Bright idea; bad outcome.

[NyFirefighter357]

I too used a sinker mold. This one is a cast iron flat sinker mold that I left the mold blocks open and poured into each side. As you can see the alloy is 95/5.

[fredj338]

I cast straight pewter into a six cavity Lee 452-255 RF mold and have not had problems. I preheat the mold and open the sprue plate rather quickly, maybe 5 to 7 seconds after pouring.

You beat me to it. You can also just pour into a metal tsp. Adding tin isn't rocket science, so +/- works just fine. Also a single cav in a 4cav will usually easily cut the toughest sprue.

[dverna]

Might be a good use for an old screwed up bullet mold. Drill it out to size desired, and bang away on the sprue cutter with hammer if need be. Would not be difficult to make a HD steel sprue plate with a slightly smaller hole for easier cutting.

[Big Dipper]

I use a mold for strap weights for my duck decoys. I pour them alittle thin and snip off what I need with tin snips. They are also easy to store.

[GregLaROCHE]

Try hotter temperatures and cut the sprue as soon as possible after pouring.