In an effort to step up my casting game I recently upgraded from a cast iron dutch over and a turkey fryer with a bottom pour ladle to a brand new Lyman Mag 25 Digital bottom pour pot. I've had a lot of success with that method. I thought surely that adding an electric bottom pour pot with a PID would only help. That's where my issues started.
As soon as I got the unit I let it burn off the oil with no lead in the pot per instructions. I've casted with the pot twice now running probably 60lbs of lead through the pot. I keep getting what I can only describe as inclusions in my casts.
At first I was getting terribly wrinkled bullets and I chalked that up to me over oiling the molds. I took my molds and washed them with hot soapy water and sprayed them down with brake cleaner. I preheated my molds on a hotplate and set the furnace to 800 degrees and started casting. Those changes helped the wrinkles some but I'm still not getting satisfactory casts.
My alloy is mostly old plumbing lead pipes and drum traps mixed with clip on wheel weight all hand sorted and fluxed with saw dust and paraffin wax. I fluxed the lead in the Lyman pot several times with saw dust and bees wax thinking that perhaps I had some contamination in the pot. I emptied the pot to see if there was any obvious contamination in the unit, none that I could see.
So, those are the facts and I still have no idea what is causing this over 4 different molds. Out of the 60 or so pounds I've run through the unit I've gotten perhaps 50 or 60 keepers. I've attached pictures of the defects along with an ingot that I poured from the pot. This just has me scratching my head. Let me know what you guys think. Thank you.
Picture of the offending boolits in question
Picture of a lead ingot drawn down to empty the offending furnace
And a few pictures of some good boolits to show that I'm not a total noob and because I want to show off a little.
Thanks again for your help.