Not quite a casting question...but;

Anyone know if lead reacts with tung oil?

I coated the inside of a wooden ammo brick I made with tung oil and the lead of the soft points keeps getting a white coating...

Thanks

Can’t give you a definitive answer but tung oil dries and what you’re seeing could be the result.

Thanks Dan.

I wonder if it is corrosion (the brick seals up pretty tight and after a month still smells of something inside)

The white coating looks almost like the deposits on a battery terminal, but the brass and copper seem unaffected..

Found something courtesy of the Canadians (preservation of something or other ) website:

White corrosion on lead is usually caused by exposure to volatile organic acids such as acetic acid (vinegar).(elsewhere it says acetic acid often comes from wood products)

Thanks

I store a couple of milk crates of lead outside. Eucalyptus leaves fell on them and decomposed leaving that white film. I washed it off with water, let the lead dry, and casted with ease.

Thanks RG.

I guess leaves are wood products...

Hope all is well in the Republic.

Lead oxide. Lots of cheaper 22 ammo that is old gets an oxide skin on it enough that i won’t reliable feed into the chamber of target pistols. Not all bullets oxidize like this but those using a harder alloy with zinc certainly will. Most casters shy away from zinc in their mix but commercial ammo not so. I doubt your tung oil is responsible but there are a lot of products on the shelf these days calling themself ‘ tung ‘ oil and most are formulated for ease of application. Todays users want faster drying, faster build up etc. so these products have lots of driers in the mix and maybe these chemicals are at play.

Rick

Could you provide a source for this please? I'm pretty certain that is not correct, on the basis that I've cast with remelt from a lot of commercial bullets and never found any trace of zinc. Zinc messes up lead alloys so badly that I'm pretty certain no commercial manufacturer would use it either; even lead wire for bullet cores starts as a melt at some point, and zinc turns that melt to clumpy oatmeal.

I'm guessing you are thinking of antimony rather than zinc. Antimony (Sb) is a common element in lead alloy and is used to control lead hardness, both for casting and for swaged lead commercial bullet cores.

I got a tour of the Nosler facility a number of years ago, and being interested in lead and lead alloys, noticed they had rolls of lead wire (for bullet cores) labeled with different percentages of antimony; IIRC the highest was 12% which is quite a lot and makes a pretty hard alloy. There were also 2%, 8%, etc and I assume pure (0%) as well.

I pretty much agree with you but I was talking about 22 rimfire bullets and they are swaged not cast. I’ve cast with small amounts of zinc in some scrap before. It’s doable at high temp and gives you a hard ass shiney bullet. I wouldn’t recommend it but if you got a stash and want to play around it can be done.

Checking back..
Thanks for additional input.

My situation was the Spire point of a commercial cartridge in the box I built.
As of last week it would still develop a white crystalline coating on the lead tip. That is about six months after I built the thing....

The place was to use it for load development, apparently I need to leave the top off until it cooks out whatever is the cause of the deposits....

Zinc pretty much ruins a good casting alloy, in my experience. It changes the surface tension of the alloy, basically doing the opposite of tin. It causes moulds to NOT fill out sharp edges. The bullets are often undersized. You can do it with round ball moulds, if you actually want them hard and undersized, or some blocky bullets with basically flat sides that you want undersized. Bullets with any detail lose that detail. It seems like the zinc wants to migrate to the surface of the bullets and form a hard shell with high surface tension.

That's been my experience. I have had a couple successful experiments removing zinc from an alloy using copper sulfate.