Tips for keeping my Lee 4-20 from rusting?

[ageingstudent]

Let me apologize for initiating a thread drift, when your OP was about keeping your pot from rusting. My Lyman ingot molds also have a skim of rust on them (from when I bought them well used), and I have never worried about it introducing impurities. If i wanted to get them nice, black and shiny again, I'd need to use a hot kiln that got to 2000°F and introduce propane, natural gas or motor oil. (the motor oil is a super nasty mess).
Bentonite - If that's what cheap, clay kitty litter is made of, yes.
The purpose is not to draw off impurities, but to prevent the continual surface oxidation.
My opinion here :

• In a bulk melting pot, the lead may get as hot as 900°F. The point of the original melting is to remove the impurities from the scrap lead I'm melting. Filth, oxidation, whatever other crap is in it. It forms a dross on the top, and if you've noticed, as soon as you skim the dross off, a white film will form again. If you read up on it, it's likely lead carbonate. The kitty litter forms an insulating layer. Do I know whether or not it works? Not really, but I like to think it does. At least I'm not looking at a hot vat of lead turning white. I would find things like wheel weight clips floating in there. It's funny to see steel floating in a pot.
• You don't get lead hot enough in a reducing atmosphere to remove oxides from it. You'd need to be pretty hot for that, though I do not know what the temperature of that reduction reaction would be. It's an old potter's trick to get iridescence in the glaze on pots.
• When I go to pour, the last thing I'll do is remove impurities. I'll skim off the kitty litter, and then I'll mix in some copper sulfate crystals and it will remove zinc from the melt in exchange for the copper. Makes a white crystalline substance on the top - epsom salts. Skim that off too.
• Then I'll set the pot on a stable pivot and pour ingot molds, moving them in and out from underneath. Welding gloves, safety goggles, etc.

I dinked around trying to get a higher percentage of copper in my melt for increased hardness, but I couldn't get the melt hot enough without it becoming a fast oxidizing, smokey mess. I gave up on that and settled for just casting something between Lyman #2 and linotype. I have an induction melter now, but I've not tried that yet. If it works, I also have ~100 lbs of manganese to try.

I'm still waiting for you to come up with something for that model 81 I sold you. I always wanted to make a lead load for that gun that would function. Never got around to it darn it

 

[Dr Prepper]

Its really tough finding the time to stay in the loop on pertinent current events and research on the side, work a job, study who to vote for, and then also work up loads and everything else on top of it. Better hope your in good health or you don't stand a chance.

 

[P7M13]

I'm still waiting for you to come up with something for that model 81 I sold you. I always wanted to make a lead load for that gun that would function. Never got around to it darn it

And I just bought a Gibbs mold, .310 x 150gr just for that gun. I'm still planning on a visit to the desert some day, even though I've changed jobs.

 

[ageingstudent]

And I just bought a Gibbs mold, .310 x 150gr just for that gun. I'm still planning on a visit to the desert some day, even though I've changed jobs.

Always welcome here brother you. I'd love to see you.

 

[JO JO]

It's hard to get a good roll crimp with them.

Try a clear overshot card

 

[Dr Prepper]

Try a clear overshot card

May be true, although from his previous post I'm sure @CLT65 is aware of those. But you never know. There are also the overshot cards which aren't clear, but MUCH cheaper.

My BPI antique roll crimper has the option to swap the pins around so they are square and can do a square crimp on the end. That might be a helpful option. Might not feed as well for semi auto's though.