Zinc in the mix

[Schwing]

I mixed up my first batch of ingots from wheel weights over the weekend. I used a dutch oven and just dumped them all in there and tried to keep the temp around 700. I was using a dutch oven and it spiked above 750 so I think there is a possibility of zinc. My ingots look kind of frosty on the bottom and they clink together with a metallic clink.

I have searched this and other forums for the skinny on zinc and have found everything from "You have to toss the entire batch in the garbage" to "Just melt them at a higher temp for better fill out and load em up!"

Can anyone give me the real skinny on zinc? Do you guys who use wheel weights put a lot of worry into it?

I am not too concerned about this batch. It is about 37 pounds and cost about $30 so It isn't the end of the world but I am really interested if it even matters or if I am hearing rhetoric from people who don't really know.

 

[Thompsoncustom]

I can tell you all kinds of things about zinc. I've made pure zinc bullets and some zinc alloys and when it comes to lead and zinc they don't mix very well and if you have over 2% zinc in your lead alloy it will stick out like a sore thumb. When your pot is melted and been liquid for a couple minutes if you stir it and it looks like oatmeal than yes there is over 2% zinc in there. I've casted this way with good results before but you can remove the zinc if you like just get some sulfur and flux it in and remove the zinc.

 

[ReloaderFred]

If you didn't get above 750 degrees, the zinc would have floated to the top in solid form. Zinc wheelweights will normally have the steel clip riveted in place, but I have seen them cast in place, too.

It's normal for wheelweight ingots to "clink" when dropped on concrete. That's the anitimony and tin, which should give you a Bhn of around 12, which I find ideal for most of my casting.

If there is zinc in the mix, it will show up when you flux your alloy for casting. It will be coarse and resemble oatmeal on top of the alloy. If you don't have this, then you're probably good to go for casting.

In the future, sort out any steel and zinc wheelweights before smelting. They're normally painted a silver color, whereas lead wheelweights won't usually have any paint on them, unless used on aluminum wheels, since some people paint them to match.


Hope this helps.

Fred

 

[USSR]

It's unlikely that any zinc wheel weights melted into the alloy at 750 degrees. In any case, try casting after melting some solder into the alloy. If the bullets fill out in the mould, you are fine.

Don

 

[Thompsoncustom]

If you didn't get above 750 degrees, the zinc would have floated to the top in solid form

Really depends on the alloy. No different the your lead alloy's having different melting temps but 750 is probably a good rule of thumb.

Now if you really want to blow your mind you can melt aluminum at 800 degree in zinc, sounds a little crazy but it doesn't really melt as much as it dissolve like salt into water but it works none the less and helps fill out with zinc bullets.

I've added zinc to lead alloys a couple times and mixed up some different alloys. And there is only two that I have found that zinc can be in there and not be noticed. One is under 2% and in this case it doesn't case any problems so don't worry about it. The other is pure Lead and pure zinc the lead sinks to the bottom of the pot and the zinc floats on top so you really never see any probably until you start weight bullets.

 

[homatok]

If you want to find out if you have any zinc in your alloy ingots, get some Muriatic acid (from your local pool supply house) and put a drop on your ingot(s). If it bubbles/foams you have zinc in your alloy. As mentioned it is possible to remove the zinc using a sulfur flux, or by melting the ingots below a certain temperature (I can't recall the exact temperature at the moment) WITHOUT FLUXING! the zinc should manifest as a layer of "oatmeal" like sludge on top of the melt and that can then be skimmed off. Hope that helps. There is a lot of information on zinc over on the "Cast Boolits" website.