Black line on margin after sintering in Argotherm

[deadhead]

So we finally milled and Sintered our first Sintron unit. Results look great except that we ended up getting a black line(ring) around the margin. After talking to AG they said it sounds like we had a small gas leak from the tray(meaning that we may not have the cap and cover completely on). Just wondering if anyone has ran into this issue because when we went through the process to sinter everything went together nicely just like the pictures showed, so I dont see how we could have had a leak, plus we ran all tests before hand and everything came back good to go

 

[deadhead]

Here are some pics of the inside of of our argotherm. Got white scuff on inside and tray. definitely looks like oxygen got in somehow

 

[adamb4321]

Sometimes happens, doesn't seem to make any difference. Probably the outer flask wasn't quite seated properly

 

[deadhead]

thats what we were thinking. after checking fit and finishing case, the line didnt cause an issue with final restoration. thanks for the response "adamb4321"