Is there any explosion hazard with an enclosed graphite crucible melting silver? the crucible volume is about 2 ounces.   The final design of the crucible will be enclosed tightly except for a small .5mm diameter hole at the bottom and a 1mm diameter hole at the top through which silver solder will feed.

I was wondering.  In my experiments should I worry about the thing exploding?
Silver will absorb oxygen readily from air while molten and spatter as it cools. This is hardly an explosion, but some care should be taken to avoid being spattered with hot particles ejected from the crucible or plugging the holes.