I have been lurking here for a couple years, reading, studying, and learning. I joined awhile ago and have kept reading. I am stumped right now. I am trying to cast 9mm. I have started competition shooting and if I am too continue I need to cast. I sell tires for a living so for me lead is free. I have a few hundred lbs saved up. I have tried Lee 6 hole molds.....with a little success. Then they seem to get sprung. I figured I got them too hot. So Midway had Lyman steel molds on sale and I picked up a 4 hole 147 grain at .357. I carry 147 grain 9mm so I want to mimick my carry round for competition. The Lyman mold only gave me about 90 usable boolits out of around 200. I am getting some trash that sticks to the mold and will not come off. Looking here I see to heat it up and use bees wax to remove it with wood. I have gotten some of it off......but not enough to get the mold to close all the way. I was casting with my melt at about 750, and with a hot plate I tried to keep my mold at 400, but according to my temp gun it said I was more like 300. Reading here I know the temp gun isn't the most accurate......but it's all I have. I am using the Lyman digital thermometer for the melt temp. Again, I know it's not the best.....but better than nothing I would assume. I found I had my Lee drip o matic turned up way high in the past....no wonder I wrecked the aluminum molds.
How agressive can I get cleaning my steel mold? I have not used any brushes on it. Can I use a brass brush? I like this boolit design, so I don't want to wreck this mold. My lead is a mixture of clip on and stick on wheel weight. I am fluxing with sawdust, then with bees wax. Then I put more sawdust on top to keep on top while casting. I am sorry for the long post.....just trying to give the experts all the info so I can get the right answers.
So I am heating up my mold and hitting the dirty spots with a propane torch......and then melting bees wax on the stuck on lead/tin/whatever the stuck on stuff is, and scraping with wood sticks to try and remove the gunk. When not in use the mold is covered in kroil for a couple days for rust protection.