Stupid Press

[PGguy]

Hey guys,

What you think...not enough button?

I have the worst luck with pressing large investments. It was on the border so I added another ingot to be safe.

Im using Pressvest Speed. Using EP 3000 oven. Using the pre-program Emax LT 200g to press. 850 C to burnout for minimum hour.

What gives dude?

 

[dmonwaxa]

A single ingot would have been sufficient. Sprues are too long, and I believe the margins a re incorrectly positioned. Refer to manual for orientation.

 

[user name]

Not only would a single ingot been enough, maybe the extra you through in was too much of a heat sink..causing the problem. Check your burnout calibration, and sprues too long.

 

[Paul Drufva]

You can download in instruction manual from Ivoclarvivadent. Sprues are too long. Tops of patterns need to be even, i.e. all the same height.

 

[PGguy]

K, let me get this straight, you guys are saying my sprues are too long? lol

I have looked at the manual many of times, maybe Im just retarded. The one that didnt press was higher than other two.

K, ill get back to ya when i give it another go with multiples

 

[PGguy]

If anybody wants to put the effort in showing how they sprue multiple posteriors that would be cool to see

 

[TheLabGuy]

I burnout at 870C and sprues aren't suppose to be more than 3mm long. I usually go half that even. A thicker sprue rod may be more help than anything for you though.

 

[eddopak]

I think i would raise the temp about 10c,On a 200g.

 

[PDC]

I agree with "eddopak" on raising the pressing temp...the margin looks like a "cold shot" that you see on metal castings.

 

[dhdc]

sprues are way too long and by having the crowns on that angle you are asking the material to change direction too much.There is a plastic sprue guide that you wax patterns should fit into.You also need to spin you patterns round and have the highest points of the crown in the middle of the ring,where the heat is retained for longest.The weight guide for castings is very good and 2 pellets is overkill,this is the most sensitive material i have ever used and you need to follow instructions to a tee!!!!

 

[AL1]

Margins should be facing out and wax ups should be kept 10mm from top of ring and 10 mm from side, maximum.
Ivoclar sells a gauge for about 12 bucks, its quite help.

 

[PGguy]

The confusing thing is I used the sprue guide with patterns rotate like dhdc said with shorter sprues before. This is my compensating for the same results as photos. I just finally decided to post photos. I thought I followed everything to a tee before.

I will try what Labguy said because I have tried the rest already, but also go back to the old way of spruing like all of you suggest.

Thanks everyone

 

[paulg100]

my to cents

shorten sprues - 3-8mm according to manual, i always keep mine on the shorter side, the longer the sprue, the more the ingot will cool as it travels up the sprue and the more likely to get a poor result.

I dont think the angle is an issue, im pressing implant support stuff with vertical sprues to avoid the investment breaking so thats no problem.

And yeah the only other thing..heat.

Ive said this before on another post but my so called out of the box ep3000, set up and go, was nothing of the sort.

I had to dial the press temp in and im pressing at 905 on 100g now. (still gotta dial in 200g's)

You may need to do this also. Try raising the press temp by 5c and see how the reaction layer is. If its to much, then drop 2c and see if you still get complete pressing with sharp margins. I think the pressing temp may be more relevant than the burn out temp in this case.

remember

Incomplete pressings or margins..not enough heat.
To heavy reaction layer - to much heat.

Its a balancing act.

You probably know all this anyway but maybe something helps.

 

[Al.]

I tend to agree with Paul. It looks like a cold pressing.

Yes the sprues are too long.

I have found the spruing angles not that technique sensitive.

I always cram as many in as I can and sometimes the placement is not ideal.

Here are 10 thin veneers. Waxed between .3 and .4.

They weighed under 7.5 so I used 1 ingot but a 200 gm ring.

 

[PGguy]

Thanks Paul

Sometimes you just need a little refresher

Thank you x2+1

 

[rkm rdt]

"They weighed under 7.5 so I used 1 ingot but a 200 gm ring"

Al,why did you use a 200 gm ring?.

 

[Al.]

Ivoclar told me to flare the wax ups out sort of like spokes on a wheel.

The small rings force me to make them angled more straight up and down like for casting metal.

If I thought it was risky for me to press several in one ring no way I would do it.
It takes way too long to rewax and press vs using 2 rings.

 

[rkm rdt]

Interesting.

I've always chickened out and spurued 3 or 4 at a time with the 100g ring.

 

[stumpf]

I had same problem in the past. Use a simple sprueing guide!

 

[subrisi]

If I have more than 2 units, I use a 200 g ring. I also alway weigh the ring to get the exact wax weight. Do not press two ingots. If it is too much wax for one ingot, use two rings. Or buy the large ingots. When you say one hour burnout, do you count from the time you put the ring in the oven or from the time the temp raised again to 850 C? This is quite crucial espescially when you put more than one ring in the oven. It takes sometime up to 20 minutes to reach the final temp again. You have to comopensate for that.