Help, new to pressing

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Drews Dental Lab

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I am new to pressing and I am having an issue with fit and the texture, along with some complete failures.

I am using Microstar investment 20ml expansion liquid to 5ml distilled water with emax and Gc Lisi with same results

I have tried my burn out oven diffrent temps ranging from 1500 to 1600

Pressing oven is set at 70 psi
 

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TheLabGuy

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Psi set too high, should be 67psi (might even have to go a little lower). Also, you are running too hot (reduce final temp),you're boiling your e.max instead of pressing it. Your final temp for e.max ingots will be different than LiSi. Also, I usually only press with whipmix formula one investment in 100 gram rings. If you have to do 200 gram rings, only had success using speed investment by ivoclar. Also, your hold times change a lot between 100 gram and 200 gram rings. (100 gram hold time 10 mins, 200 gram 25mins).
 
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Psi set too high, should be 67psi (might even have to go a little lower). Also, you are running too hot (reduce final temp),you're boiling your e.max instead of pressing it. Your final temp for e.max ingots will be different than LiSi. Also, I usually only press with whipmix formula one investment in 100 gram rings. If you have to do 200 gram rings, only had success using speed investment by ivoclar. Also, your hold times change a lot between 100 gram and 200 gram rings. (100 gram hold time 10 mins, 200 gram 25mins).
Thank you

Im currently going with the pre program would you lower the temp by 50? 100?
 
ps2thtec

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I am new to pressing and I am having an issue with fit and the texture, along with some complete failures.

I am using Microstar investment 20ml expansion liquid to 5ml distilled water with emax and Gc Lisi with same results

I have tried my burn out oven diffrent temps ranging from 1500 to 1600

Pressing oven is set at 70 psi

To begin, do you have manuals for both press materials. GC made theirs tough to find when I got some LiSi to try. I’ll post link. Page 30,31 has press #’s .Took several times
to get good results with my ivo oven.
When I first got into eMax I had a ney type oven. See my #’s below. Life got easier when I got my ivo ep3000.
My burnout temp is at 1565F here, for either material.
I only do fast burnout with CreamPress, dva product.

E323F150-2148-4FD0-9B36-3811F466E251.png


431965A0-CB37-4B85-BF2F-DD4BBF5F66E4.jpeg
 
TheLabGuy

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700 entry, 60c rate, final temp 920c, hold 10-15 mins, press time 8mins, 2 mins cool time. Depending on reaction layer determines hold time, lower reaction at 10 mins but don't go below 10 mins, if still too much reaction layer drop final temp in 5c increments till you get what you desire (a light reaction layer). This is for e.max. you'll have to lower the final temp to about 895c for LiSi.
 
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700 entry, 60c rate, final temp 920c, hold 10-15 mins, press time 8mins, 2 mins cool time. Depending on reaction layer determines hold time, lower reaction at 10 mins but don't go below 10 mins, if still too much reaction layer drop final temp in 5c increments till you get what you desire (a light reaction layer). This is for e.max. you'll have to lower the final temp to about 895c for LiSi.
Sounds about right. LiSi had better results…less reaction layer then Microstar. Use Micrstar on everything else. Sounds too hot too long.
 
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700 entry, 60c rate, final temp 920c, hold 10-15 mins, press time 8mins, 2 mins cool time. Depending on reaction layer determines hold time, lower reaction at 10 mins but don't go below 10 mins, if still too much reaction layer drop final temp in 5c increments till you get what you desire (a light reaction layer). This is for e.max. you'll have to lower the final temp to about 895c for LiSi.
Should I be running it as a SP press cycle or conventional press?
 
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Car 54

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I'm at a loss as far as offering any real "help", but, have you called Whip Mix tech support or emailed them some photos in case they need to run a calibration? Or, have you tried firing a shade tab of porcelain to see if it fires correctly at its recommended temp?
 
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TheLabGuy

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I set a sew program with your suggested parameters. And I got the same result.
Still too hot, lower final temp in 10C increments. You need to find your zone, where it still presses but little reaction layer. Once you home-in on your zone, you'll know, you will still get a reaction layer but not heavy at all, very light and presses even thin. Elevation plays a roll as well...I'm 900ft. above sea level.
 
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Still too hot, lower final temp in 10C increments. You need to find your zone, where it still presses but little reaction layer. Once you home-in on your zone, you'll know, you will still get a reaction layer but not heavy at all, very light and presses even thin. Elevation plays a roll as well...I'm 900ft. above sea level.
Ok thank you I will try that.

Hold time question, how come these other 3 ovens recommend a 25 min hold time?
 

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ps2thtec

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GC LiSi Recommends the 25 to heat their ingot. Ivo is a slightly different animal.
 
Mike2

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I used Microstar for years and 20:5 H2O is going to be a sloppy fit we have always ran 15 liquid to 10 H2O Your tight fits is the heavy reaction layer. My 2 cents
 
Car 54

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I'm at that same ratio, 10 of water and 15 of the liquid with Microstar.

edit: maybe just a paranoid thing on my part, but I use distilled water in place of tap water.
 
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ps2thtec

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In the OP’s first post there’s more than one thing going on.
**cracked ring
** reaction layer severe
**fits.
I wondered if the reaction layer was removed from the inside??
Was acid bath used to help blast it off?
In pic 5, that’s an awfully small button - ?one crown?
When the press is activated for eight minutes, that seems excessive, adding to the heavy reaction layer. My Ivo oven presses a ring in 1:12 to 1:20 . (that’s minutes and seconds)

oh, and did I mention the Super ring? 😉
 
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Still too hot, lower final temp in 10C increments. You need to find your zone, where it still presses but little reaction layer. Once you home-in on your zone, you'll know, you will still get a reaction layer but not heavy at all, very light and presses even thin. Elevation plays a roll as well...I'm 900ft. above sea level.
After many test runs and changes to my program this is where im at. I had very aggressive pitting texture that I faintly have just about eliminated by prining temp down in 10c increments . On my last two pressings one unit does not completely press. In attached photos one is at 12 min hold time the other is at 14 min hold time, the 14 min hold time pressed more than the 12 min. Here is my currently program

700c entry temp
60c rise
860c hold temp
14 min hold time
8 min press time
2 min cool
64 psi

The fit is good, just still some texture and one unit not completely pressing
 

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sidesh0wb0b

sidesh0wb0b

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After many test runs and changes to my program this is where im at. I had very aggressive pitting texture that I faintly have just about eliminated by prining temp down in 10c increments . On my last two pressings one unit does not completely press. In attached photos one is at 12 min hold time the other is at 14 min hold time, the 14 min hold time pressed more than the 12 min. Here is my currently program

700c entry temp
60c rise
860c hold temp
14 min hold time
8 min press time
2 min cool
64 psi

The fit is good, just still some texture and one unit not completely pressing
8min press time for a 100g ring? that might be your issue. or part of it.

what pressing furnace are you using (pardon me if i missed it)?
as stated above, most 100g rings press in 1min10sec-1min45sec here.

your latest pics look far better, though a bit "cold" hence the short press and the glossy look where it pressed short. your initial pics looked to be way scorched and over baked. which is why the major reaction layer is present. i would lean toward something being off in burn out, or pressing, or both.
 
TheLabGuy

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After many test runs and changes to my program this is where im at. I had very aggressive pitting texture that I faintly have just about eliminated by prining temp down in 10c increments . On my last two pressings one unit does not completely press. In attached photos one is at 12 min hold time the other is at 14 min hold time, the 14 min hold time pressed more than the 12 min. Here is my currently program

700c entry temp
60c rise
860c hold temp
14 min hold time
8 min press time
2 min cool
64 psi

The fit is good, just still some texture and one unit not completely pressing
You're getting closer, I would up your final temp 5C and make press time 10 mins as well. Now you are fine tuning your program...once you dial that bullseye in you will get consistent good results Everytime. It's kind of a pain in the backside but you learn a lot doing it. I will say for anyone reading this, a ivoclar oven usually presses right out of the box, no need to dial anything in. However, sometimes even them need some tweaks.
 
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You're getting closer, I would up your final temp 5C and make press time 10 mins as well. Now you are fine tuning your program...once you dial that bullseye in you will get consistent good results Everytime. It's kind of a pain in the backside but you learn a lot doing it. I will say for anyone reading this, a ivoclar oven usually presses right out of the box, no need to dial anything in. However, sometimes even them need some tweaks.
I would add more hold time also. For LiSi I have a 25 min hold at temp, the press time is less than 2 but it is automatic. (Zubler Vario Press 300) The most important thing now is to make 1 change and not a large change to dial it in to a perfect pressing. The reaction layer is caused by the time the glass is molten and in contact with the mold. The faster you can press the mold and get the material into a solid state the less the reaction layer.
 
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