Will It Work? Investment repair

[user name]

What a day. Ive been busy working all weekend, but doing my favorite tasks: e.max. I spent alot of time on an anterior bridge wax-up, invested it in a 200gm ring. i invested it with microstar, bench sat for 18 minutes, removed the ring and let it sweat off some moisture for another minute...not quite long enough.

I placed it in a 845c oven, (theres a reason I dont do 850). Anyway...about 8-10 minutes later I heard that gut-turning muffled pop. Damn. Shut the oven off and removed the ring with about 1/4-1/3 of a side blown off. Looking into the plunger hole it was evident that the pattern was on the other side of the ring.

I let it cool off, carefully excavated some gouges out from the rest of the ring to create more retention, sized up a big bottle of ibuprophen to use as a ring. I stuck my fractured mould onto a piece of baseplate wax and centered and secured my make shift ring. I mixed up some more microstar to the same ratio and while it was mixing I brushed some of the same liqiud/water ratio onto the dry ring so it wouldnt suck the moisture from my new mix.

Ill let it set over night and heat it up sloowww in the morning. Whats your bet...? Will it press nice?

 

[Hary]

I have done with metal casting ring and it worked. I don't know with e max because there is some pressure that is applied with the plunger so if
you can use a metal ring around the broken ring with the same technique you used.:noidea:

 

[Summit harvest]

Why did it break? As winter hit here in Minnesota , my model room temp dropped to 66 f and my investments began breaking. Adjusted room temp and everything back to normal, very temp sensitive .
Good luck with the press

 

[RileyS]

You can buy a metal band thing at auto parts store.we've used it and saved a few.

 

[user name]

Run it through the press with the metal ring on it? Do you use any ring liner to allow for some expansion?

 

[Javier Ricalde]

I did it once but did not work because the fracture was also towards the inside of the molds that I leave the wax didn't material but was released so that he could not be adjusted by the internal surplus

 

[2thm8kr]

I find that buy the time I go through all the hoops
to make something like this work, it would have been
faster to just rewax and invest again.
Good luck on your endeavour.

 

[RileyS]

2oothmaker is probably right. We would just get it about as tight as it would go, without really cranking on it..."finger tight"
report the results!

 

[user name]

More details: When I made a new ring to reinvest it in, it was aprox. the diameter of a 300gm., but slightly over. That gave me about 8-10 mm more investment around the sides. I had to slightly bevel the end to get it to seat on my press platform. It appears to have pressed and is cooling off. Ill know in an hour...

 

[user name]

Whew. It worked. Now...I just need to remember to hold on to the bridge and not the button while Im cutting it off. Learned that the hard way too. I dont have carpet so my floors are harder than falling ceramics.

 

[JohnWilson]

Glad it worked, I would have never attempted it, I figure the time and the potential loss of materials do not make it a safe bet.

As for investment, We were using formula one for everything in our lab, including emax, we went through some major headaches with big rings doing exactly what you experienced. We ended up going back to Ivoclars speed investment and we have no had one ring do this since. Costs a bit more but all it takes is one ring to fail and the cost is not an issue.

 

[2thm8kr]

Whew. It worked. Now...I just need to remember to hold on to the bridge and not the button while Im cutting it off. Learned that the hard way too. I dont have carpet so my floors are harder than falling ceramics.

I think you've earned a little nap time.

 

[RDA]

Try tilting all of your rings against the wall of the burnout furnace. This cured our ring "pop", we've been doing it this way for years no problems. We have done this with Fuji-vest and Galaxy II.

 

[Flipperlady]

Place vent sprues ?

 

[EJADA]

This is from bad HS. IS IT A NEW BOX? If so tell Jensen to send a new box out. I have done this just make sure it's a different lot#.

 

[NicelyMKV]

I used Microstar for years. One day we started getting the tops blowing off the rings in the oven? I assumed it was bad investment because we were still doing the same thing we always did? After tech support and a few more months of tops blowing off sporadically, I went back to Ivoclar with zero issues? I just thought it was odd it just started happening out of the blue after years of use?