Chapter 3
To flux or not to flux that is the question!
Well that’s a stupid question of course we flux but what is flux?
Merriam- Webster describes flux as the following
flux
Definition of flux
1
: a flowing of fluid from the body: such as
a
: diarrhea
b
: dysentery
2
: a continuous moving on or passing by (as of a stream)
3
: a continued flow
: flood a flux of words
4a
: influx
b
: change,
fluctuation in a state of flux the flux following the death of the emperor
5
: a substance used to promote fusion (as of metals or minerals) especially
: one (such as rosin) applied to surfaces to be joined by soldering, brazing, or welding to clean and free them from oxide and promote their union
6
: the rate of transfer of fluid, particles, or energy across a given surface
Although I am personally familiar with both 1&2 let us stick with 5&6 for now
For some reason the process of fluxing is a touchy subject for some, The real title of this forum should be “The Art, Science and Religion of Bullet Casting” given some of the “discussions” I have seen in the past on many boards. I will attempt to make the reason for fluxing and the actual physical and chemical process clear to the reader without attempting to flair the nerves and passions of some of our readers.
In our little world (and getting smaller by the day) Fluxing means removing unwanted rubbish from out metal and leaving the desired elements intact.
There are really 2 distinct processes of fluxing and yes they do overlap in a way. There are also a number of agents that are use for fluxing (This is where the war starts)
In reality any material that burns to carbon can be used as a fluxing agent for secondary applications (from ingot to bullet)
I am breaking this down on a personal level as I scrap to get the bulk of my base lead metal so really 2 distinct fluxing process are required to get a good bullet
First flux.
I will use scrap lead and wheel weights (I will assume it has been per-sorted – maybe a chapter on wheel weight discrimination would be good – can I say that?) as the first example as most casters will start this way, it’s the cheapest (ya right!)
Again – please use gloves, eye protection and proper clothing for this process (long sleeves or welders greens are best but not necessary) you will soon figure out what works best for you but I am trying to save you from the burn…..
Be as sure as you can that your materials are dry, if you decide to power wash or pre-clean these types of items you will get water mixed in the small cracks and remaining contamination and this is a problem later on.
Some have suggested putting your materials into the pot then turning it on, this is great for the first load but unless you want to do a lot of little loads this only works once. I have a high temp piece of material I put over the top of the pot, this serves 2 purposes 1) limits the splash or popping of wet stuff and 2) limits the amount of free oxygen getting to the mix (more later on this)
Don’t load your pot by hand, even with gloves when you drop more material into the pot it will splash. I use a pair of tongs to put the scrap into the pot – this gives you additional distance from the melt and reduces the splash potential. It also allows me to lift the covering and put material in and if it does pop or splash the material will protect my body from any stray lead rain.
I set my pot at 700F-720F for this operation, this allows the lead to melt but any Zinc that was missed in the sorting process (yep another chapter) and we all will miss some, will not melt and turn your nice pretty lead into shiny mashed potatoes. Zinc melts at 787F Pure lead melts at 621F and lead alloys even lower, just so you know and don’t try to speed up the process until you have a better handle on what you are throwing in your pot.
Now we are getting somewhere, you should after a short time have a nice pool of lead sitting in the bottom of your pot – covered by a big heap of junk, mostly plastic and steel clips, and it really stinks so do this outside they also say in a well ventilated area – I don’t care how well ventilated the area is, the stink that comes off this process is not only toxic but sticks to everything and if you do this in the house or garage you are going to smell it for a very long time so , up to you – you have been advised…
Once I get a load melted I use salad tongs (the kind with the tines on the end) to remove the plastic, clips and other assorted trash, I then repeat this process till my pot is 2/3-3/4 full of metal, When you flux is optional as I have fluxed between each loading upon removal of the trash and I have waited till the pot was full to flux, both ways work so its up to you.
What to flux with – now here is the great point of contention for most casters. Some use sawdust some use over the counter fluxing agents some use their own secrete mixture which has included everything from motor oil to pine needles, The real truth of the matter is it doesn’t matter, as long as its organic and burns to a carbon ash. This is what I refer to as the second flux but let’s get back to the first flux.
Why does the metal look so clean when you remove all the crap?
Because the oils and the assorted trash are burning and creating carbon, its its own flux in a way, this helps displace the oxides but doesn’t do much with the small particles still moving around in the mix. For this I use a borax base flux, you don’t need much just a half teaspoon full or so to cover the melt. I run the pot temp to at least 720 for this, it just seems to work best around this temp for me. Then you stir, and stir, and stir, this is not a quick process and don’t rush it, when I say stir I mean a deep stir, you want to bring as much foreign matter to the surface as you can, in turn the borax, turns into an ashy glass of sorts, this will capture the majority of dirt and “stuff” still remaining in your pot. Once the ash is all black and floaty (not wet) it can be removed with a spoon and leaves you with a nice little pile of black/gray-ish powder. The surface will be nice and shiny and dirt free. The fluxing should be done as many times as needed but usually 1-2 times is all I have ever really needed.
Pour you clean metal into ingots and mark as WW, you now have your first load of base metal ready to get you on your way
The next post will deal with the second flux if this one doesn’t get me thrown off the board….