Oatmeal on top of lead melt questions

[chutestrate]

After all the advice I received on my mold question I believe I need to address another issue that was pointed out to me. Oatmeal on the top of my lead. Chances are it's zinc, and doing multiple fluxing/smelting...whatever word you choose to call it, with sawdust will clean it up a lot.

I questioned if there was a way to minimize removing alloys I want. Did some reading, and came away with the sense that if I kept my casting temp around 700 Fahrenheit that the zinc would not melt into my alloy and be captured by sawdust fluxing.

Am I correct, or are there better materials and ways to do it.

I'm finding this all quite interesting, and enjoy learning the process.


Or....in the end if I'm getting good fillout with what I have leave it alone, and buy some good certified alloy for hunting applications. Naww, what's the fun in that.

Thank you all for your guidance.

[MBTcustom]

The oatmeal on top of your melt is most likely undissolved alloy. I've dealt with it myself, and XRF tested it for content and found it to be surprisingly close to the alloy it came from.

[454PB]

What Tim said. Crank up the heat and see if it melts in.

[bhn22]

Flux the pot again. Often times it ends up being dirt or some other trash that didn't flux out initially. I tend to use sawdust for initial fluxing, then something like paraffin for the final round. It just works better to me somehow. You can usually pick up childrens crayons at the Goodwill store for practically nothing. Old candles work fine too. You can ignite the fumes from the melted wax to keep the smoke down.

[largom]

As directed by others, turn your heat up a little. Hopefully you have a thermometer and are not going by the dial on your pot. When you flux cover the top of the melt with sawdust and then stir well.

Larry

[mdi]

Wow! Where was my head? I saw the thread title and thought you were fluxing with Oatmeal (ya know, like Quaker Oats). I just might try Oatmeal flux next time I do some casting just to see if it works. Prolly smell good too...

[chutestrate]

Ok, I'm using a thermometer. I'll be making some sawdust this week, and trying the fluxing.

[454PB]

This is very common when melting linotype or other type metals. A lot of people skim it off as dross and waste valuable components.

[GabbyM]

Heat it up to 800 degrees then flux it with white lard. It will smoke and flame a lot.

My guess is your casting thermometer is off by about 50 degrees and you're running 650 degrees when it says 700.

[dkf]

I get a small bit of "oatmeal stuff" on top of the melt sometimes and it can be hard to get it to go back in. I figure it is some alloys that got separated from the heat cool cycles I put it through from several cast sessions. I have found candle wax as a flux mixes it in real quick for me. Paraffin canning wax did not do it but the candle wax sure did.

[trapper9260]

Wow! Where was my head? I saw the thread title and thought you were fluxing with Oatmeal (ya know, like Quaker Oats). I just might try Oatmeal flux next time I do some casting just to see if it works. Prolly smell good too...

When I seen the post, I was thinking of the same thing also.Let us know if you do use and let us know how it work out.Make a different post on it.

[chutestrate]

I will. I have a few different suggestions to try. I'll definitely try the candle wax since I can get my hands on some of the stanky candles my wife insists on buying. I'll have sawdust to try a little later in the week.

I imagine that these methods make a bit of smoke?

[Deadpool]

I will. I have a few different suggestions to try. I'll definitely try the candle wax since I can get my hands on some of the stanky candles my wife insists on buying. I'll have sawdust to try a little later in the week.

I imagine that these methods make a bit of smoke?

Ashes from a wood stove or fireplace works just as well, and without any smoke. Throw on a healthy scoop, stir it, and pour ladles of your oatmeal through the ashes. When "flux" like sawdust burn, it's leaving behind carbon. It's the carbon that is used as flux. Ash is simply the end result.

If you still keep getting oatmeal after turning the pot up to 700F (can you measure the temperature?) then you could have zinc contamination. Alloy separation (losing antimony) may only happen at lower temperatures before the whole pot reaches liquidus.

If you do have zinc contamination, a very small amount can cause oatmeal, and it'll keep coming out. So PUT IT ALL BACK IN if you've been removing it, you're just wasting good alloy. A tiny amount can be a good thing but will ruin your boolit after a long aging period, anyway. It's been posted many times on here, clean up your zinc problems using copper sulfate. A tablespoon as "flux", let it turn white before stirring, then stir pour through it, don't remove any unless the white chunks won't go away anymore. You'll be replacing zinc with copper using this stuff, which is very good to have in your alloy.

Copper sulfate will react with zinc much faster than anything else you have in your melt, so ignore what people say about losing tin, it only slowly reacts with tin if there isn't any zinc left, and you'll have a very hard time getting 2% tin to become 1.9% tin with this method.

[dkf]

I will. I have a few different suggestions to try. I'll definitely try the candle wax since I can get my hands on some of the stanky candles my wife insists on buying. I'll have sawdust to try a little later in the week.

I imagine that these methods make a bit of smoke?

The candle wax smokes quite a bit. A match to make sure the wax on top lights off helps keep smoke down. Make sure to wear gloves while you stir in the wax.

[texassako]

Fluxing removes stuff, reducing converts oxides back into the useable components. A ball of wax, lit after it melts and stirred while flaming, will eliminate the oxygen and reduce the oxides for you. It may take a bit more heat than the usual casting temp.

[btroj]

Ashes from a wood stove or fireplace works just as well, and without any smoke. Throw on a healthy scoop, stir it, and pour ladles of your oatmeal through the ashes. When "flux" like sawdust burn, it's leaving behind carbon. It's the carbon that is used as flux. Ash is simply the end result.

If you still keep getting oatmeal after turning the pot up to 700F (can you measure the temperature?) then you could have zinc contamination. Alloy separation (losing antimony) may only happen at lower temperatures before the whole pot reaches liquidus.

If you do have zinc contamination, a very small amount can cause oatmeal, and it'll keep coming out. So PUT IT ALL BACK IN if you've been removing it, you're just wasting good alloy. A tiny amount can be a good thing but will ruin your boolit after a long aging period, anyway. It's been posted many times on here, clean up your zinc problems using copper sulfate. A tablespoon as "flux", let it turn white before stirring, then stir pour through it, don't remove any unless the white chunks won't go away anymore. You'll be replacing zinc with copper using this stuff, which is very good to have in your alloy.

Copper sulfate will react with zinc much faster than anything else you have in your melt, so ignore what people say about losing tin, it only slowly reacts with tin if there isn't any zinc left, and you'll have a very hard time getting 2% tin to become 1.9% tin with this method.

Ashes from a fireplace will not do anything. You need low order combustion. Ashes won't burn.

[GabbyM]

Ashes from a fireplace will not do anything. You need low order combustion. Ashes won't burn.

Low order combustion. Well the lard at 800 degrees I suggested will rise a flame about a foot above the pot. That's what I meant by smoke and flame a lot. Little bit past low order combustion I'd suspect. I like to toss in some wood chips first. To get a fire started so the grease fumes don't build up and flash off. Candles work well to. Fancy flux is bees wax blended with lard. Sometimes known as black powder bullet lube. If you don't have a decent vented hood it may be time to go outside.

[btroj]

By low order I mean smokey. Lots of carbon monoxide is produced, that is the primary reducing agent.

[leadman]

I use Marvelux on lead alloy like this. Works well. Also Zep Root Killer which is copper sulfate will work. Be sure to leave it on the top of the pot until it changes from blue to white or you may have a visit from an unpleasant fairy.

[44man]

Our metals will alloy in at 600* but zinc will float into oatmeal. If you flux you just alloy in the zinc. Raising heat and fluxing just puts the zinc in easier. If a bunch of stick on weights were used you will have zinc.
I use pure antimony to make a harder mix and it melts in and alloys just fine at 600*, never go higher. Just needs the proper flux.
Get your lead to 600* and skim the oatmeal off, save it to play with later by itself. I can't see losing any good stuff since the zinc is not in alloy with anything. As long as you have tin, the antimony will stay in solution at 600*, it will not float.
Tin helps prevent oxidation at 700 to 750* hotter can reduce that ability and needs more fluxing to keep it in solution.