Speaking of Zinc in the mix...

[STP]

I do some pretty weird alloy casting on request and recently had a new RCBS 20lb. ProMelt provided and a few moulds to use. The alloys include zinc, in increasing percentages. Weird stuff for sure...but it worked as long as I kept the temperature cranked up.
When the melt dropped below the level of the heating element (3 or 4 lbs left), the remainder turned to a slushy oatmeal consistancy, refusing to pass thru the nozzle. A Mapp gas torch directed on the nozzle does not help. Had to scoop as much as possible with a large spoon, then unplug the pot and step out to the driveway and fling the excess out, creating driveway tinsel...
My question is for those that have had the unfortunate experience of accidentally having some of those zinc "goobers" getting mixed into the melt. The remaining film on the pot wall when drained is tough to get out.
Has anyone had success in removing it by filling the pot back up with pure lead or wheelweight alloy, then flux, skim, and then pouring that out leaving a cleaner pot wall?

[ReAX222]

I have some crud that sticks to the side of my pot. I am not too worried about it, but I was going to try taking a piece of angle iron and scraping it out one day.

[Lloyd Smale]

I have occasionaly taken my pots out of the frame and had them bead blasted. Its pretty convient for me as my neighbor has a blaster but id bet any body shop would do it for a couple bucks for you.
I do some pretty weird alloy casting on request and recently had a new RCBS 20lb. ProMelt provided and a few moulds to use. The alloys include zinc, in increasing percentages. Weird stuff for sure...but it worked as long as I kept the temperature cranked up.
When the melt dropped below the level of the heating element (3 or 4 lbs left), the remainder turned to a slushy oatmeal consistancy, refusing to pass thru the nozzle. A Mapp gas torch directed on the nozzle does not help. Had to scoop as much as possible with a large spoon, then unplug the pot and step out to the driveway and fling the excess out, creating driveway tinsel...
My question is for those that have had the unfortunate experience of accidentally having some of those zinc "goobers" getting mixed into the melt. The remaining film on the pot wall when drained is tough to get out.
Has anyone had success in removing it by filling the pot back up with pure lead or wheelweight alloy, then flux, skim, and then pouring that out leaving a cleaner pot wall?

[STP]

In order to finish casting the requested number of castings in this batch of alloy, more has been ordered so I don`t run into the same problem. 5lbs of material won`t do 300 samples w/o the issue I described...

I`d like the pot as free of the last alloy before commencing with the next batch, so the results are not skewed.

Scraping didn`t faze it and media blasting seems a bit aggressive, but when I get finished with this mix I`ll try to rid it by pouring thru a full pot of a more "friendly" mix.

[ReAX222]

I just picked at the crud sticking to sides of my pot. It came off pretty easy, esp once I got out the flat bladed screw driver. I did have to tap the screw driver with my palm and the pot was at room temperature.

[dakotashooter2]

Wire wheel on a drill and a "dust mask".

[Springfield]

Sounds like you need a smaller pot, like a LEE 10 pounder. Will keep the lead level higher.

[STP]

Thanks for the additional suggestions.
However, I prefer to keep the pot`s interior as smooth as possible.
I`ve used the 10lb Lee for these requests, and the last one (new) "froze up" on the 4th cast, the pot could not give adequate heat even when it was dialed all the way to max temperature.

Weird stuff....