Duceram kiss porosity problem

[Delijasanov]

Hello
Im having the porosity problem 2 gays ago.I was working on the bridge as usual an on glaze i noticed very small porositys little dots.I didnt change setings on furnace and i cheked vacum lev is good temp is good dont know what causes the problem
Its ivoclar p300 oven. Did someone have had some problem like that?

 

[kcdt]

Hello
Im having the porosity problem 2 gays ago.I was working on the bridge as usual an on glaze i noticed very small porositys little dots.I didnt change setings on furnace and i cheked vacum lev is good temp is good dont know what causes the problem
Its ivoclar p300 oven. Did someone have had some problem like that?

Why are running vacuum at glaze?

 

[Delijasanov]

Why are running vacuum at glaze?

My bad,i didnt explain correct.
I get porositys at first and second fiering,they are bearly noticable but i have them. Its weard that i finished one bridge and was perfect like all others. After that one same programs,same ceramic,same day porositys started to came up on all units

 

[2thm8kr]

My bad,i didnt explain correct.
I get porositys at first and second fiering,they are bearly noticable but i have them. Its weard that i finished one bridge and was perfect like all others. After that one same programs,same ceramic,same day porositys started to came up on all units

How many times has the alloy been recast?

 

[rkm rdt]

Im having the porosity problem 2 gays ago.

Have you tried chocolates and flowers?

 

[Delijasanov]

How many times has the alloy been recast?

I think i casted with 100 new alloy (sometimes i mix it with small amount of old). U think metal can cause that problem ?

 

[sndmn2]

Porosity on the surface sounds like a moister control problem to me. That being said several years ago I started getting porosity and started chasing my tail to figure it out.. It turned out to be an over frosted muffle .. $600 for a new muffle and all was well.

 

[H.Ross]

Faced it with Vita, changed the furnace due to vacuum issue and problem got solved.. few days ago and by mistake I was staining a crown and glazing it at the same time, water got mixed with glaze and got not very deep pours

 

[Pieter]

It could be metal contamination or your sandblasting sand could be contaminated. I would change both for new and see how it goes. I mix 25% new metal with any old metal. Had a technician sandblasting his acrylic dentures in my sandblaster for metal. Endless problems until I discovered what he was doing. Good luck - sometimes not easy to solve

 

[dimtsic]

Porosity is difficult to pinpoint it could be a number of things as mentionned previously, moisture control, sand in sandblaster etc.
Try grinding your restoration and see where the porosity starts is it from alloy or after opaque then you will have an idea if its maybee an alloy contamination problem or opaque porcelain issue. check the following:
Porcelain and opaque drying time
Wet dry porcelain application
Opaque thickness
Is your air supply full of moisture contaminating air with which you sandblast? Is your torch clean with no carbon deposits? Check oxydization process making sure framework is clean, if your oven muffle is clean.Try changing to new finishing burs.

I remember once a long time ago we had a similar problem i changed everything thank God now we are 95% zr good luck