Hello, everyone. Last weekend, I was casting with a two cavity Lyman 311008 with fairly soft lead-tin..mostly range scrap alloy. Bullets were dropping beautifully..fully filled out.
However..the last time I used this mould, I cannot remember having to go thru this: I am a dipper caster..pot is a 20# Lyman Mag-Dipper. With the farthest cavity..I mated spout with sprue hole c'sink & slowly brought both to vertical..less than 1 second later, I lifted dipper straight up & let alloy pour overflow cutter plate..mould is held at slight forward & downward angle so melt flows over front of mould..away from 2nd. hole. If I left dipper & mould together longer..there was a slight gas depression in bullet base..I tried everything I could think of & this was only solution.
On the near cavity..I found I had to keep dipper spout & mould tightly together for a 3 second count to have any hope of fill-out. I figured this was due to first cavity filled & venting was cut in half? Took me a while to figure this one out.
Like I said, I don't recall it happening before. I wonder if outside temp. or humidity could have an effect on casting?
Nothing in cavities, since I both washed out with brake cleaner & then with hot soapy detergent & old toothbrush.
That gas depression is puzzling, since I very carefully take a small 3 corner hard Arkansas stone & "break" the top edge on both blocks very very slightly..under magnification look like tiny V..with blocks together..don't want to overdo this, as fins will develope.
