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<blockquote data-quote="JMN" data-source="post: 283875" data-attributes="member: 8469">A well built sprue system will have the objects being cast jn the coolest part of the ring, or the part that will cool fastest if you prefer, and the spruegates, runner bar and feed from the button and then the button -in that order- in the parts that will&nbsp; cool slowest so that the desired parts wil be fed until they cool.In practice it&#039;s near impossible to do right every time, but you can always get the gastes and bar/feedlines to be hotter than the cast parts.With co/cr it is even more critical than normal to not overheat. If the remainder in the casting crucible does not come out like picking up a piece of foil it is being overheated. When using multiple ingots they may not look as if they have merged as HN ingots appear, and that is okay.Another way to tell also, NP is overheated if you can see that the oxide layer broke/cleared.Side note, if you are casting this by hand without welders glasses you are asking for trouble. Get some. You can acheive high enough energy output to cause irreperable retinal damage just like watching a weld.Might be some useful info here for you as well, Al put up some nice sprue pics in this thread:<a href="https://dentallabnetwork.com/forums/threads/holes-small-pontic-holes-caves-into-the-pontics-orinto-thick-metal-supports-imake.15129/" target="_blank">https://dentallabnetwork.com/forums/threads/holes-small-pontic-holes-caves-into-the-pontics-orinto-thick-metal-supports-imake.15129/</a>If you find issues are still giving you a bad day, put up pics before you cut it off. Both sides, from bottom(metal entrance)/button and from the margin/metal stop side.</blockquote>

[QUOTE="JMN, post: 283875, member: 8469"] A well built sprue system will have the objects being cast jn the coolest part of the ring, or the part that will cool fastest if you prefer, and the spruegates, runner bar and feed from the button and then the button -in that order- in the parts that will cool slowest so that the desired parts wil be fed until they cool. In practice it's near impossible to do right every time, but you can always get the gastes and bar/feedlines to be hotter than the cast parts. With co/cr it is even more critical than normal to not overheat. If the remainder in the casting crucible does not come out like picking up a piece of foil it is being overheated. When using multiple ingots they may not look as if they have merged as HN ingots appear, and that is okay. Another way to tell also, NP is overheated if you can see that the oxide layer broke/cleared. Side note, if you are casting this by hand without welders glasses you are asking for trouble. Get some. You can acheive high enough energy output to cause irreperable retinal damage just like watching a weld. Might be some useful info here for you as well, Al put up some nice sprue pics in this thread: [URL]https://dentallabnetwork.com/forums/threads/holes-small-pontic-holes-caves-into-the-pontics-orinto-thick-metal-supports-imake.15129/[/URL] If you find issues are still giving you a bad day, put up pics before you cut it off. Both sides, from bottom(metal entrance)/button and from the margin/metal stop side. [/QUOTE]

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