VMK Master

[Hal2a]

Just made the switch from Omega 900 to VM 13 to VMK Master. I would have continued to use Omega 900 but that was not an option (discontinued). So far I am happy with VMK Master exept for the window porcelain. I can't seem to get a clear glass effect, I have raised the temp. from 930 to 950, longer hold time and still a little milky. In the past with Omega and vm 13 this wasn't a problem. Does anyone have any experience with this problem?

 

[zvac]

Hal2a,

I am using Vm13. Why the switch to Vmk Master? Is it the difference in handling?
Just curious.

Thanks, Jack

 

[Bobby Orr ceramics]

Hal . What is your entry temp prior to vacuum and rate of climb kicks in? I start my high fusing porcelain @ 425C and low fusing porcelain @ 350C (eMax,symbio). Reason, you must get all the air from ceramic prior to initial "skin" forming on surface of ceramic. You will see better clarity in ceramic with lower entry temp than manufacturers suggest.........from the school of hard knocks.

, James

ps. you may be noticing the difference in clarity with Window and not a dentin since your eye is expecting the 'clear' look as opposed to dentins.

 

[artemis25]

I use VMK MASTER but i not like the color. e.g The color in 3L1.5 comes out as a dull green shade.
I have tried Increased the vakoum increase the temperature to no avail. So I gave up. Do you have a solution ?

I use Multimat furnace .

Thanks

 

[Hal2a]

Vm 13 has too much shrinkage and tearing for me. I will try entry at 425. I have been using an entry temp of 500. My furnace is a programat P500. I'll try a few things and keep you posted. Thanks for the input.

 

[charles007]

Hal, I also have the P500 oven.. Once you press start, the temp drops as you already know... I hate the fact the temp drops as the door closes then increases fast with the door closed... Is this good or bad using vita porcelain or others. Ivoclar told me the oven can be reset so that it holds the low temp in the drying stage...
Any opinions from old school techs Vita users........I love Vita porcelain, but it always pulls/lifts up at the margins...

Charles

 

[dmonwaxa]

Hal, I also have the P500 oven.. Once you press start, the temp drops as you already know... I hate the fact the temp drops as the door closes then increases fast with the door closed... Is this good or bad using vita porcelain or others. Ivoclar told me the oven can be reset so that it holds the low temp in the drying stage...
Any opinions from old school techs Vita users........I love Vita porcelain, but it always pulls/lifts up at the margins...

Charles

I'm not "olde school", those guys hang out in NC. I'm more " New Aged" he he. Seriously Charles I think you've hit the nail on the head. You need to reprogram so that the low temp is maintained during drying. Even then, some porcelains charts the recommended dry out temp is too high; Start at a lower dry temp and increase the dry time, probably 2-4 min depending on liquid used. I use VM 13 and dont have the issues youse guys talk about. At one time I even considered returning it based on the conversation here. I dont have the fancy ovens "NC oldetzheimerz" have, I use a WM pro 100 and an AutoPress Plus

 

[charles007]

I'm not "olde school", those guys hang out in NC. I'm more " New Aged" he he. Seriously Charles I think you've hit the nail on the head. You need to reprogram so that the low temp is maintained during drying. Even then, some porcelains charts the recommended dry out temp is too high; Start at a lower dry temp and increase the dry time, probably 2-4 min depending on liquid used. I use VM 13 and dont have the issues youse guys talk about. At one time I even considered returning it based on the conversation here. I dont have the fancy ovens "NC oldetzheimerz" have, I use a WM pro 100 and an AutoPress Plus

I'll call Ivoclar to make it hold the low temp. Kind of thought it had something to do with drying dsign porcelain, that has a tendency to tear, but only if you fire it ....
Any clues on the low temp and dry times using modeling liquids and water, with this clam shell. I've heard that this oven runs on the hot side, I've found it pretty much fires other porcelain very near recommended temps.
Lifting at the margins is another story.... Shofu Halo and MP very rarely lifts or tears, using water/line Trays.

 

[dmonwaxa]

I'll call Ivoclar to make it hold the low temp. Kind of thought it had something to do with drying dsign porcelain, that has a tendency to tear, but only if you fire it ....
Any clues on the low temp and dry times using modeling liquids and water, with this clam shell. I've heard that this oven runs on the hot side, I've found it pretty much fires other porcelain very near recommended temps.
Lifting at the margins is another story.... Shofu Halo and MP very rarely lifts or tears, using water/line Trays.

charles, since using dsign I have adopted the sprinkle technique for all the porcelain I use. My dry times are between 8-10 min, base temp starts around 400 - 500 depending on porcelain. I guess the lower temp and prolonged dry time allows for internal drying and heating which prevents surface crusting, which leads to tears and explosions, IMHO.

 

[Hal2a]

Charles, The start of the cycle was a problem for me as well. My Vita furnaces would keep a consistant hold time. When you fire VMK window porcelain, is it as clear as Omega 900? As for 3L1.5, this shade and any others are great straight out of the bottle.

 

[nabih]

Well charles I have been using vita since 1994 and used almost every vita product if you want to solve your problems with vm 13 you should keep your powder moist during working and do not dry your restoration with tissue paper before baking and stick to vita firing chart of course with respect to the temperature shift of you oven. Oh yeah one other tip that goes for all steps in opaque and build up powder. The first time your want to mix the powder use vita modeling liquid then if your mixture is dry and want to wet it use pure distilled water the vita modeling liquid contains ingredients that will make the color dull if they exceed certain amount

 

[Pieter]

Pre-dry temps are extremely important affecting both color and causing lifting especially when you like to pack wet.
Research by Dr. Michael Tholey indicates the following:
Lift position during drying is very important.
Keep to the ceramic manufacturers dry-hold temps.Ceramic transformation temp varies from brand to brand.Too much (temp) - crust formation with microscopic bubbles trapped in the ceramic affecting color and translucency. Too little temp with wet porcelain steam build up that lifts the margin. Liquid tends to follow gravity down to the margin area.
Lift position should be 2 min at lift position 100% open, 2 min at 50% open and very important 2 min at 25% open - then fire.Or the other way around lift at 0%, 50% and 75% closed.Dry big cases properly prior to firing with tissue.
Lifting at the margins - pack your ceramic a little drier.
Hope this helps