A few melting questions

Hi all,
I have been a fishing tackle maker for a while and do a lot of lead pouring. I bought 100 lbs of what was sold as pure lead that the seller got from where they cut lead sheets to fit X-ray room walls.
It seems to be great stuff but I have a bit of trouble with what I think is lead oxide. It looks rusty color along the sides of the pot, also when I first get to the pot after letting it preheat it’s usually crusty brown on top, and can be kind of wrinkly for lack of a better word on top. Kind of flakey looking. I don’t have any pictures but can take some tomorrow if needed.
Is this just normal with pure soft lead or is it the pot too hot? It gets better and looks nice and shiny after I drop a pound or two in and skim it but the gets cruddy again.

I’m using one of the Lee bottom pour 10 lb melters. I usually keep it within 1” of the rim and on #7. I don’t have a thermometer or want to spend the cash.

If tin would help, how much per pound of lead should I add? I don’t want to make it too hard where it doesn’t fill in details of small fishing lure molds.

Also, how should I clean it after draining it? I’d like to clean the spout. I’m considering a respirator and a brass brush in a drill.

Thanks and hopefully I can start pouring for my 1911 when I get somewhere better to shoot.

Hi, welcome to the forum. :)

I wouldn't add any tin to the alloy yet. Keep it in it's pure state so you can alloy it to suit your needs in it's future, it ends up being easier that way. I only end up doing alloying in my casting pot when I calculate how much of which alloys I need to get where I want, especially important for you as you're going to figure out what works best for you as you go and guessing now won't do much good.

I might have read what you wrote wrong, but you are aware that adding tin will only increase fillout/detail transfer, right? Tin reduces the surface tension of the molten alloy and lets it flow better, that's the main reason for using it in sweetening wheelweight alloy for example, it's not to add hardness usually.

Having a lot of various colorful oxide is typical for pure lead, what are you using to flux? I didn't see any reference to what you're using, but I hope you used something! You need a source of carbon in order to reduce the oxide back down to it's metallic state, typically something like sawdust, paraffin, or beeswax is used. I add some right at the start before I even start to melt, then flux again when the pot is melted, skim off the carbon and start to pour ingots. After that initial skimming don't throw out anything you skim, it's good metal just oxidized! Just work around it and reduce it back down later.

You can probably get away without using a thermometer for now, just use some common sense. Running the alloy too hot will indeed greatly speed up the formation of oxide, keep it reasonable.

That's kind of normal for Lead sheet. All sorts of nasty looking crud will float up out of it.

I melt a lot of it to put into ingots for later.
What I do to clean the pot is stir/scrape around the sides, jiggle the needle, and lightly scrape the bottom with a real big flat screw driver.
I wouldn't bother to empty and brush it out. That and fluxing will float the trash out. Dislodge it, and it wants to float.
A little oxide seems to continuously form on a hot pot also, for me, it seems pretty normal. I just skim it off periodically.
Afterwards, doing a clean run for casting, I've never had any beasties go through or clog the pour spout.

Thanks guys! I use a regular white candle to flux with but I wasn’t aware it would melt down into useable metal again! I have also considered sawdust to leave a thick carbon layer on top to help prevent oxidization.

I thought tin was harder, seems I lumped it in with antimony in my mind, or I’ve just heard misinformation about the subject my whole career. That’s why I came here!

Well, you weren't misinformed about the tin, I may have been a little confusing in my post. It is indeed much harder than lead and can be used to harden it. Something like 1:20 or 1:10 tin to lead will give you a harder metal than pure lead. It's not especially hard though, and tin is expensive. If you're after hardness there are other, cheaper way to go about it.

Often times when we add tin to an alloy we aren't interested in adding hardness, we're trying to make the alloy more castable. This is pretty common if we're working with wheel weight or range scrap. The only part where you were a little off the mark is here, it does help a great deal with fillout as opposed to being detrimental to it.

As to using sawdust, you correct in assuming the carbon layer will act as physical barrier to oxidation, yes it will indeed turn your oxide back into usable metal. However I don't use a bottom pouring pot so I don't know the best practices for using one of those. I don't want to give you advice that will make a mess or clog your spout. Some people use kitty litter as a cover material?

Most (basically all) people clean up lead into ingots in an open pot before it goes into a bottom pouring pot to keep it clean, something to keep in mind.

Just spend some time lurking old threads, the knowledge contained here is unrivaled.

Hhudson welcome to the forum!!!
And like what was said, I use tin for fill out
of a mold. I have a Lyman 20lb. bottom
pour. And when I am making boolits
and the lube grooves do not fill out.
I add about a 2 foot piece of solder.:redneck:

Thanks all. They are premade cleaned 1 lb ingots that I’m using. I will look into finding some small pieces of tin. I have a few molds with a lot of detail that I wouldn’t mind a little help filling out!

Also if anyone sees this - sometimes my poured pieces are purple bluish tinted like the lead I can see in the top of my pot, is this an issue?

A good source of tin is Pewter (plates, bowls, cups, figurines etc.) pewter is apr 88-92% tin.

smelt and flux the pewter then cast it into 1/2 oz boolits then use the boolits to sweeten your lead alloy.

as said above the tin does make your lead alloy harder but it also helps it flow better. (harder isn't a bad thing if you have fine details in your mold

Quote:

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Originally Posted by Hhudson

Thanks all. They are premade cleaned 1 lb ingots that I’m using. I will look into finding some small pieces of tin. I have a few molds with a lot of detail that I wouldn’t mind a little help filling out!

Also if anyone sees this - sometimes my poured pieces are purple bluish tinted like the lead I can see in the top of my pot, is this an issue?

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The bluish tint is usually a sign of fairly pure, soft, lead. Not a problem.

Pure lead can turn blue, green, orange, etc. I’ve seen tin do it, too.

Flux it more. If it wont cast well, add 1% tin to help. If you want harder alloy, add some Lino or super hard.

Thanks guys! I turned down the temp to the 5 setting and poured a couple hundred jigs yesterday and everything went great. Still have a couple molds I would like to get some tin for. Pewter sounds like something I could find easily!

I add a small percentage of tin (like 1/2 %) to pure when I cast muzzle loader round balls. During storage, pure lead will oxidize, but if there is 1/2 % tin in there, it inhibits oxidation and will stay silver.
If you are painting your fishing jigs, this probably doesn't matter...but if not, and you want them to stay silver, add some tin.