Is this what zinc does?

[pinshooter]

Scored 120 lbs. of wheel weights Friday morning at a tire store near work. They assumed I was casting bullets. and were pleasantly surprised that anyone would bring in a dozen donuts for a bucket of used wheel weights. Doesn't get any easier than that. :-D When I get new tires in a few weeks it will definitely be from them. Plan on leaving a bucket with my phone number and "DONUTS" on it too.

I went to melt them today in a cast iron dutch oven on a turkey fryer. Just hot enough to melt the lead and skim off any weights that don't melt (I'm assuming these are zinc) along with the clips. Went fine for the first 75 lbs. I put the last of the weights in the pot and took a break while they melted. When I checked the pot, it was full of silver 'oatmeal' on top of multi-colored alloy that turned blue (with red, yellow, & green as it cooled). All is not lost because I can sell the bad ingots to the scrap yard on the next trip, but was this caused by zinc? Will wirebrushing the cast iron pot be enough to prevent contamination of the next melt? Any information would be appreciated.

[Ohio Rusty]

When I have melted WW's, and I throw in a new handfull to melt, as they bring the temperature of the lead down, I get that what you call 'oatmeal'. When the lead starts getting back up to temperature, the oatmeal melts and lets me skim off the clips and crud that accumulates on the top. I've not seen lead contaminated with zinc, but I would think it would be usable for something if allowed to get hot enough to liquify the zinc.
Ohio Rusty

[pinshooter]

I turned the heat up and it didn't help. After skimming of the clips & fluxing I got what looked like lead with a blue/red/yellow scum on top. Never seen anything like this before. My understanding was that zinc caused the 'oatmeal' appearance, but the colors were bizarre. I tried to post a photo but I think the file was too large. Anyway, the first 75 lbs. of weights went just fine. Then rest can be sold to the scrap yard for more than I paid for the donuts but I hate to see wheel weights going to waste. My main concern now is what I should do to make sure there are no traces of whatever this was in my cast iron melting pot.

[Fireball 57]

pinshooter: Did you pour your melt into ingots? How did the melt fill the ingot mold? Did you notice the temperature on the melt? Why would your first melt be fine and not the second ? You might be okey. Try a few casting, with a small pistol mold OR a small cast iron ingot mold, heated by dropping the melt in it a couple times. Observe-Good luck!

[floodgate]

pinshooter:

I think you may be OK. If in the first pass you kept the temperature pretty well down, and skimmed anything that didn't melt, I doubt you got any zinc. The pretty colors come from a thin lead oxide film, and - as Rusty says - fluxing puts this and the "oatmeal" back into the mix. Go ahead and try casting with it and see how it behaves.

floodgate

[georgeld]

the coloration is because the melts overly hot. Don't hurt a thing.
stir it good, flux if you feel like it. oatmeal should stir into the melt.
IF it don't, skim it off and be done with it. easy enough.

Put a piece of sand screen over the pot, melt the scrap with a torch, dump the crap in a bucket/pile. trash burns up. what melts is bullet melt.

Keep the brass, jackets, clips etc clean and it can be sold for scrap too.
You get melt mixed with it, they don't want it even in the steel pile.

[44man]

If you have any zinc, a cold ingot will look like a galvanized rain gutter. Don't worry about the color.

[Bass Ackward]

Waste not, want not.

Proof of the taste is in the pudding.

[45 2.1]

If you have any zinc, a cold ingot will look like a galvanized rain gutter. Don't worry about the color.

I cast some 45 caliber Gould hollow points that looked like that over 30 years ago. They made wonderfull long range varmint boolits as they blew to pieces at 250 yds out of the 4570. All that was left of the boolit was lead bits about the diameter of a wooden pencil lead. Might be of use for someone who has some of this type alloy.

[Junior1942]

Invest in a thermometer. I use a Lyman, but there's several other brands.

[Dye]

pinshooter
Heat your alloy up to melting stage and take a small spoon and pour some of the oatmeal in small strips of it on a clean metal surface. Take a glass jar and fill it with muratic acid and sumerge the strips in it for 24 hrs. Caution do not seal the jar. Than you will know if it is zinc the acid will disolve the zinc.

Be carefull Dye

[44man]

Good idea, I like that! :mrgreen:

[leftiye]

Muriatic acid won't dissolve lead too? How about antimony?

[44man]

I don't think it will disolve lead and antimony will be in solution, not on top. So it just might work.

[SharpsShooter]

I've seen WW lead turn blue and yellow also during the smelting process. Makes a fine boolit.


SS

[floodgate]

Muriatic (hydrochloric) acid reacts with zinc to produce hydrogen. Keep it well away from open flame (Remember the Hindenburg!) . It does not react with lead or tin; I don't know about antimony.

Incidentally, aluminum and lye also react to make hydrogen. Don't ask me how I know....

floodgate

[pinshooter]

Thanks everyone for all the information. This is a great place. Although I don't post much, I've been lurking here regularly since the old shooters.com days. It was reading what others were doing that got me started casting.

Anyway, I already disposed of the clips & 'oatmeal' in the scrap metal dumpster at work, but I did make about 30+ lbs. of ingots out of the discolored stuff with the idea of selling it to the scrap yard. After fluxing (paraffin wax) it filled out the aluminum ingot mold OK, but it came out of the dipper in sheets rather than a stream. Also, the dipper (a 10 cent garage sale soup ladle) has bits of this alloy stuck to it, and where lead normally wipes right off when cold, this stuff wouldn't even come off with a stiff wire brush. I think I'll try remelting the ingots and fluxing more just out of curiosity though. Also, I found some muriatic acid out in the garage so I'll experiment with that too. If it doesn't work, no big deal as I believe the going rate for clean lead scrap in this area is around 50 cents a lb. right now which would just about cover the price of a casting thermometer (something I should have bought a long time ago, but out of neccessity I'm kind of cheap).

I'll be going back to that tire store in a few weeks to get new tires for Ol' Red (my current tires are almost worn out after only 127,000 miles) and you know I'll be bringing donuts. Worth keeping good people like these happy.