Dukes Foundry Part Twau

[Just Duke]

I fired up the foundry now that the back fourty is clear from bees.
I think I messed up though. Failing eyesight and safety glasses instead of my reading glass let me run the temp to high on the themometer. I hope I got all the zinc weights out on the first skim when I saw some stragglers floating on the top.
How much zinc does it take to contaminate a cast iron pot beyond use?
I did manage to only melt up half a dutch oven full.
I also cast up 1000 45 Long Colt and they look OK. HMMMM!
:castmine:
Still waiting on my Star luber and all the cool guy attachments.

TIA,
Duke

[imashooter2]

You say you cast from that melt and the boolits "look OK", so I'd say you have no zinc worries at all.

[docone31]

Unless you flux, match heat, and get the cast iron permeable, you will not get zinc to penetrate the iron. Same with lead. The oxides prevent any brazing of the metal.
If there is still some zinc in the melt, and the castings came out well, no worries.
I have some zinc in mine, and it is not an issue. I scooped the oatmeal out. Some will remain no matter what.
If it ain't broke, don't fix it.
Sounds good.

[Just Duke]

So I should be OK? How about the Lee 20 pounders. OK too?

[bigbird1]

I had the same problem with a batch, the top drys rainbow looking , but it still casts well so who cares, shoot it up.

[imashooter2]

You said you cast from that melt and the boolits were good. If the melt made good boolits then there wasn't any zinc in it, or the concetration was too low to matter. In either of those cases, you certainly didn't harm your smelting pot or bottom pours.

[docone31]

What is really devastating to pots is acid core flux. Any acids will accelerate oxidation.
If any acid core flux is present, heat it up, then shut it down.
I have a Lee 20 pounder. I have abused it for years. I knew nothing about zinc in casting. I poured away. I even mixed pewter into my melt to pour a nose cap for my Hawken.
Still using it, years later.
It is oxidation that eats the pot.

[runfiverun]

i keep my pots full and don't seem to have the problems i have heard about here.

[Just Duke]

I casted up a total of 2400 45 Long Colts with two Lee 6 cavity 255 grain moulds. All seems good. Cleaned the heck out of the pot afterwards though to eliminate any contamination if there is such a thing. Bullets all look OK.