Is this just dirt?

[Landshark9025]

Hi all, I have read many posts about the importance of reducing tin back into the melt, fluxing, etc even one where it seemed that if your lead is clean to start with, anything that forms on the top must be tin that has separated out. As I am new, I am likely going overboard with this, but it seems as if this stuff is just dirt.
104529

This is after casting about 2k boolits.

Original lead- COWW purchased from the board here and it looked really clean. Vendor was Jetsfan and everyone raves about it.
Fluxing- at the end of every session I throw a piece of wax in about 1/2 the size of a grape, let it burn off and then try stir it in. Then, at the beginning of the next session, I pile all the old spures and the new lead on top and melt and mix it together. Once that happens, I throw another piece of wax on and let it burn off and then mix it. When that calms down I put about 1/2 - 1" layer of pine sawdust on top and just let it char up and sit there as I cast. The sawdust char usually lasts until the pot is about ready for more lead, in which case I throw more wax on and either add more lead or pack it up. When it gets to the point of being almost gone, I try to mix it back in, one way or another.

This stuff that you see in the pic does not seem to want to mix back in for nothing. If I have the remains of the last session totally covered with sprues, once it all melts, this pops up to the top like a fishing bobber and is totally dry.

Boolits seem to cast ok, but I am just paranoid about throwing out something I should be mixing in. If so, what more can I do to get it back into the melt?

thanks

[flyingmonkey35]

Yup. Even clean coww will have dirt on it. Don't sweat it.

[Teddy (punchie)]

Looks like the same thing I get in my Range Lead, like sand. I take my back to the range I think that dusty sand has to be bad news.

[captaint]

That dusty sand is bad news. Keep it in sealed containers, like an old coffee can. The sawdust is a good idea, I personally forego the wax, just use the sawdust. Before I pull junk out of the melt, I take a spoon and smash it up against the side of the pot a few times. This tends to reduce what's there to just grey dust. I don't feel bad about pulling that out of the melt. I do add tin now and thenk, not a lot if the mold is filling out boolits well. Now, the sprues, that's another deal.
I always put my sprues back in the pot immediately. I have been told this is terrible and I've been told this is fine. I find it to be fine. Doesn't cause any headaches. My take. Mike

[Landshark9025]

Thanks, all. I forgot to mention, when I stir, I use a paint stick so I can scrape off the sides and the bottom real well...that is until it catches fire. :shock:

Ok, so basically we are saying it is "dusty sand and likely a hazard, dispose of properly".

thanks again.

[Shiloh]

Mine don't catch fire, just char.
When putting a wood stick in a molten pot, go SLOWLY. Wood absorbs moisture. I have awakened the tinsel fairy before.

Shiloh

[Landshark9025]

Ahh, thanks for the warning. My paint sticks are pretty thin. Need to go to Home Depot and get some if the 5gallon ones.

[mpmarty]

skip the wax and use sawdust.

[Wayne Smith]

I have read that wax reduces oxides, charcoal absorbs the junk. Two different things to accomplish.

[blikseme300]

Carbon from burning wax and charcoal both absorb oxygen reducing oxides. Charcoal has the added benefit of also absorbing some impurities.

[bangerjim]

I get that same stuff. No big deal. I use beeswax in my casting pots...forever. Sawdust only in smelting pot 3x.

Sawdust = fluxing action
Beeswax = reducing action

Different actions....both positive and highly desired in different location.

I use a pea-sized piece of beeswax (only!) when the "stuff" forms on the surface, stir immediately from bottom up, and surface turns a beautiful shiny silver and after about 30 seconds of stirring, there is only a little black carbon left on the surface. No crud from brunt sawdust to plug anything up. I know there are those on here that will argue till they are blue in the face that sawdust cannot go to the bottom, but cannot explain where that black crud "on the bottom" comes from and plugs the spout or causes drips. I tired dust and after I quit using dust in the casting pot, I do not have that black crud on the bottom anymore.

If your ingots were processed correctly, there should be no crud to burn off with sawdust in the casting pot! Only beeswax needed to reduce the Sn/Sb back in.

Why beeswax? Smells great, higher flash point and rarely ever catches fire, easy to cut and roll into a little ball, & seems to reduce MUCH better than paraffin (cheap candlewax).

I have aways dumped my sprue lead immediately back in the pot. Never a problem. Some do....some don't. Your call.

bangerjim

[Landshark9025]

Thanks, all. I do the wax and the sawdust as I couldn't decide which and I thought "nothing to lose by doing both". It would be nice to ditch the sawdust as it really puts off a ton of smoke until it all chars over. That said, if I don't use sawdust, within a couple of minutes I get an ugly film forming on top of the melt again. I "lose the shiny" almost immediately. Is that normal? I keep the temp around 700.

For sawdust, I use fresh chainsaw grindings. I just put a big box next to the woodpile and stick a log out and cut slices in it until I have enough to fill a coffee can. It is fresh and full of sap.

[Wayne Smith]

"lose the shiny" is the beginning of oxidation. This begins immediately that the surface is exposed to air, and those of us who ladle cast continually add O2 to the mix.

[Landshark9025]

So the layer of sawdust, which becomes charcoal should help cut down on that right? I think I need to get a better ladle- one that allows me to bring melt up from the bottom better. The one I have, if the pot is half empty, the angle of it causes it all to run out as it breaks the surface. Makes it hard to "scoop and dump".

Thanks all


"lose the shiny" is the beginning of oxidation. This begins immediately that the surface is exposed to air, and those of us who ladle cast continually add O2 to the mix.