Lead fluxing?

[bisleyjohn]

I use a bottom pour pot and always flux and skim off the floating rubbish.
But....as it is a bottom pour is there any point?

I’d say yes because, twice (in about twenty years) I have forgotten to top up the pot and once the crud goes down the little hole - end of casting session!

 

[Carl in France]

I’d say yes because, twice (in about twenty years) I have forgotten to top up the pot and once the crud goes down the little hole - end of casting session!

Yes i can see myself doing that is distracted, i will carry on then as i am. Ta.

 

[Stony Broke]

I've always just kept a candle nearby, and hold it in the lead for a few seconds, then use a large spoon to push the melted wax down through the lead. Afterward, just skim off the top and get to casting. Very quick and easy...I always figured it wouldn't hurt anything to remove some of the stuff I didn't need in the lead.

 

[Heelerau]

Bottom pour, I find fluxing brings what appears to be a yellow sulphur compound up from the bottom of the pot. I have used candles, bees wax, I am about to try some fine sawdust just to see. Been a lot of discussion about on some other sites re sawdust, and quite a technical explanation. I think Zonie has quoted the guts of the issue of how saw dust works. I also use a bit of 50/50 lead tin solder on occasion when the casting gods are giving me grief with minnies and Pritchett. An inch or so in my pot works fine. Regular fluxing with beeswax also makes casting easier, plus having a hot spot to preheat my mould and base plug. I was having a run where I was getting runnels shrinking from the base (minnie and Pritchett) for no apparent reason. You usually get that sort of runnel if you don't leave enough puddle on the sprue plate. Might have been some unknown impurity in my lead. Weird as I have been casting since the early 1970s. Mostly for my muzzle loaders, the odd black powder cartridge rifle.

 

[mooman76]

Thanks for the comments. I figured there must be a chemical process of some sort that caused the impurities to surface with the normal dross. I was processing scrap lead and pouring a muffin tin to be melted later for casting. Don't know why but it seems even softer than the raw scrap. Scratches VERY easy with whats left of my thumbnail.

Lead will age harden some, could be why it seemed softer after you melted scrap lead. You aren't able to make lead softer by melting it, or at least from home.

 

[Griz44Mag]

Could give it a hardness test, before and after.

This I have done many-many times. I keep a variety of 1# ingots - some of them custom mixed - with specific hardness.
Select your lead hardness using the LEE second edition lead vs pressure chart and you will never get leading in your barrels and you will get much better accuracy due to proper obturation of the bullet. IT DOES MATTER.
I use the Cabine Tree tester and have for many years now. It is very accurate, repeatable and very easy t read.
I started with the Lee that uses the micro magnifying glass, but found it to be hard t read and was not repeatable.