Wax seperation on UCLA

sndmn2

sndmn2

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Trying to figure this one out. I had one miscast and luckily this one did cast out. It looks like it was cut with a thin disc. Some sort of speration or residue from the plastic sleave? Never had this before. 20171106_114320.jpg
 
JMN

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Done hundreds and never seen that happen. Very odd looking indeed.

If it happened to me I'd check my sprue technique and make sure I'm sealing it completely instead of seating it and assuming it sealed. Normal cavitation patterns would do nothing like that and a drawback from sprue feeding the pattern while cooling would be starting from the inside and grainier instead of sharp, smoothish, and outside.

There is definitely something in the path of the metal when it is cast that is making that shape, be it investment that oozed into a crack in the wax pattern, a chip or chunk that cut into the wax.

Did you notice when you devested it that there was investment in the crack? If there was, the only way that could happen is if the wax had that shape when it was invested, so something in spruing is the most probable place to investigate and hit paydirt.
 
sndmn2

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I understand what your saying. Here is the interesting part. It happened to me on the first attempt and I got a total miscast. So I had a buddy who does these all the time cast this one and he got the same result. The investment was more on the surface. Sorta hollow.We used a sprue with a reservoir and an additional vent sprue. I agree, I have never had this happen before and it doesnt make sense. This was very long casting exceeding the length of the plastic sleave it that matters at all.
 
JMN

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I understand what your saying. Here is the interesting part. It happened to me on the first attempt and I got a total miscast. So I had a buddy who does these all the time cast this one and he got the same result. The investment was more on the surface. Sorta hollow.We used a sprue with a reservoir and an additional vent sprue. I agree, I have never had this happen before and it doesnt make sense. This was very long casting exceeding the length of the plastic sleave it that matters at all.
So, check my understanding. When you devested, the cut looking areas had no investment in them to blast or dislodge.
That's more than just a few mosquito boogers past weird.Hmmmm
 
lcmlabforum

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Gremlins.
Kidding aside, it seems like it was a smooth void produced between the investing time and setting.
Or someone switched your ring out for Halloween to prank you.
LCM
 
doug

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Unless you're going to fire porcelain to this, I would use some low fusing solder and fill the area and move forward.
 
JMN

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Gremlins.
Kidding aside, it seems like it was a smooth void produced between the investing time and setting.
Or someone switched your ring out for Halloween to prank you.
LCM
Yeah, but that doesn't make sense either.
The investment was hard enough during setting and expanded enough that it pulled the wax apart off of the ucla, but liquid enough to fill the gap it caused and prevent metal from being in the gap when cast. Because if it were a pull apart only the gap would still be cast. A airgap in a hollow area after burnout is just as hollow as the rest.

The only thing I can make sense of it is if someone nicked it with a hot wax knife.
 
sndmn2

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Thanks guys. Im still coming up short of answers. Even if there was a slight separation in the wax I dont think the space would be nearly this large.
 
Car 54

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Did you change from wax to plastics sprues, and maybe it's separating where it's been luted during the vibration of investing?
 
JMN

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The only normal thing I can think of that could cause a straight flat area with mildly rolled edges is a hot waxknife incursion.

Are you putting these on the ring, or is someone else?

20171106_114320rb.jpg
 
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