Okay, i got really frustrated today. I have been having this trouble with my 11bhn lead since I started casting bullets for the rifle or pistols. Never had any of these issues with my pure lead for BP shooting. I had smearing with 124 truncated cones for 9mm with smearing (Aluminum mold). Did some 30 cal bullets for the 30-30 and had a lot of lead pieces sticking to the MP mold that I still need to clean off (Aluminum mold).
Today I use the same lead alloy and melt for casting 147gn RN BB bullets for the 9mm with the MP mold (Brass). I have heated this mold over and over until it aged up good color wise for the patina. It started casting well as I heated on the hot plate and then with the lead a few runs. I started getting a coating sticking tot he sprue plate. It would be like the edge of the sprue puddle would leave a ring. I had some base fill out problems with the lead being 625 got up to 675 and mostly went away but not completely. I would fill the mold and watch the sprue solidify and count yo ten and bang the sprue plate open. If good into the bucket in not on the towel. The lead got up near 700 and I counted to twenty before opening the sprue plate and it seemed good. Then I got smearing. I got out the propane torch and heated the sprue plate and it got hot enough and I used a towel and off it came. A slight trace could be seen still of where it was before. The mold I heated longer and could only get some off. I tried to cast another one and it smeared awfully and I counted to over 30 on this one.
Maybe the mold was too hot? I read on here make it hot and go.
Maybe this alloy has trash in it?? I cast a while and keep getting a scum on the surface. I scrape it off and keep casting fluxing doesn't seem to change it. My pour ladle has seemed to be covered in lead trash lately and adding the ladle to the hot lead pot makes more scum surface.
Maybe something else? I am wondering if I did something wrong or I have contaminated lead with some of stuff like zinc or other metal. I have no troubles with pure lead and this stuff just is not working.
Also, once I solve this how do I clean all these molds and the pot?