Do I remove the mush??

[cricco]

Lately, I have been getting a light mushy substance that forms on the top of my pot when casting. I have been trying to flux and remove it, but it seems to just keep reappearing. I now have a coffee can full of this stuff. Is there something I am doing wrong when fluxing? Should I remove this stuff, or just leave it in my mix? I have no trouble casting, but I don't let my pot get too low either.

[docone31]

That mush can be one of several things.
Zinc. The dreaded zinc, except I use it in my castings. Crank up the heat.
It can be alloys/materials from Babbit, or other metals. Or, it can be just plain old lead that has oxides in it. Heat it up and see.
I flux with PAM. Really gets a nice flow going on top of the melt.
What you have collected in the coffee can, I would not toss it yet. Keep adding to it as you see fit, and later, melt it and see what is what. You can melt it, and put some muriatic acid on top of it. If it sizzles with vigor, then you have your answer. It is zinc. It could also be a bunch of anitimony. That is good stuff to hang on to.
Keep collecting it, and experiment.

[sagacious]

Can't say what you might be doing wrong when fluxing, as your fluxing process/material/etc is not described.

No sure answer can be given as to the nature of the "mush," as the source of the lead is not given, and the steps taken during melt maintenance are not detailed.

Casters may have fill-out problems both when zinc is present, and when it is not, so that's not a relaible descriminator. Going by the most likely odds, it's probably antimony-rich dross and oxides. Do not dispose of your "mush" just yet, as you may be able to reclaim it.

Provide some more info, and a more accurate disgnosis can be made. Good luck.

[lwknight]

Do the drop of muratic acid test to prove or rule out zinc.
I guess that you mght not have much tin to help bind the antimony and its trying to float out.

I agree with " not tossing the dross yet" because it may just be antimony rich oxides that will reduce back in with a generous piece of wax and some vigorous stirring.

[finishman2000]

if your using range lead it may be dirt. i take a spoon and press the "much" against the side and squeeze hard. the amount of mush should get smaller and smaller till you see the dirt or sand.

[oso]

What has changed "lately", what's your metal source, are you smelting in your casting pot, how are you fluxing and now many times (i.e. double flux), what's your working temp? If test for zinc is negative try smelting your dross and see what happens.