Smelting/fluxing question

[Mattog22]

I have recently melted down a couple 5 gal buckets of wheel weights. I have read a good amount about fluxing. My problem is that I don't know exactly when or how often to do it. I use a cast iron pot w/ a turkey fryer. I have been melting the wheel weights and skimming them out with all the ****. Then I put a chunk of candle in, let is melt, catch fire, brown on top, then I stir it up and remove the stuff that forms on top. I may do this 1 or 2 more times as I pour ingots or bullets. I also just skim the top every once in a while when the layer seems a bit thick. I recently read a thread or two where people say they flux while the clips are still in. I never saw this on the youtube videos or heard this until I stumbled upon it. I read that what I may be removing on the clips and scraping off the top may be components of my alloy? Could I accidentally be taking important components such as the tin and antimony out of my alloy and causing them too be softer than desired?

Thanks,

Matt

[montana_charlie]

Matt,
There are two jobs we do when working with molten metal that (both) get called 'fluxing'.
During the 'smelting' process the object is to 'clean' the metal, and to 'blend' the various kinds of included scrap into one homogenous liquid. Since you are working with large quantities, and speed determines if you will get all done before it's time to quit, chunks of wax make a good flux.
When all of the clips (and other junk) seems to have come to the top, throw in some wax and stirr well. That should bring more stuff to the surface...and you can start shoveling it out of the pot.
When you think it's all cleaned, another light fluxing (smaller wax hunk) should release the last of the stubborn stuff.

You can pour your ingots now...and it's alright to let the grey scum (that begins to form) get included in those ingots. That scum is 'oxidation', and that's the next subject.

The other job we do which gets called 'fluxing' is when we "reduce oxides".
When using clean metal to cast bullets, the grey scum which forms is oxidized metal. That means molecules of the tin, or lead, or antimony have picked up oxygen atoms from the air. That causes the metal to change into a structure that is unusable to us...and has the appearance of that dry, grey, scum.
When you introduce a carbon-rich substance, it displaces the oxygen and returns the oxides to their original metallic state. The action is called 'reduction'.
You can use a wax for this 'fluxing', but I (personally) feel wax is a 'contaminate' in metal actually being used for casting. (It doesn't hurt the lead, but it might contaminate the mould.)
Other materials, such as sawdust, charcoal, or just a plain wooden stick, are some of the favorite carbon sources among this membership.

If you allowed some scum to be included in your ingots, back when you made them, 'reduction' of those oxides will change it back into alloy.

That should get you going...

CM

[Mattog22]

Thanks, good explanation. I understand that better than most things I've read. So when making the ingots or bullets could I have removed too much tin and antimony by scraping the grey off the top and not fluxing it back in enough?

[steg]

Mattog 22, yes you very well could have, and Montanna gave you advise better than I could have worded it, I use one of those chinese things to remove the clips and any zinc that ended up in there, flux and stirr well while the wax is in there, even if it's flaming, then I remove the dross but don't throw it out, at the end of the session remelt the dross flux the heck out of it and you will be surprised at what you reclaim, which I suspect will have a higher tin content than the rest...............steg

[Mattog22]

I still have the 5 gallon bucket of clips and dross that I have accumulated since I started. Should I set something up to try and reclaim some from this trash bucket? Is it worth it and is there a preferred way to handle that much?

[EDK]

I still have the 5 gallon bucket of clips and dross that I have accumulated since I started. Should I set something up to try and reclaim some from this trash bucket? Is it worth it and is there a preferred way to handle that much?

I'd melt it down to salvage. Weight the resulting ingots or test the hardness. You may be saving the tin/antimony that you removed by accident.

Fluxing with sawdust does a good job and little metal is removed.

:Fire::cbpour::redneck:

[Mattog22]

I will try a stick or sawdust next time

Thanks

Matt