zinc in my lead

[dearslayer]

My first time melting WW's was this past Sunday. I went through about 75% of my 3/4 full 5 gallon pail checking by hand for lead versus Zinc/ steel and figure if I kept the temp down to around 650 the remaining 25% would melt and I could avoid sorting by hand ( guess I should have just done the rest and I could have avoided this post ) . I bought a Lyman temp probe for this purpose. I did try to maintain the temp the best I could but would have to increase the flame under the pan when adding more WW's to the mix to get it back up to temp to melt so I guess it was at these times I should have paid better attention and used the gauge more often. Anyhow I tried to cast some .40 S&W boolits last night and no matter what, I could not get a decent cast. Mind you this is only my second time casting boolits so what the heck do I know. My first attempt with 9mm a couple weeks ago with already cast lead that was gifted to me turned out great ( for a rookie ). So when melting this newly cast lead in my old Lee pot it looks normal with none of the porridge looking stuff in the melt like I've read about. I guess my question is ...do I have zinc in my lead or could it be that my temp in the pot is not high enough or my mold is not hot enough or a combination of both. It seems like the pour isn't pouring fast enough??? and I'm not getting fully formed boolits and there are a lot of distortion/ wrinkles etc and the edges are not sharp and they are somewhat rounded.
I emptied the pot the best I could and used some of the gifted lead to see if it made any difference and although not perfect they did come out much better than the previous ones. What is the best temp to have the lead at to cast?

having trouble attaching photos.

[Tar Heel]

The liquidus phase of the melt with a zink alloy is much higher than lead. When I accidentally got zink in my melt there was a bluish sheen on the top of the melt. A significantly higher temperature was needed to flow the metal. I had the temperature rheostat all the way up and had to leave it there. I am averse to zink in my bullet alloy since I don't want to zink coat my alloy pot, molds, or barrels. For me, the alloy with any zink is problematic. Can't help you with the precise temp since my thermometer pegged out.

[Bloodman14]

As I understand the theory, use some sulfur (rose dust, local farm supply store) to chelate the zinc, removing it from the alloy. There is a thread on this process, search for it on this forum; lots of good info.

[toallmy]

If you don't see oatmeal your probably ok with your alloy , it's just a not the alloy you have been using . I ran into several problems when I first started casting that all looked like I had zinc in my alloy . After sticking a thermometer in my alloy I rediscovered everything I had read about melting temperature between pure / coww's +&- tin as well as mold temperature . My poor old propane burner could barely melt pure so several times I thought I had ruined a large batch when rendering my alloy . Then a member kept telling me to preheat my mold to get good fill out until I finally tried it . Even adjusting your flow could cause the problems you have described .
Thanks Bangerjim

[GregLaROCHE]

If there are no signs of zinc on the surface, you’re probably ok. Make sure you flux well with sawdust several times. Try increasing the temperature of the alloy and keep checking, until the boolits start to get a frosty look. Be 110% sure the mold is oil free.

I don’t use wheel weights, but I think most people add a bit of tin to the mix. It sure make casting good boolits easier than pure lead. Finally, don’t get discouraged. Keep casting over and over and you will be surprised how you will get better at it.

[dearslayer]

The thing is I don't see any difference to the melted lead in the pot other than the sprue ( is that what it's called ... the big overflow blob on top of the mold when pouring ) looks a little frosted. Maybe I need to turn the temp way up as "toallmy" suggest. Wish I could attach photos as it shows more clearly how the boolits look and form.

[dearslayer]

If there are no signs of zinc on the surface, you’re probably ok. Make sure you flux well with sawdust several times. Try increasing the temperature of the alloy and keep checking, until the boolits start to get a frosty look. Be 110% sure the mold is oil free.

I don’t use wheel weights, but I think most people add a bit of tin to the mix. It sure make casting good boolits easier than pure lead. Finally, don’t get discouraged. Keep casting over and over and you will be surprised how you will get better at it.

I cleaned the new mold with dawn dish soap the day before using it. I don't have any tin so will have to get some. Some suggest solder .... is normal plumbing solder ok to use or no? I want to stay with this as I'm really enjoying the challenge however it is a little frustrating

[AlHunt]

The thing is I don't see any difference to the melted lead in the pot other than the sprue ( is that what it's called ... the big overflow blob on top of the mold when pouring ) looks a little frosted. Maybe I need to turn the temp way up as "toallmy" suggest. Wish I could attach photos as it shows more clearly how the boolits look and form.

Are you checking the temp of your casting alloy? If it first melts around 620f, I'd think you don't have zinc in it.

[dearslayer]

Are you checking the temp of your casting alloy? If it first melts around 620f, I'd think you don't have zinc in it.

I'll have to check .... If I put say 4 bars in the pot when should I check the temp??? as soon as all 4 bars are completely melted or when they just are starting to melt??

[Sasquatch-1]

You never said what the problem is with the bullets you are casting. Are they wrinkled, are they brittle are you not having good fill out?

As far as solder for the tin content, check the label. Old school solder (which you can still find) was somewhere in the vicinity of 40 to 60% lead with the remainder being tin. I believe lead free is somewhere around 95% tin with the remainder being a non-heavy metal such as silver and copper mix. Solder will definitely be an expensive way to add tin. Read a few of the pewter threads and start looking for pewter at yard sales, flee markets, Goodwill and Salvation Army stores.

[AlHunt]

I'll have to check .... If I put say 4 bars in the pot when should I check the temp??? as soon as all 4 bars are completely melted or when they just are starting to melt??

I put the thermometer in early, usually with whatever I'm melting and leave it in the whole time I'm casting. At around 620F my COWW melts. On my thermometer. Thermometers can vary or get damaged, so for me it's a check that it's doing what I expect.

Then I cast in the mid to upper 700s. Others think that's too hot, but it works for me. I like frosted bullets.

If in doubt you could put your thermometer in boiling water to be sure it's at least accurate at 212F.

If you don't have porridge, I doubt you've got a lot of zinc, if any. People have reported success casting with a small amount of zinc. I'm not going to try it.

[dearslayer]

You never said what the problem is with the bullets you are casting. Are they wrinkled, are they brittle are you not having good fill out?

As far as solder for the tin content, check the label. Old school solder (which you can still find) was somewhere in the vicinity of 40 to 60% lead with the remainder being tin. I believe lead free is somewhere around 95% tin with the remainder being a non-heavy metal such as silver and copper mix. Solder will definitely be an expensive way to add tin. Read a few of the pewter threads and start looking for pewter at yard sales, flee markets, Goodwill and Salvation Army stores.

Yeah sorry...both lack of fillout and wrinkles.

[dearslayer]

I put the thermometer in early, usually with whatever I'm melting and leave it in the whole time I'm casting. At around 620F my COWW melts. On my thermometer. Thermometers can vary or get damaged, so for me it's a check that it's doing what I expect.

Then I cast in the mid to upper 700s. Others think that's too hot, but it works for me. I like frosted bullets.

If in doubt you could put your thermometer in boiling water to be sure it's at least accurate at 212F.

If you don't have porridge, I doubt you've got a lot of zinc, if any. People have reported success casting with a small amount of zinc. I'm not going to try it.

I think I'll try raising the temperature..

[Sasquatch-1]

Try some tin.

[dearslayer]

Try some tin.

If I put let's say 5 1 lb ingots in the 10 lb pot what percentage or how much tin would I need to add?

[CastingFool]

3.2 oz of tin will give you 2% , in 10 lbs of lead. To test for zinc, try a few drops of muriatic acid on one of your ingots. If it doesn't bubble or foam, there is no zinc.

[dearslayer]

3.2 oz of tin will give you 2% , in 10 lbs of lead. To test for zinc, try a few drops of muriatic acid on one of your ingots. If it doesn't bubble or foam, there is no zinc.

I'll have to see where I can buy Muriatic acid.

[oley55]

To the OP, per already discussed, you probably do not have much zinc in your alloy, but...............relying on temp control to sort your zinc from your coww is hit or miss at the very best. The issue here is the heat of your pot can and will be well above your target temp until there is enough melted lead in the pot to even out the temps. The pot may well be over a 1,200 degrees and zinc weights are being held down by many pounds of unmelted weights. The result is something has to melt to get the process going and any trapped zinc will get melted.

Sorting is a pain (and dirty) but you really should sort and then use temp control to catch the mis-sorted zinc weights. I test cut nearly every weight just to be sure, but there is still a chance I tossed a zincer into the wrong sort pile. Although I haven't found any floating zinc in my melts, I have had a couple steel weights pop up. That is my indicator I have mis-sorted. If I mis-sorted a couple steel weights, I'd be nuts to think I didn't do the same with a zincer or two.

I do/did use a thermometer to carefully control my temps for my first 5 gal bucket and made marks on the regulator knob/dial as base or standard setting. I've come to the realization smelting wheel weights is a slow process at my set temp marks but cranking up the heat is an opportunity to screw up. So I don't. If it takes 45 minutes for the melt to start, so be it (a cover over the pile of weights will help).

There is a lot more zinc, tin and pewter information to be found in the "lead and lead alloys" section, https://castboolits.gunloads.com/for...nd-Lead-Alloys

[Wayne Smith]

I'll have to see where I can buy Muriatic acid.

It's pool acid. Your local hardware store should carry it.

[oley55]

I'll have to see where I can buy Muriatic acid.

Muriatic acid can be found in any paint department or store. The problem is I can never find it in smaller volumes (less than a gallon). Although the plastic containers do not leak, over time the acid leaches through the plastic bottles in a vapor form and will attack any metals near by. Store you acid well away from anything you care about.