vacuum pump will have a lot of dirt inside,
open it and you will see, those liquid we use will cause this dirt, however the vacuum will not die but it will loose a typical function.
i can assure to you that most of the paste opaque is very sensitive to the vacuum and will disappoint you when the vacuum goes under 98% of its typical rate while the ceramic will not.

 

[rkm rdt]

Got any specific recommendations on stones and carbide guys?

It's been a while since I bought any. I'm sure any reputable supplier could help.

It's your process of elimination that will solve this. Don't try everything at once.

 

[sidesh0wb0b]

Carbides are good for high content gold alloys because they sheer the soft metal. Stones will create voids/rolls which trap air.

Stones are better on semi precious and base alloys.

Got any specific recommendations on stones and carbide guys?

i have my favorites. everyone will have different opinions on them though. I use "UM" burs (H138UM/H139UM and a few odds and ends others)

 

[KTR]

How are you applying the opaque? Brush it on and then use a glass rod or metal tool if you have to rub over the opaque and you will get a better adaptation. Set a 16 minute dry time going in the furnice. Set the low temp on furnace to 450c. Do not vibrate paste opaque.

 

[Mohammad Khair]

the guy make more guesses than what u provide him, its not his first time doing this job,

90% of the problems with casting technique will appear right on the funnel base of the cast

the use of the abrasive is mostly not a problem with hard metal alloys as you will sand blast it,
however, it will cause very little issue when mistakenly done to the high gold % or soft alloys.
usually it is save to use all kind of abrasives with hard metal alloys.

the fast pre-drying or the high entry temp will cause micro cracks on the opaque surface rather than air bubbles and it cannot be mistaken.( try it if u r not sure).

there still many reasons and problems to discuss here but apparently he is aware of most of it.
the problem is not common and last for months, only unusual hidden reason may cause it, which is i expect 80% is related to the vacuum issue as most of u not even aware of it yet.
however, the pictures is confirming that.

best wishes

 

[edohwin]

It's weird... some days it will be really bad like 10 or more copings are ruined and then another day maybe only 1 or 2 issues pop up then the following day none.

Maybe it is an inconsistent vacuum. I'll try opaquing with newer oven and better vacuum. Then see from there. Changing ovens seems like the easiest thing to do right now. Then I'll move onto the other things like burrs and casting technique etc.

 

[aqdental]

I'll check the vacuum read tomorrow

It's a semi precious palladium based like 78 %.. so which burrs?

Yes, I think I will tell them to use the glass rod and not use water with brush. I think that has caused some problems

Nope paid salary or by hour but it's not usually an issue for the opaquers

Hmm not degassing is opposite to manufacturers procedures but maybe I should try a few

High palladium alloy! Palladium absorb oxygen, so be very carefull not to have too much ox with your torch (listen the sound, flame should not be too noisy). Also try to darken the casting room, you get better idea of what your flame looks like. Bubbling means contamination. That can come from anywhere. Casting can be one couse.
Try to modify thinks 1 at the time. Don't put too many variables in your " search".
Good luck.

 

[Mohammad Khair]

It's weird... some days it will be really bad like 10 or more copings are ruined and then another day maybe only 1 or 2 issues pop up then the following day none.

Maybe it is an inconsistent vacuum. I'll try opaquing with newer oven and better vacuum. Then see from there. Changing ovens seems like the easiest thing to do right now. Then I'll move onto the other things like burrs and casting technique etc.

see it is the vacuum

why you have 10 in one day and then none on the next day can explain why the vacuum is the problem.

i will tell you a simple temporary solution.
open the muffle switch off the furnace and wait the furnace to cool down
clean with wet smooth tissue the O ring and the seat of the O ring(on the opposite side of the O ring where the O ring is going to seal when muffle is close) and dry with tissue
switch on the furnace
make your opaque and put it aside
run a firing cycle on the furnace and let the temp reach at least 1000*
hold for 5 minutes or more
when finish the firing cycle
bake your opaque directly after it, using normal firing program.

this is a temporary solution and will reduce 95% of your problems.

 

[edohwin]

I think it may be possibly the metal too cuz people are inconsistent with the flame right?

 

[Mohammad Khair]

you can solve it also by changing your opaque to a less sensitive one.
for example ceramco2 opaque with crystals is a criminal opaque and can withstand mostly any small problem like that one.
a friend of mine have use it with vita for more than ten years with no problem at what so ever level.

 

[Mohammad Khair]

I think it may be possibly the metal too cuz people are inconsistent with the flame right?

it could be, but not likely

the flame has 3 main parts
the very short cone light blue one where it will oxide the metal alloy
the normal blue with little orange or yellow about 5 to 10 cm long ... the good one for milting.
the end of the flame red orange or yellow which will carbonate (add co2 to the metal alloy if the alloy is reactive)
most of the technician did not miss that and will use the right distance for melting.

 

[greener1031]

http://postimg.org/gallery/1zk44dhqw/270c6e3d/


Getting inconsistent bubbling in different frameworks and copings

I'm using Argen Freedom Plus alloy with VMK master paste opaque and porcelain.

Can't figure out what it is, I'm doing everything the manufacturers are saying!

What could it be?

Thanks in advance, been battling this issue for months. Some good days, some bad days.

from pics it looks like metal contamination. All new metal. ( i know one tech uses real cheap NP, discards every button after casting once) clean torch tips, use new crucibles. I always used stones, check with stone manufacturer to be sure binder in stone is OK with NP, on NP and then sandblast with aluminum oxide. then throw in distilled water for a few minutes then dry and heat treat. Please remember distilled water is only clean the first time, if you reuse it is no longer distilled h20. Good luck this kind of stuff is very frustrating.