Press rings cracking.

[Jenners]

I've been using the same Auto Press Plus furnace for a long time with Avante Micro Crystal. Same process and materials as always. I've never been super knowledgeable about pressing but they've always come out decent enough. We don't do nearly as much pressing as we used to but every ring for the past.. 5.. have cracked down the side. I usually am somewhat lucky that the internal surface is good and I'll have to grind away at the outside. I may press once every couple of weeks so it's been a very slow process of trying different simple things ... making sure the rings are flat, the oven is clean, taking time to burn out... but not too much time.... Nothing I've tried has worked. Any ideas on why these would suddenly start cracking?

Note: I tried doing a calibration from the manual on the oven. The instructions made no sense to me. Everything seems in order if I did do it right.

 

[JMN]

The low hanging fruit:
New box of investment?
New container of liquid?
Both inside the expiration date?
Verify air pressures?

 

[Jenners]

I'm not sure about the air pressure. The compressor runs like hell. I'll go back to the manual and figure that part out. For as long as I've had this oven, I don't know the functions well. It came pre loaded and its only had this one job.

 

[ps2thtec]

I've been using the same Auto Press Plus furnace for a long time with Avante Micro Crystal. Same process and materials as always. I've never been super knowledgeable about pressing but they've always come out decent enough. We don't do nearly as much pressing as we used to but every ring for the past.. 5.. have cracked down the side. I usually am somewhat lucky that the internal surface is good and I'll have to grind away at the outside. I may press once every couple of weeks so it's been a very slow process of trying different simple things ... making sure the rings are flat, the oven is clean, taking time to burn out... but not too much time.... Nothing I've tried has worked. Any ideas on why these would suddenly start cracking?

Note: I tried doing a calibration from the manual on the oven. The instructions made no sense to me. Everything seems in order if I did do it right.

Not sure if you have the manual that came in a binder so here is some trouble shooting pages. I haven’t pressed that stuff
in years.

 

[Jenners]

You know, that is helpful. I was looking at the the pressure gauge and the guide on what the pressure should be. The guide measured the pressure in a different way than the dial(I'm not there and can't recall). But according to the page you posted, my pressure may be too high. I think I was a bit above 6 bars ... and a while ago we had to muck with that air hose for another oven... so it's possible that the press oven got affected. I'll check it Friday when I'm back in and press a test. Thanks for taking the time to put the pics up.

 

[sidesh0wb0b]

check your burnout temp
check your investment liquid expiration
calibrate your press furnace

 

[kimba]

Has the liquid frozen in storage or transit? this can effect expansion rates adversley

 

[Jenners]

So yeah, the pressure gauge was too high. I'm not sure when that got changed... but I backed it down a bit. The ring didn't crack but the press wasn't complete. At least the big problem is figured out..the rest is tweaking.

 

[JMN]

So yeah, the pressure gauge was too high. I'm not sure when that got changed... but I backed it down a bit. The ring didn't crack but the press wasn't complete. At least the big problem is figured out..the rest is tweaking.

Thanks for the update.