Well, I believe fluxing does absolutely no harm, so I would normally not feel any need to argue against it. But, I have a feeling the original poster has already had successful casting without using any kind of flux, and is now wondering what he's missing by not using it. So, with that in mind, I hope to present a logical argument as to the ineffectiveness of fluxing, and welcome any feedback as to the validity of my argument.
Let's go over some of the purported benifits of fluxing. It has been stated by a few, that flux will attach to unwanted alloys in the lead (tin, antimony, etc) and bring them to the top so they can be skimmed off, leaving pure lead in the pot. This is probably the weakest argument, as most of us recognize that this is simply impossible, alloys cannot be separated in this manner. If you're one of the few who believe this, ask a metalurgist for the truth. Let's move on.
Some here state that flux will mix with the lead, and and attach to the impurities, and then bring them to the surface, which then allows them to be skimmed off. Now take a minute to really think about this. Ask yourself if it's really possible to mix something as light as wax, sawdust, fat, etc, with something as heavy as lead, a whole potful, and somehow stay submerged long enough to grab onto any crud, and then decide to float to the top. The only way to submerge these light materials under the surface of the lead is to force them down with a ladle, or stick, and only the very small amount of flux particles directly under the ladle will actually penetrate the lead. As soon as the ladle is lifted out of the lead, any flux in the lead will immediately follow to the surface. Try mixing oil and water, and you will get the same result, only the difference in density between lead and organic material is far greater, so the separating effect will be much faster, in fact, instananeous. You just can't mix lead and light organic materials together. Am I wrong here?
It's also been suggested that flux creates a barrier layer on the surface of the lead, preventing the surface of the lead from oxidizing. This makes sense, but if you have a burned layer of carbon floating on your lead, don't you need to skim it off before you pour, so you don't scoop it up with your ladle and pour it into your balls? There goes that protective layer. Does this make sense?
paulvallandigham said:
Because lead is so much heavier than any flux you might try to use, including saw dust, you simply cannot PUSH the flux down into molten lead. What you can do is use a long handled spoon( they get very hot very quickly, so wear gloves!) To stir the molten lead, so that the suspended particles can work to the surface and combine with the carbon.
Exactly Paul, but if you stir the lead, and the particles work to the surface anyway, why do they need to combine with carbon to be skimmed off? Can't you just stir and skim off the impurities without all that burned crud floating on the surface? That's exactly what I do, without fluxing, and it's been working fine for many years. Since you need to skim off the oxidation from time to time anyway, aren't you going to pick up any impurities without using all that smoking material? And what does "combining" mean? The few times I have used flux, I found no actual combining, just that the oxidation and crud in the lead happened to float to the top, occupying the same space at the same time as the flux. All these materials were physically touching, but there was no combining of any sort in my opnion.
I recover an average of 8 out of 10 balls from the dirt where I shoot, and regularly re-melt them to cast new balls. They are about as cruddy as they can get, but after a few stirs of the pot, I have found that the imbedded dirt floats to the top, without any assistance from any kind of flux. Lighter material is going to float to the top of the lead. It's just physics.
Before you readers fall asleep on me, let me give an example of my points that some of you may be familiar with. For those who use cast iron pots, or steel pans for casting, you have probably noticed that rust forms under the lead, and needs to be scraped off after the lead melts. As you scrape the bottom of the pot, you will notice that the rust IMMEDIATELY floats to the top. I'm not talking slowly rising and eventually making it's way to the surface, I'm saying the rust takes less than a half second to pop up. I know some of you guys have witnessed this. Now logically speaking, why would one assume that rust will surface instantly, but other impurities will somehow stay submerged and contaminate the lead? Even if no rust exists, wouldn't any contaminates float to the top at close to the same speed as rust? Now, if one feels the need to flux even after scraping off the rust, isn't he working under the assumption that the rust magically passed around any other crud, leaving it stuck in the middle of the lead for no explanable reason? If you've ever scraped rust off the bottom of the pot, it should be clear why any material lighter than lead cannot stay submerged under the surface, and must float to the top.
Since I was a pipefitter for about 12 years, I also had access to, and have used alot of peeled out lead joints to cast balls, oakum and all. Not once have I ever seen the need to use anything to help get all that stuff out of the lead. It just smokes alot and floats up. I've never noticed the balls having a disproportionate good-to-bad ratio, weight-wise, as compared to using pure x-ray lead. Besides, if fluxing with sawdust, wax, and other gummy substances really worked, wouldn't the smoking greasy oakum act as its own flux, cleaning up the lead without the need for additional flux? Something to think about.
Ok, I'm done. No animosity intended here, and I'm not trying to be right, I just can't see any flaws in my logic. Respectfully, I ask you guys to tell me what you think about my argument. Heck, I may be all wrong and learn something new today. :thumbsup: Thanks for reading, Bill.
