Speaking of releasing from the mould; we reloaders use mold release that we get from any reloading source. Try Midway USA, or Graf and Sons in Missouri. I use it on my jig and spinner bait molds to get them to release easily. BE Careful using a knife, scraper, or abrasives on your molds because a deep scratch will make the release problem even larger. Use very fine wet or dry sandpaper and be careful with it. Then use mold release.
I have taught metals and casting at the secondary and university levels and have a masters in metallurgical sciences including hot metals tech, plus spent a lifetime making bullets and now going into making shotgun shot. Fluxing the crucible or casting furnace is the way to go no matter what common flux that you use.. It keeps the crud out of your lead ingots and consequently keeps voids from happening in your lures. Good luck with your casting and be safe!
